Association Between Symptom Burden and Early Lymphatic Abnormalities After Regional Nodal Irradiation for Breast Cancer

PURPOSE

Dermal backflow visualized on near-infrared fluorescence lymphatic imaging (NIRF-LI) signals preclinical lymphedema that precedes the development of volumetrically defined lymphedema. We sought to evaluate whether dermal backflow correlates with patient-reported lymphedema outcomes (PRLO) surveys in breast cancer patients treated with regional nodal irradiation (RNI).

METHODS AND MATERIALS

Patients with breast cancer planned for axillary dissection and RNI prospectively underwent perometry, NIRF-LI, and PRLOs (the Lymphedema Symptom Intensity and Distress Survey [LSIDS] and QuickDASH) at baseline, after surgery, and at 6, 12, and 18 months after radiation. Clinical lymphedema was defined as an arm volume increase ≥5% over baseline. Trends over time were assessed using analysis of variance testing. The association between survey responses and both dermal backflow and lymphedema was assessed using a linear mixed-effects model.

RESULTS

Sixty participants completed at least 2 sets of measurements and surveys and were eligible for analysis. Fifty-four percent of patients had cT3-T4 disease, 53% cN3 disease, and 75% had a body mass index >25. Dermal backflow and clinical lymphedema increased from 10% to 85% and from 0% to 40%, respectively, from baseline to 18 months. In the adjusted model, soft tissue sensation, neurologic sensation, and functional LSIDS subscale scores were associated with presence of dermal backflow (all P < .05). Both dermal backflow and lymphedema were associated with QuickDASH score (P < .05).

CONCLUSIONS

In this high-risk cohort, we found highly prevalent early signs of lymphedema, with increased symptom burden from baseline. Presence of dermal backflow correlated with PRLO measures, highlighting a potential NIRF-LI use to identify patients for early intervention trials after RNI.

Partial Breast Irradiation for Patients With Early-Stage Invasive Breast Cancer or Ductal Carcinoma In Situ: An ASTRO Clinical Practice Guideline

PURPOSE

This guideline provides evidence-based recommendations on appropriate indications and techniques for partial breast irradiation (PBI) for patients with early-stage invasive breast cancer and ductal carcinoma in situ.

METHODS

ASTRO convened a task force to address 4 key questions focused on the appropriate indications and techniques for PBI as an alternative to whole breast irradiation (WBI) to result in similar rates of ipsilateral breast recurrence (IBR) and toxicity outcomes. Also addressed were aspects related to the technical delivery of PBI, including dose-fractionation regimens, target volumes, and treatment parameters for different PBI techniques. The guideline is based on a systematic review provided by the Agency for Healthcare Research and Quality. Recommendations were created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

PBI delivered using 3-dimensional conformal radiation therapy, intensity modulated radiation therapy, multicatheter brachytherapy, and single-entry brachytherapy results in similar IBR as WBI with long-term follow-up. Some patient characteristics and tumor features were underrepresented in the randomized controlled trials, making it difficult to fully define IBR risks for patients with these features. Appropriate dose-fractionation regimens, target volume delineation, and treatment planning parameters for delivery of PBI are outlined. Intraoperative radiation therapy alone is associated with a higher IBR rate compared with WBI. A daily or every-other-day external beam PBI regimen is preferred over twice-daily regimens due to late toxicity concerns.

CONCLUSIONS

Based on published data, the ASTRO task force has proposed recommendations to inform best clinical practices on the use of PBI.

Patient Interest in Exploring Nonsurgical Treatment Approaches for Early-Stage Breast Cancer: A Qualitative Study

PURPOSE

Advances in radiation therapy have enabled the ability to deliver ablative treatments, but there has been limited application of these treatments to early-stage breast cancers with a goal of omitting surgery. The purpose of this study was to explore patient interest in pursuing nonsurgical treatment approaches for their early-stage breast cancer.

METHODS AND MATERIALS

We conducted a qualitative study involving interviews with 21 patients with early-stage breast cancer who were eligible for participation in a phase 2 clinical trial offering omission of definitive surgery. Interviews were transcribed and an inductive, thematic analysis was performed by 3 independent reviewers to generate themes and subthemes.

RESULTS

Data analysis revealed the following factors that affected patient willingness and desire to explore nonsurgical treatment options: (1) perceptions and feelings about their cancer; (2) current quality of life and the level of support available in their daily life; (3) external conversations focusing on family members' and friends' experiences with cancer and/or cancer treatments; (4) personal health care experiences, including their current breast cancer diagnosis; (5) perceptions and feelings about their physicians; (6) conversations with their physicians about their treatment options; and (7) self-identified desire to direct care decisions. Specifically, patients verbalized fearing surgery and surgical recovery; wanting to preserve their breast(s); the prior negative surgical experiences of friends, family, and themselves; a desire to receive treatment per the latest research; wanting to match the level of treatment with the severity of their cancer; and other comorbidities as reasons for wanting to explore omitting surgery.

CONCLUSIONS

Our findings demonstrate an unmet need directed by patient interest to explore nonsurgical options for early-stage, biologically favorable breast cancer. These results may shape conversations around shared decision-making and clinical trial design, and result in more personalized treatment options for women with early-stage breast cancer.

Neoadjuvant radioimmunotherapy synergy in triple-negative breast cancer: Is microenvironment-guided patient selection on the horizon?

Neoadjuvant chemotherapy plus immunotherapy for triple-negative breast cancer (TNBC) is associated with improved but incomplete response. In this issue of Cancer Cell, Shiao et al. characterize longitudinal biopsies from a window of opportunity study with single-cell RNA sequencing (scRNA-seq) and spatial proteomic profiling and elucidate synergy between radiotherapy (RT) and pembrolizumab.

Addition of Metastasis-Directed Therapy to Standard of Care Systemic Therapy for Oligometastatic Breast Cancer (EXTEND): A Multicenter, Randomized Phase II Trial

PURPOSE/OBJECTIVE(S)

Prior retrospective and prospective evidence have suggested a potential survival benefit of adding metastasis-directed therapy (MDT) to standard of care systemic therapy for oligometastatic breast cancer. This has led to the increased utilization of MDT in this setting despite the lack of randomized evidence to support this approach. Furthermore, the recent presentation of NRG-BR002 has questioned the value of MDT. Thus, we evaluated whether the addition of MDT to systemic therapy improves PFS in oligometastatic breast cancer.

MATERIALS/METHODS

EXTEND (NCT03599765) is a phase II randomized basket trial for multiple solid tumors testing whether the addition of MDT improves PFS. The primary endpoint was pre-specified to be independently assessed and reported for the breast basket when a minimum of 6 months of follow-up had been reached. Patients with ≤5 metastases were randomized to standard of care systemic therapy with or without MDT. The choice of systemic therapy was at the discretion of the treating medical oncologist. Number of metastatic lesions and prior lines of systemic therapy for metastatic disease were used as stratification variables pre-randomization. The primary endpoint was progression-free survival (PFS) defined as time to randomization to date of clinical or radiographic progression or death. The study was designed to have 80% power to detect an improvement in median PFS from 18 to 36 months, with a type I error of 0.1.

RESULTS

Between September 2018 to July 2022, 43 patients were randomized. 22 patients were assigned to the MDT arm, and 21 patients to the no MDT arm. Three patients were not evaluable. The MDT arm patients were older vs the no-MDT arm patients (median 61.5 years vs 48 years, p = 0.01). Otherwise, the arms were well-balanced. Overall, 8 patients had triple negative disease (18.6%), and 12 patients (30%) had de novo metastatic disease. Of those patients with de novo presentation randomized to MDT, all except one had the primary tumor treated with surgery and radiation. At a median follow-up of 19.4 months, 20 events were observed. Among the 40 evaluable patients, there were 5 deaths (3 in the MDT arm and 2 in the no MDT arm). There was no difference in PFS between the MDT and no MDT arms (median 15.6 v 24.9 months, p = 0.66). Similarly, there was no difference in the secondary endpoint of time to new metastatic lesion appearance between the MDT and no MDT arms (median 15.6 months vs not reached, p = 0.09). Two grade 3 toxicities were observed in the MDT arm, and 1 in the no MDT arm. Further analysis of correlative translational biomarkers, including immune markers and ctDNA, are ongoing.

CONCLUSION

The addition of MDT to standard of care systemic therapy did not improve PFS or time to new metastatic lesion in patients with oligometastatic breast cancer. This data coupled with the recently presented NRG-BR002 results, suggests there is no benefit to MDT in an otherwise unselected oligometastatic breast cancer population.

Automated contouring and statistical process control for plan quality in a breast clinical trial

Background and purpose

Automatic review of breast plan quality for clinical trials is time-consuming and has some unique challenges due to the lack of target contours for some planning techniques. We propose using an auto-contouring model and statistical process control to independently assess planning consistency in retrospective data from a breast radiotherapy clinical trial.

Materials and methods

A deep learning auto-contouring model was created and tested quantitatively and qualitatively on 104 post-lumpectomy patients' computed tomography images (nnUNet; train/test: 80/20). The auto-contouring model was then applied to 127 patients enrolled in a clinical trial. Statistical process control was used to assess the consistency of the mean dose to auto-contours between plans and treatment modalities by setting control limits within three standard deviations of the data's mean. Two physicians reviewed plans outside the limits for possible planning inconsistencies.

Results

Mean Dice similarity coefficients comparing manual and auto-contours was above 0.7 for breast clinical target volume, supraclavicular and internal mammary nodes. Two radiation oncologists scored 95% of contours as clinically acceptable. The mean dose in the clinical trial plans was more variable for lymph node auto-contours than for breast, with a narrower distribution for volumetric modulated arc therapy than for 3D conformal treatment, requiring distinct control limits. Five plans (5%) were flagged and reviewed by physicians: one required editing, two had clinically acceptable variations in planning, and two had poor auto-contouring.

Conclusions

An automated contouring model in a statistical process control framework was appropriate for assessing planning consistency in a breast radiotherapy clinical trial.

Patient-Reported Outcomes of Omission of Breast Surgery Following Neoadjuvant Systemic Therapy: A Nonrandomized Clinical Trial

Importance

Patients should have an active role in decisions about pursuing or forgoing specific therapies in treatment de-escalation trials.

Objective

To evaluate longitudinal patient-reported outcomes (PROs) encompassing decisional comfort and health-related quality of life (HRQOL) among patients who elected to enroll in a clinical trial evaluating radiotherapy alone, without breast surgery, for invasive breast cancers with exceptional response to neoadjuvant systemic therapy (NST).

Design, Setting, and Participants

Prospective, single-group, phase 2 clinical trial at 7 US medical centers. Women aged 40 years or older with invasive cT1-2 N0-1 M0 triple-negative or human epidermal growth factor receptor 2 (ERBB2)-positive breast cancer with no pathologic evidence of residual disease following standard NST enrolled from March 6, 2017, to November 9, 2021. Validated PRO measures were administered at baseline and 6, 12, and 36 months post-radiotherapy. Data were analyzed from January to February 2023.

Interventions

PRO measures included the Decision Regret Scale (DRS), Functional Assessment of Cancer Therapy-Lymphedema (FACT-B+4), and Breast Cancer Treatment Outcomes Scale (BCTOS).

Main Outcomes and Measures

Changes in PRO measure scores and subscores over time.

Results

Among 31 patients, the median (IQR) age was 61 (56-66) years, 26 (84%) were White, and 26 (84%) were non-Hispanic. A total of 15 (48%) had triple-negative disease and 16 (52%) had ERBB2-positive disease. Decisional comfort was high at baseline (median [IQR] DRS score 10 [0-25] on a 0-100 scale, with higher scores indicating higher decisional regret) and significantly increased over time (median [IQR] DRS score at 36 months, 0 [0-20]; P < .001). HRQOL was relatively high at baseline (median [IQR] FACT-B composite score 121 [111-134] on a 0-148 scale, with higher scores indicating higher HRQOL) and significantly increased over time (median [IQR] FACT-B score at 36 months, 128 [116-137]; P = .04). Perceived differences between the affected breast and contralateral breast were minimal at baseline (median [IQR] BCTOS score 1.05 [1.00-1.23] on a 1-4 scale, with higher scores indicating greater differences) and increased significantly over time (median [IQR] BCTOS score at 36 months, 1.36 [1.18-1.64]; P < .001). At 36 months postradiotherapy, the cosmetic subscore was 0.45 points higher than baseline (95% CI, 0.16-0.74; P = .001), whereas function, pain, and edema subscores were not significantly different than baseline.

Conclusions and Relevance

In this nonrandomized phase 2 clinical trial, analysis of PROs demonstrated an overall positive experience for trial participants, with longitudinal improvements in decisional comfort and overall HRQOL over time and minimal lasting adverse effects of therapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02945579.

Prospective, early longitudinal assessment of lymphedema-related quality of life among patients with locally advanced breast cancer: The foundation for building a patient-centered screening program

BACKGROUND

We examined how breast cancer-related lymphedema (BCRL) affects health-related quality of life (HRQOL), productivity, and compliance with therapeutic interventions to guide structuring BCRL screening programs.

METHODS

We prospectively followed consecutive breast cancer patients who underwent axillary lymph node dissection (ALND) with arm volume screening and measures assessing patient-reported health-related quality of life (HRQOL) and perceptions of BCRL care. Comparisons by BCRL status were made with Mann-Whitney U, Chi-square, Fisher's exact, or t tests. Trends over time from ALND were assessed with linear mixed-effects models.

RESULTS

With a median follow-up of 8 months in 247 patients, 46% self-reported ever having BCRL, a proportion that increased over time. About 73% reported fear of BCRL, which was stable over time. Further in time from ALND, patients were more likely to report that BCRL screening reduced fear. Patient-reported BCRL was associated with higher soft tissue sensation intensity, biobehavioral, and resource concerns, absenteeism, and work/activity impairment. Objectively measured BCRL had fewer associations with outcomes. Most patients reported performing prevention exercises, but compliance decreased over time; patient-reported BCRL was not associated with exercise frequency. Fear of BCRL was positively associated with performing prevention exercises and using compressive garments.

CONCLUSIONS

Both incidence and fear of BCRL were high after ALND for breast cancer. Fear was associated with improved therapeutic compliance, but compliance decreased over time. Patient-reported BCRL was more strongly associated with worse HRQOL and productivity than was objective BCRL. Screening programs must support patients' psychological needs and aim to sustain long-term compliance with recommended interventions.

Socioeconomic Barriers to Randomized Clinical Trial Retention in Patients Treated With Adjuvant Radiation for Early-Stage Breast Cancer

PURPOSE

Socioeconomic barriers contribute to breast cancer clinical trial enrollment disparities. We sought to identify whether socioeconomic disadvantage also is associated with decreased trial retention.

METHODS AND MATERIALS

We performed a secondary analysis of 253 (of 287) patients enrolled in a randomized phase 3 trial of conventionally fractionated versus hypofractionated whole-breast irradiation. The outcome of trial retention versus dropout was defined primarily based on whether the patient completed breast cosmesis outcomes assessment at 3-year follow-up, and secondarily, at 5-year follow-up. Associations of retention with severity of socioeconomic disadvantage, quantified by patients' home neighborhood area deprivation index (ADI) rank (1 [least] to 100 [most deprivation]), were tested using the Kruskal-Wallis test and multivariate logistic regression. Associations of retention with patients' use of social resource assistance were analyzed using the χ² test.

RESULTS

In total, 21.7% (n = 55) of patients dropped out by 3 years and 36.7% (n = 92) by 5 years. Median ADI was 36.5 (interquartile range, 22-57) for retained and 46.0 (interquartile range, 29-60) for dropout patients. Dropout was associated with more severe socioeconomic deprivation (ADI ≥45 vs <45) at 3 years (odds ratio, 3.63; 95% confidence interval, 1.62-8.15; P = .002) and 5 years (odds ratio, 2.55; 95% confidence interval, 1.37-4.76; P = .003). While on study, patients who ultimately dropped out were more likely to require resource assistance for practical (transportation, housing, financial) than psychological needs (distress, grief) or advance care planning (P = .03).

CONCLUSIONS

In this study, ADI was associated with disparities in clinical trial retention of patients with breast cancer receiving adjuvant radiation treatment. Results suggest that developing multidimensional interventions that extend beyond routine social determinants needs screening are needed, not only to enhance initial clinical trial access and enrollment but also to enable robust long-term retention of socioeconomically disadvantaged patients and improve the validity and generalizability of reported long-term trial clinical and patient-reported outcomes.

Plasma Cytokines/Chemokines as Predictive Biomarkers for Lymphedema in Breast Cancer Patients

Breast cancer-related lymphedema (BCRL) occurs in ~ 40% of patients after axillary lymph node dissection (ALND), radiation therapy (RT), or chemotherapy. First-line palliative treatment utilizes compression garments and specialized massage. Reparative microsurgeries have emerged as a second-line treatment, yet both compression and surgical therapy are most effective at early stages of LE development. Identifying patients at the highest risk for BCRL would allow earlier, more effective treatment. Perometric arm volume measurements, near-infrared fluorescent lymphatic imaging (NIRF-LI) data, and blood were collected between 2016 and 2021 for 40 study subjects undergoing treatment for breast cancer. Plasma samples were evaluated using MILLIPLEX human cytokine/chemokine panels at pre-ALND and at 12 months post-RT. A Mann-Whitney t-test showed that G-CSF, GM-CSF, IFN-2α, IL-10, IL-12p40, IL-15, IL-17A, IL-1β, IL-2, IL-3, IL-6, and MIP-1β were significantly higher at pre-ALND in those presenting with BCRL at 12 months post-RT. MIP-1β and IL-6 were significantly higher at pre-ALND in those who developed dermal backflow, but no BCRL, at 12 months post-RT. Plasma IL-15, IL-3, and MIP-1β were elevated at 12 months after RT in those with clinical BCRL. These findings establish BCRL as a perpetual inflammatory disorder, and suggest the use of plasma cytokine/chemokine levels to predict those at highest risk.

Effectiveness Without Efficacy: Cautionary Tale from a Landmark Breast Cancer Randomized Controlled Trial

Background: "Old" randomized controlled trials established breast conserving therapy (BCT) and total mastectomy (TM) equivalence for treating early breast cancer, whereas recent literature report improved survival with BCT. To reconcile this, we performed a simulation study and re-analyzed B-06 trial data. Methods: We estimated the distributions for overall survival (OS), cumulative incidence functions for breast-cancer-specific death (BCSD) and other causes-specific death (OCSD) by BCT and TM. The restricted mean survival time (RMST) difference and hazard ratio between the two arms were estimated. Given the estimated distributions, we simulated cause-specific death times from each arm, evaluating the power to test treatment difference in OS, BCSD, and OCSD with different sample sizes, follow-up times, and a modified setting by simulating BCT-arm OCSD times from the distribution of patients not receiving radiation. Results: With 200 months follow-up, the average BCT-over-TM gain measured by RMST was 3.7 months for OS and 4.5 months for BCSD. Increasing the trial size to 5,000 per arm, there is a 79.2% chance to detect the OS benefit with RMST and 92.4% for BCSD. A nonproportional increase of OCSD in BCT compared to TM was observed after 144 months, and particularly after 200 months post treatments. When OCSD times of BCT were simulated using patients not receiving radiation, the estimated OS gain increased to 4.4 months, and the power increased to 92.2%. Conclusions: The late excess other-cause-death, likely due to radiation, in the BCT arm and sample size constraints limited the power to report BCT superiority. Given radiation delivered in the era of B-06 trial, BCT and TM remain largely equivalent.

Targeted Inhibition of DNA-PKcs, ATM, ATR, PARP, and Rad51 Modulate Response to X Rays and Protons

Small molecule inhibitors are currently in preclinical and clinical development for the treatment of selected cancers, particularly those with existing genetic alterations in DNA repair and DNA damage response (DDR) pathways. Keen interest has also been expressed in combining such agents with other targeted antitumor strategies such as radiotherapy. Radiotherapy exerts its cytotoxic effects primarily through DNA damage-induced cell death; therefore, inhibiting DNA repair and the DDR should lead to additive and/or synergistic radiosensitizing effects. In this study we screened the response to X-ray or proton radiation in cell lines treated with DDR inhibitors (DDRis) targeting ATM, ATR, DNA-PKcs, Rad51, and PARP, with survival metrics established using clonogenic assays. We observed that DDRis generate significant radiosensitization in cancer and primary cells derived from normal tissue. Existing genetic defects in cancer cells appear to be an important consideration when determining the optimal inhibitor to use for synergistic combination with radiation. We also show that while greater radiosensitization can be achieved with protons (9.9 keV/µm) combined with DDRis, the relative biological effectiveness is unchanged or in some cases reduced. Our results indicate that while targeting the DDR can significantly radiosensitize cancer cells to such combinations, normal cells may also be equally or more severely affected, depending on the DDRi used. These data highlight the importance of identifying genetic defects as predictive biomarkers of response for combination treatment.

Effect of boron compounds on the biological effectiveness of proton therapy

PURPOSE

We assessed whether adding sodium borocaptate (BSH) or 4-borono-l-phenylalanine (BPA) to cells irradiated with proton beams influenced the biological effectiveness of those beams against prostate cancer cells to investigate if the alpha particles generated through proton-boron nuclear reactions would be sufficient to enhance the biological effectiveness of the proton beams.

METHODS

We measured clonogenic survival in DU145 cells treated with 80.4-ppm BSH or 86.9-ppm BPA, or their respective vehicles, after irradiation with 6-MV X-rays, 1.2-keV/μm (low linear energy transfer [LET]) protons, or 9.9-keV/μm (high-LET) protons. We also measured γH2AX and 53BP1 foci in treated cells at 1 and 24 h after irradiation with the same conditions.

RESULTS

We found that BSH radiosensitized DU145 cells across all radiation types. However, no difference was found in relative radiosensitization, characterized by the sensitization enhancement ratio or the relative biological effectiveness, for vehicle- versus BSH-treated cells. No differences were found in numbers of γH2AX or 53BP1 foci or γH2AX/53BP1 colocalized foci for vehicle- versus BSH-treated cells across radiation types. BPA did not radiosensitize DU145 cells nor induced any significant differences when comparing vehicle- versus BPA-treated cells for clonogenic cell survival or γH2AX and 53BP1 foci or γH2AX/53BP1 colocalized foci.

CONCLUSIONS

Treatment with 11 B, at concentrations of 80.4 ppm from BSH or 86.9 ppm from BPA, had no effect on the biological effectiveness of proton beams in DU145 prostate cancer cells. Our results agree with published theoretical calculations indicating that the contribution of alpha particles from such reactions to the total absorbed dose and biological effectiveness is negligible. We also found that BSH radiosensitized DU145 cells to X-rays, low-LET protons, and high-LET protons but that the radiosensitization was not related to DNA damage.

An empirical model of proton RBE based on the linear correlation between x-ray and proton radiosensitivity

BACKGROUND

Proton relative biological effectiveness (RBE) is known to depend on physical factors of the proton beam, such as its linear energy transfer (LET), as well as on cell-line specific biological factors, such as their ability to repair DNA damage. However, in a clinical setting, proton RBE is still considered to have a fixed value of 1.1 despite the existence of several empirical models that can predict proton RBE based on how a cell's survival curve (linear-quadratic model [LQM]) parameters α and β vary with the LET of the proton beam. Part of the hesitation to incorporate variable RBE models in the clinic is due to the great noise in the biological datasets on which these models are trained, often making it unclear which model, if any, provides sufficiently accurate RBE predictions to warrant a departure from RBE = 1.1.

PURPOSE

Here, we introduce a novel model of proton RBE based on how a cell's intrinsic radiosensitivity varies with LET, rather than its LQM parameters.

METHODS AND MATERIALS

We performed clonogenic cell survival assays for eight cell lines exposed to 6 MV x-rays and 1.2, 2.6, or 9.9 keV/µm protons, and combined our measurements with published survival data (n = 397 total cell line/LET combinations). We characterized how radiosensitivity metrics of the form DSF% , (the dose required to achieve survival fraction [SF], e.g., D10% ) varied with proton LET, and calculated the Bayesian information criteria associated with different LET-dependent functions to determine which functions best described the underlying trends. This allowed us to construct a six-parameter model that predicts cells' proton survival curves based on the LET dependence of their radiosensitivity, rather than the LET dependence of the LQM parameters themselves. We compared the accuracy of our model to previously established empirical proton RBE models, and implemented our model within a clinical treatment plan evaluation workflow to demonstrate its feasibility in a clinical setting.

RESULTS

Our analyses of the trends in the data show that DSF% is linearly correlated between x-rays and protons, regardless of the choice of the survival level (e.g., D10% , D37% , or D50% are similarly correlated), and that the slope and intercept of these correlations vary with proton LET. The model we constructed based on these trends predicts proton RBE within 15%-30% at the 68.3% confidence level and offers a more accurate general description of the experimental data than previously published empirical models. In the context of a clinical treatment plan, our model generally predicted higher RBE-weighted doses than the other empirical models, with RBE-weighted doses in the distal portion of the field being up to 50.7% higher than the planned RBE-weighted doses (RBE = 1.1) to the tumor.

CONCLUSIONS

We established a new empirical proton RBE model that is more accurate than previous empirical models, and that predicts much higher RBE values in the distal edge of clinical proton beams.

Prediction of breast cancer-related lymphedema by dermal backflow detected with near-infrared fluorescence lymphatic imaging

PURPOSE

Mild breast cancer-related lymphedema (BCRL) is clinically diagnosed as a 5%-10% increase in arm volume, typically measured no earlier than 3-6 months after locoregional treatment. Early BCRL treatment is associated with better outcomes, yet amid increasing evidence that lymphedema exists in a latent form, treatment is typically delayed until arm swelling is obvious. In this study, we investigated whether near-infrared fluorescence lymphatic imaging (NIRF-LI) surveillance could characterize early onset of peripheral lymphatic dysfunction as a predictor of BCRL.

METHODS

In a prospective, longitudinal cohort/observational study (NCT02949726), subjects with locally advanced breast cancer who received axillary lymph node dissection and regional nodal radiotherapy (RT) were followed serially, between 2016 and 2021, before surgery, 4-8 weeks after surgery, and 6, 12, and 18 months after RT. Arm volume was measured by perometry, and lymphatic (dys) function was assessed by NIRF-LI.

RESULTS

By 18 months after RT, 30 of 42 study subjects (71%) developed mild-moderate BCRL (i.e., ≥ 5% arm swelling relative to baseline), all manifested by "dermal backflow" of lymph into lymphatic capillaries or interstitial spaces. Dermal backflow had an 83% positive predictive value and 86% negative predictive value for BCRL, with a sensitivity of 97%, specificity of 50%, accuracy of 83%, positive likelihood ratio of 1.93, negative likelihood ratio of 0.07, and odds ratio of 29.00. Dermal backflow appeared on average 8.3 months, but up to 23 months, before the onset of mild BCRL.

CONCLUSION

BCRL can be predicted by dermal backflow, which often appears months before arm swelling, enabling early treatment before the onset of edema and irreversible tissue changes.

Lymphedema in Inflammatory Breast Cancer Patients Following Trimodal Treatment

BACKGROUND

Breast cancer-related lymphedema (BCRL) is a debilitating sequela of breast cancer treatment and is becoming a greater concern in light of improved long-term survival. Inflammatory breast cancer (IBC) is a rare and aggressive malignancy for which systemic therapy, surgery, and radiotherapy remain the standard of care, thereby making IBC patients highly susceptible to developing BCRL. This study evaluated BCRL in IBC following trimodal therapy.

METHODS

IBC patients treated from 2016 to 2019 were identified from an institutional database. Patients were excluded if they presented with recurrent disease, underwent bilateral axillary surgery, did not complete trimodal therapy, or were lost to follow-up. Demographic, clinicopathologic factors, oncologic outcomes, and perometer measurements were recorded. BCRL was defined by clinician diagnosis and/or objective perometer measurements when available. Time to development of BCRL and treatment received were captured.

RESULTS

Eighty-three patients were included. Median follow-up was 33 months. The incidence of BCRL was 50.6% (n = 42). Mean time to BCRL from surgery was 13 (range 2-24) months. Demographic and clinicopathologic features were similar between patients with and without BCRL with exception of higher proportion receiving delayed reconstruction in the BCRL group (38.1% vs. 14.6%, p = 0.03). Forty patients (95.2%) underwent BCRL treatment, which included physical therapy (n = 39), compression (n = 38), therapeutic lymphovenous bypass (n = 13), and/or vascularized lymph node transfer (n = 12).

CONCLUSIONS

IBC patients are at high-risk for BCRL after treatment, impacting 51% of patients in this cohort. Strategies to reduce or prevent BCRL and improve real-time diagnosis should be implemented to better direct early management in this patient population.

Long-term Quality of Life in Patients With Breast Cancer After Breast Conservation vs Mastectomy and Reconstruction

Importance

Treatment options for early breast cancer include breast-conserving surgery with radiation therapy (RT) or mastectomy and breast reconstruction without RT. Despite marked differences in these treatment strategies, little is known with regard to their association with long-term quality of life (QOL).

Objective

To evaluate the association of treatment with breast-conserving surgery with RT vs mastectomy and reconstruction without RT with long-term QOL.

Design, Setting, and Participants

This comparative effectiveness research study used data from the Texas Cancer Registry for women diagnosed with stage 0-II breast cancer and treated with breast-conserving surgery or mastectomy and reconstruction between 2006 and 2008. The study sample was mailed a survey between March 2017 and April 2018. Data were analyzed from August 1, 2018 to October 15, 2021.

Exposures

Breast-conserving surgery with RT or mastectomy and reconstruction without RT.

Main Outcomes and Measures

The primary outcome was satisfaction with breasts, measured with the BREAST-Q patient-reported outcome measure. Secondary outcomes included BREAST-Q physical well-being, psychosocial well-being, and sexual well-being; health utility, measured using the EuroQol Health-Related Quality of Life 5-Dimension, 3-Level questionnaire; and local therapy decisional regret. Multivariable linear regression models with weights for treatment, age, and race and ethnicity tested associations of the exposure with outcomes.

Results

Of 647 patients who responded to the survey (40.0%; 356 had undergone breast-conserving surgery, and 291 had undergone mastectomy and reconstruction), 551 (85.2%) confirmed treatment with breast-conserving surgery with RT (n = 315) or mastectomy and reconstruction without RT (n = 236). Among the 647 respondents, the median age was 53 years (range, 23-85 years) and the median time from diagnosis to survey was 10.3 years (range, 8.4-12.5 years). Multivariable analysis showed no significant difference between breast-conserving surgery with RT (referent) and mastectomy and reconstruction without RT in satisfaction with breasts (effect size, 2.71; 95% CI, -2.45 to 7.88; P = .30) or physical well-being (effect size, -1.80; 95% CI, -5.65 to 2.05; P = .36). In contrast, psychosocial well-being (effect size, -8.61; 95% CI, -13.26 to -3.95; P < .001) and sexual well-being (effect size, -10.68; 95% CI, -16.60 to -4.76; P < .001) were significantly worse with mastectomy and reconstruction without RT. Health utility (effect size, -0.003; 95% CI, -0.03 to 0.03; P = .83) and decisional regret (effect size, 1.32; 95% CI, -3.77 to 6.40; P = .61) did not differ by treatment group.

Conclusions and Relevance

The findings support equivalence of breast-conserving surgery with RT and mastectomy and reconstruction without RT with regard to breast satisfaction and physical well-being. However, breast-conserving surgery with RT was associated with clinically meaningful improvements in psychosocial and sexual well-being. These findings may help inform preference-sensitive decision-making for women with early-stage breast cancer.

Locoregional Management and Prognostic Factors in Breast Cancer Patients with Ipsilateral Internal Mammary and Axillary Lymph Node Involvement

PURPOSE

Breast cancer patients with ipislateral axillary and internal mammary (IM) lymph node involvement (cN3b) often forego IM node resection. Therefore, radiation is important for curative therapy. However, prognosis is not well-described in the era of modern systemic therapy and limited data exist to guide optimal locoregional treatment recommendations.

METHODS

We retrospectively reviewed 117 patients with non-metastatic cN3b breast cancer treated at our institution between 2014-2019. Staging included ultrasound evaluation of all regional nodal basins. All patients received neoadjuvant chemotherapy (NAC), resection of the breast primary and axillary nodal dissection, followed by adjuvant radiation to the breast/chest wall and regional nodes. Institutional guidelines recommend a 10 Gy boost to radiographically resolved nodes, and 16 Gy boost to unresolved nodes. Overall survival (OS), recurrence (RFS), locoregional (LRRFS), internal mammary (IMRFS), and distant metastasis free survival (DMFS) were evaluated with Kaplan Meier analysis. A multivariable model for RFS was constructed.

RESULTS

Median follow-up for 117 patients was 3.82 years. Median age at diagnosis was 46 years and 56 (48%) patients were receptor group ER+/HER2-. Mastectomy was performed in 96 (82%) of patients, 38 (32%) had biopsy confirmed IMC involvement, and 8 (7%) had IM node dissection. The median initial radiation dose was 50 Gy (range, 50-55) and IMC boost 10 Gy (range, 0-16). The 5-year OS, IMRFS, LRRFS, DMFS, and RFS were 74%, 98%, 89%, 68% and 67% respectively. On multivariable analysis, a clinical complete response (CR) of the IM nodes or pathologic ypN0 status had improved 5-year RFS with HR 0.24 (p=0.006) and HR 0.27 (p=0.05), respectively. Extranodal extension or lymphovascular invasion were associated with worse 5-year RFS with HR 4.13 (p=0.001) and HR 2.25 (p=0.04), respectively.

CONCLUSION

Multimodality therapy provides excellent locoregional control of 89% at 5 years for cN3b breast cancer patients. Adjuvant radiation yields a 5-year IMRFS of 98%. Clinical and pathologic response of IM nodes are independently prognostic for RFS.

Adoption of Ultrahypofractionated Radiation Therapy in Patients With Breast Cancer

Introduction

The first high-quality clinical trial to support ultrahypofractionated whole-breast irradiation (ultra-HF-WBI) for invasive early-stage breast cancer (ESBC) was published in April 2020, coinciding with the beginning of the COVID-19 pandemic. We analyzed adoption of ultra-HF-WBI for ductal carcinoma in situ (DCIS) and ESBC at our institution after primary trial publication.

Methods and Materials

We evaluated radiation fractionation prescriptions for all patients with DCIS or ESBC treated with WBI from March 2020 to May 2021 at our main campus and regional campuses. Demographic and clinical characteristics were extracted from the electronic medical record. Treating physician characteristics were collected from licensure data. Hierarchical logistic regression models identified factors correlated with adoption of ultra-HF-WBI (26 Gy in 5 daily factions [UK-FAST-FORWARD] or 28.5 Gy in 5 weekly fractions [UK-FAST]).

Results

Of 665 included patients, the median age was 61.5 years, and 478 patients (71.9%) had invasive, hormone-receptor-positive breast cancer. Twenty-one physicians treated the included patients. In total, 249 patients (37.4%) received ultra-HF-WBI, increasing from 4.3% (2 of 46) in March-April 2020 to a high of 45.5% (45 of 99) in July-August 2020 (P < .001). Patient factors associated with increased use of ultra-HF-WBI included older age (≥50 years old), low-grade WBI without inclusion of the low axilla, no radiation boost, and farther travel distance (P < .03). Physician variation accounted for 21.7% of variance in the outcome, with rate of use of ultra-HF-WBI by the treating physicians ranging from 0% to 75.6%. No measured physician characteristics were associated with use of ultra-HF-WBI.

Conclusions

Adoption of ultra-HF-WBI at our institution increased substantially after the publication of randomized evidence supporting its use. Ultra-HF-WBI was preferentially used in patients with lower risk disease, suggesting careful selection for this new approach while long-term data are maturing. Substantial physician-level variation may reflect a lack of consensus on the evidentiary standards required to change practice.

Abstract P2-06-01: Parp inhibition sensitizes brca deficient cancer cell lines and tumors to clinical x-ray and proton irradiation

Purpose Triple negative breast cancers (TNBC) are more often found among BRCA gene mutation carriers; even among non-mutation carriers, TNBCs are thought to carry a phenotype of BRCAness. Inhibitors of Poly(adenosine diphosphate-ribose) polymerase (PARPi) have improved survival outcomes for both advanced and early stage breast cancer associated with a BRCA mutation, as well as BRCA mutated ovarian and prostate cancers. Radiotherapy (RT) is a widely used treatment to locally control cancers, but it is unclear how different types of RT, including clinical x-rays and protons, interact with PARPi and how these affect antitumor immunity. Protons induce more clustered DNA lesions, including clustered double and single strand breaks (DSBs and SSBs) and clustered base damages, than x-rays due to their higher ionization density. If not properly repaired, DSBs can generate micronuclei (MN), which activate the cyclic GMP-AMP synthase (cGAS) and stimulator of interferon (IFN) genes (STING) (cGAS-STING) pathway, leading to antitumor immunity. Residual DNA damage also induces cellular senescence, which is a known tumor suppressor mechanism. In this study we investigated the effects of combining a PARPi with x-rays or protons on clonogenic cell survival, residual DNA damage, senescence, cGAS co-localization with MN and delay in tumor growth in the context of BRCA1 mutation. Methods In vitro, BRCA1 deficient (HCC1937 and MDA-MB-436) and proficient (HCC1937-BRCA and MDA-MB-436-BRCA) breast cancer cell lines were treated with a PARPi (Olaparib, 0.1 - 5.0 μM) and irradiated with 6 MV x-rays or protons (9.9 keV/um) with doses from 0.5 to 5 Gy. HCC1937-BRCA was gifted from Dr. Stecklein (The University of Kansas Cancer Center) and MDA-MB-436-BRCA was gifted from Dr. Johnson (Fox Chase Cancer Center). We then quantified clonogenic cell survival, gH2AX and 53BP1 foci at 24 h after irradiation, MN number and MN-cGAS co-localization (cGAS+ MN) at 24 and 74 h after irradiation, and RT-induced senescence. In vivo, we used a preclinical TNBC mouse model (4T1 tumors on the leg of BALB/c mice) to assess survival and tumor growth delay on animals treated with DMSO, PARPi alone (Olaparib, 100 mg/kg), DMSO+x-rays, and PARPi+x-rays. Experiments with protons are ongoing. PARPi was administrated via oral gavage 2 h prior to irradiation (1 × 11 Gy). Results Survival fraction was lower after protons compared to x-rays (RBED10%&gt;1) in HCC1937-BRCA, HCC1937 and MDA-MB-436 cells. Regardless of the radiation type, survival fraction was lower for HCC1937 compared to HCC1937-BRCA cells. PARPi treatment appears to result in greater radiosensitization of cells exposed to protons than those exposed to x-rays as assessed by clonogenic cell survival. The number of MN per nucleus was higher in HCC1937 than HCC1937-BRCA at 24 and 72 h after protons and x-rays at both 2 and 5 Gy, and this effect that was amplified with PARPi vs. without PARPi. Moreover, the number of cGAS+ MN was greater after protons than x-rays for HCC1937 but not HCC1937-BRCA at 24 and 72 h. The proportion of senescent cells for HCC1937-BRCA was higher (1.4 fold) after PARPi+protons compared to PARPi+x-rays. In vivo, x-rays lead to a delay in tumor growth, which was higher for the PARPi+x-rays group compared to PARPi alone or DMSO+x-rays groups. Conclusion In vitro, a PARPi treatment in BRCA1 mutated cell lines leads to a greater sensitivity to radiation compared to their counterparts with recovered BRCA1 function. This sensitivity is higher after protons compared to x-rays (survival fraction and number of micronuclei). In vivo, PARPi treatment combined with x-rays lead to higher delay in tumor growth compared to x-rays alone. These preliminary data are promising results on the effect of radiation combined with PARPi on BRCA1 mutated models.

Citation Format: Mariam Ben Kacem, Scott J. Bright, Broderick X Turner, David B Flint, Mandira Manandhar, David Martinus, Gabriel O Sawakuchi, Simona F Shaitelman. Parp inhibition sensitizes brca deficient cancer cell lines and tumors to clinical x-ray and proton irradiation [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-06-01.

Abstract P4-11-21: Plasma cytokine levels in breast cancer-related lymphedema patients

Background: Breast cancer-related lymphedema (BCRL) is encountered by approximately 40% of breast cancer survivors. BCRL drastically affects quality of life, as the arm, breast, and trunk swelling, together with pain, depression, and cellulitis risk can make everyday functions difficult or impossible. Objective: To identify plasma biomarkers that can suggest targeted pharmacological treatments for breast cancer survivors who develop lymphedema (LE). Methods: In a prospective, ongoing, longitudinal clinical study (NCT02949726), peripheral blood, perometric arm volumes, and near-infrared fluorescence lymphatic images/videos (NIRF-LI) for the first 33 enrolled advanced breast cancer patients were collected pre-mastectomy/breast-conserving surgery with ALND, four weeks postoperatively, at the end of radiation therapy (RT), and at 6 months post-RT. 29 cytokines were measured at each time point using a MILLIPLEX MAP human cytokine/chemokine magnetic bead panel from isolated blood plasma. Cytokine levels in subjects with &gt;5% perometric arm swelling at 6 months post-regional nodal RT were analyzed and compared to those with &lt;5% perometric arm swelling at 6 months post-regional nodal RT. Additionally, subjects who exhibited LE-associated dermal backflow, identified by cloudy fluid masses, instead of linear vessels, with NIRF-LI, at 6 months post-regional nodal RT were compared to those without backflow at 6 months post-regional nodal RT. GraphPad/Prism 9 non-parametric Mann-Whitney t-test was used to compute the p-values of each cytokine. P-values less than 0.05 were deemed significant. Results: Out of the 33 subjects, 7 developed &gt;5% perometric arm swelling 6 months post-regional nodal RT and 15 developed dermal backflow 6 months post-regional nodal RT. Of the 15 subjects that developed backflow, 7 also had &gt;5% perometric arm swelling. G-CSF, GM-CSF, IL-10, IL-12p40, and IL-1R-alpha were found to be significantly higher in subjects with &gt;5% perometric arm swelling at 6 months post-RT than in subjects with &lt;5% perometric arm swelling while IL-1beta was identified to be significantly lower in subjects with backflow at 6 months post-regional nodal RT than those without backflow at 6 months post-regional nodal RT. Conclusions: G-CSF, GM-CSF, IL-10, IL-12p40, IL-1Ralpha, and IL-1beta are candidate biomarkers for detecting and directing pharmacological treatment for lymphedema in breast cancer survivors.

Citation Format: Anna R Vang, Simona F Shaitelman, Eva M Sevick-Muraca, Chan Wen-yaw, John C Rasmussen, Sarah D DeSnyder, Melissa B Aldrich. Plasma cytokine levels in breast cancer-related lymphedema patients [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-21.

Abstract P4-11-18: Arm lymphatic pulsing changes after mastectomy or breast-conserving surgery with axillary lymph node dissection, detected with near-infrared fluorescence lymphatic imaging

Introduction: Axillary lymph node dissection (ALND) that accompanies mastectomy or breast-conserving surgery is assumed to disrupt arm lymphatic fluid pumping that normally flows in a one-way, distal-to-proximal path to transit cellular waste, immune cells, and large molecules to the thorax. Any resulting stagnation of lymph is surmised to drive the development of lymphedema (LE), with potential lifelong, detrimental effects on quality of life for breast cancer survivors, yet the majority of breast cancer survivors receiving ALND never encounter LE. To date, no objective before-and-after-ALND lymphatic pumping data has been published. Methods: In a prospective, ongoing, longitudinal clinical study (NCT02949726) of breast cancer patients undergoing neoadjuvant chemotherapy, axillary lymph node dissection (ALND) with mastectomy or breast-conserving surgery, and radiation treatment (RT), we used near-infrared fluorescence lymphatic imaging (NIRF-LI) to observe changes in arm lymphatics anatomy and pulsing. NIRF-LI, using a custom-built imaging system, with indocyanine green (ICG) contrast, allows “see through the skin” visualization of arm lymph pumping through lymphatic vessels, and captured videos of 58 locally advanced breast cancer patients before and approximately four weeks after mastectomy or breast-conserving surgery with ALND. Lymphatic pumping frequencies (pulses per minute) were determined from fluorescence intensity fluctuations through regions of interest (ROIs) along lymphatic vessels, quantitated with ImageJ (NIH) free software. Ipsilateral and contralateral arm dorsal, ventral, and axillary-feeding (ventral upper arm) vessel pulsing was classified as 1) static or improved to normal range (improved), or 2) transitioning to abnormal ranges (worsened) after surgery. The number of vessels in each category were tallied and reported herein. Results: After ALND, arm lymphatic pulsing frequencies improved or worsened as shown in Table 1. Conclusions: NIRF-LI allowed objective quantitation of arm lymphatic pumping frequencies captured before and after ALND accompanying mastectomy or breast-conserving surgery for breast cancer. Pulsing frequencies in detectable vessels improved in more axilla-feeding vessels, surprisingly, but worsened or did not change in more ipsilateral and ventral vessels, on both ipsilateral and contralateral sides. While cancer surgery with ALND may be associated with increased risk of BCRL, other factors, such as neoadjuvant chemotherapy, cancer severity, and radiation treatment may contribute to LE etiology.

Table 1.Anatomical position (arm)# of Vessels Improved# of Vessels WorsenedIpsilateral dorsal6499Ipsilateral ventral73107Ipsilateral axilla-feeding5626Contralateral dorsal97112Contralateral ventral8988Contralateral axilla-feeding10323

Citation Format: Melissa B Aldrich, Meghan E McWain, Wenyaw Chan, John C Rasmussen, Sarah DeSnyder, Eva M Sevick-Muraca, Simona F Shaitelman. Arm lymphatic pulsing changes after mastectomy or breast-conserving surgery with axillary lymph node dissection, detected with near-infrared fluorescence lymphatic imaging [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-18.

Outcomes After Breast Radiation Therapy in a Diverse Patient Cohort With a Germline BRCA1/2 Mutation

PURPOSE

BRCA1/2 pathogenic variant (PV) mutations confer radiation sensitivity preclinically, but there are limited data regarding breast cancer outcomes after radiation therapy (RT) among patients with documented BRCA1/2 PV mutations versus no PV mutations.

METHODS AND MATERIALS

This retrospective cohort study included women with clinical stage I-III breast cancer who received definitive surgery and RT and underwent BRCA1/2 genetic evaluation at the The University of Texas MD Anderson Cancer Center. Rates of locoregional recurrence (LRR), disease-specific death (DSD), toxicities, and second cancers were compared by BRCA1/2 PV status.

RESULTS

Of the 2213 women who underwent BRCA1/2 testing, 63% self-reported their race as White, 13.6% as Black/African American, 17.6% as Hispanic, and 5.8% as Asian/American Indian/Alaska Native; 124 had BRCA1 and 100 had BRCA2 mutations; and 1394 (63%) received regional nodal RT. The median follow-up time for all patients was 7.4 years (95% confidence interval [CI], 7.1-7.7 years). No differences were found between the groups with and without BRCA1/2 PV mutations in 10-year cumulative incidences of LRR (with mutations: 11.6% [95% CI, 7.0%-17.6%]; without mutations: 6.6% [95% CI, 5.3%-8.0%]; P = .466) and DSD (with mutations: 12.3% [95% CI, 8.0%-17.7%]; without mutations: 13.8% [95% CI, 12.0%-15.8%]; P = .716). On multivariable analysis, BRCA1/2 status was not associated with LRR or DSD, but Black/African American patients (P = .036) and Asians/American Indians/Alaska Native patients (P = .002) were at higher risk of LRR compared with White patients, and Black/African American patients were at higher risk of DSD versus White patients (P = .004). No in-field, nonbreast second cancers were observed in the BRCA1/2 PV group. Rates of acute and late grade ≥3 radiation-related toxicity in the BCRA1/2 PV group were 5.4% (n = 12) and 0.4% (n = 1), respectively.

CONCLUSIONS

Oncologic outcomes in a diverse cohort of patients with breast cancer who had a germline BRCA1/2 PV mutation and were treated with RT were similar to those of patients with no mutation, supporting the use of RT according to standard indications in patients with a germline BRCA1/2 PV mutation.

Breast Radiation Therapy-Related Treatment Outcomes in Patients With or Without Germline Mutations on Multigene Panel Testing

PURPOSE

Multigene panel testing has increased the detection of germline mutations in patients with breast cancer. The implications of using radiation therapy (RT) to treat patients with pathogenic variant (PV) mutations are not well understood and have been studied mostly in women with only BRCA1 or BRCA2 PVs. We analyzed oncologic outcomes and toxicity after adjuvant RT in a contemporary, diverse cohort of patients with breast cancer who underwent genetic panel testing.

METHODS AND MATERIALS

We retrospectively reviewed the records of 286 women with clinical stage I-III breast cancer diagnosed from 1995 to 2017 who underwent surgery, breast or chest wall RT with or without regional nodal irradiation, multigene panel testing, and evaluation at a large cancer center's genetic screening program. We evaluated rates of overall survival, locoregional recurrence, disease-specific death, and radiation-related toxicities in 3 groups: BRCA1/2 PV carriers, non-BRCA1/2 PV carriers, and patients without PV mutations.

RESULTS

PVs were detected in 25.2% of the cohort (12.6% BRCA1/2 and 12.6% non-BRCA1/2). The most commonly detected non-BRCA1/2 mutated genes were ATM, CHEK2, PALB2, CDH1, TP53, and PTEN. The median follow-up time for the entire cohort was 4.4 years (95% confidence interval, 3.8-4.9 years). No differences were found in overall survival, locoregional recurrence, or disease-specific death between groups (P > .1 for all). Acute and late toxicities were comparable across groups.

CONCLUSION

Oncologic and toxicity outcomes after RT in women with PV germline mutations detected by multigene pane testing are similar to those in patients without detectable mutations, supporting the use of adjuvant RT as a standard of care when indicated.

Association of statin use with clinical outcomes in patients with triple-negative breast cancer

BACKGROUND

Previous studies have examined the association of statin therapy and breast cancer outcomes with mixed results. The objective of this study was to investigate the clinical effects of incident statin use among individuals with triple-negative breast cancer (TNBC).

METHODS

Data from the Surveillance, Epidemiology, and End Results-Medicare and Texas Cancer Registry-Medicare databases were used, and women aged ≥66 years who had stage I, II, and III breast cancer were identified. Multivariable Cox proportional hazards regression models were used to examine the association of new statin use in the 12 months after a breast cancer diagnosis with overall survival (OS) and breast cancer-specific survival (BCSS).

RESULTS

When examining incident statin use, defined as the initiation of statin therapy in the 12 months after breast cancer diagnosis, a significant association was observed between statin use and improved BCSS (standardized hazard ratio, 0.42; 95% confidence interval [CI], 0.20-0.88; P = .022) and OS (hazard ratio, 0.70; 95% CI, 0.50-0.99; P = .046) among patients with TNBC (n = 1534). No association was observed with BCSS (standardized hazard ratio, 0.99; 95% CI, 0.71-1.39; P = .97) or OS (hazard ratio, 1.04; 95% CI, 0.92-1.17; P = .55) among those without TNBC (n = 15,979). The results were consistent when examining statin exposure as a time-varying variable.

CONCLUSIONS

Among women with I, II, and III TNBC, initiation of statin therapy in the 12 months after breast cancer diagnosis was associated with an OS and BCSS benefit. Statins may have a role in select patients with breast cancer, and further investigation is warranted.

Evaluation of overall survival and barriers to surgery for patients with breast cancer treated without surgery: a National Cancer Database analysis

Surgery remains the foundation of curative therapy for non-metastatic breast cancer, but many patients do not undergo surgery. Evidence is limited regarding this population. We sought to assess factors associated with lack of surgery and overall survival (OS) in patients not receiving breast cancer surgery. Retrospective cohort study of patients in the US National Cancer Database treated in 2004-2016. The dataset comprised 2,696,734 patients; excluding patients with unknown surgical status or stage IV, cT0, cTx, or pIS, metastatic or recurrent disease resulted in 1,192,294 patients for analysis. Chi-square and Wilcoxon rank-sum tests were used to assess differences between groups. OS was analyzed using the Kaplan-Meier method with a Cox proportional hazards model performed to assess associated factors. In total 50,626 (4.3%) did not undergo surgery. Black race, age >50 years, lower income, uninsured or public insurance, and lower education were more prevalent in the non-surgical cohort; this group was also more likely to have more comorbidities, higher disease stage, and more aggressive disease biology. Only 3,689 non-surgical patients (7.3%) received radiation therapy (RT). Median OS time for the non-surgical patients was 58 months (3-year and 5-year OS rates 63% and 49%). Median OS times were longer for patients who received chemotherapy (80 vs 50 (no-chemo) months) and RT (85 vs 56 (no-RT) months). On multivariate analysis, age, race, income, insurance status, comorbidity score, disease stage, tumor subtype, treatment facility type and location, and receipt of RT were associated with OS. On subgroup analysis, receipt of chemotherapy improved OS for patients with triple negative (HR 0.66, 95% CI 0.59-0.75, P < 0.001) and HER2+ (HR 0.74, 95% CI 0.65-0.84, P < 0.001) subgroups while RT improved OS for ER+ (HR 0.72, 95% CI 0.64-0.82, P < 0.001) and favorable-disease (ER+, early-stage, age >60) (HR 0.61, 95% CI 0.45-0.83, P = 0.002) subgroups. Approximately 4% of women with breast cancer do not undergo surgery, particularly those with more aggressive disease and lower socioeconomic status. Despite its benefits, RT was underutilized. This study provides a benchmark of survival outcomes for patients who do not undergo surgery and highlights a potential role for use of RT.

Activity-Based Costing of Intensity-Modulated Proton versus Photon Therapy for Oropharyngeal Cancer

PURPOSE

In value-based health care delivery, radiation oncologists need to compare empiric costs of care delivery with advanced technologies, such as intensity-modulated proton therapy (IMPT) and intensity-modulated radiation therapy (IMRT). We used time-driven activity-based costing (TDABC) to compare the costs of delivering IMPT and IMRT in a case-matched pilot study of patients with newly diagnosed oropharyngeal (OPC) cancer.

MATERIALS AND METHODS

We used clinicopathologic factors to match 25 patients with OPC who received IMPT in 2011-12 with 25 patients with OPC treated with IMRT in 2000-09. Process maps were created for each multidisciplinary clinical activity (including chemotherapy and ancillary services) from initial consultation through 1 month of follow-up. Resource costs and times were determined for each activity. Each patient-specific activity was linked with a process map and TDABC over the full cycle of care. All calculated costs were normalized to the lowest-cost IMRT patient.

RESULTS

TDABC costs for IMRT were 1.00 to 3.33 times that of the lowest-cost IMRT patient (mean ± SD: 1.65 ± 0.56), while costs for IMPT were 1.88 to 4.32 times that of the lowest-cost IMRT patient (2.58 ± 0.39) (P < .05). Although single-fraction costs were 2.79 times higher for IMPT than for IMRT (owing to higher equipment costs), average full cycle cost of IMPT was 1.53 times higher than IMRT, suggesting that the initial cost increase is partly mitigated by reductions in costs for other, non-RT supportive health care services.

CONCLUSIONS

In this matched sample, although IMPT was on average more costly than IMRT primarily owing to higher equipment costs, a subset of IMRT patients had similar costs to IMPT patients, owing to greater use of supportive care resources. Multidimensional patient outcomes and TDABC provide vital methodology for defining the value of radiation therapy modalities.

Five-Year Longitudinal Analysis of Patient-Reported Outcomes and Cosmesis in a Randomized Trial of Conventionally Fractionated Versus Hypofractionated Whole-Breast Irradiation

PURPOSE

There are limited prospective data on predictors of patient-reported outcomes (PROs) after whole-breast irradiation (WBI) plus a boost. We sought to characterize longitudinal PROs and cosmesis in a randomized trial comparing conventionally fractionated (CF) versus hypofractionated (HF) WBI.

METHODS AND MATERIALS

From 2011 to 2014, women aged ≥40 years with Tis-T2 N0-N1a M0 breast cancer who underwent a lumpectomy with negative margins were randomized to CF-WBI (50 Gray [Gy]/25 fractions plus boost) versus HF-WBI (42.56 Gy/16 fractions plus boost). At baseline (pre-radiation), at 6 months, and yearly thereafter through 5 years, PROs included the Breast Cancer Treatment Outcome Scale (BCTOS), Functional Assessment of Cancer Therapy-Breast (FACT-B), and Body Image Scale; cosmesis was reported by the treating physician using Radiation Therapy Oncology Group cosmesis values. Multivariable mixed-effects growth curve models evaluated associations of the treatment arm and patient factors with outcomes and tested for relevant interactions with the treatment arm.

RESULTS

A total of 287 patients were randomized, completing a total of 14,801 PRO assessments. The median age was 60 years, 37% of patients had a bra cup size ≥D, 44% were obese, and 30% received chemotherapy. Through 5 years, there were no significant differences in PROs or cosmesis by treatment arm. A bra cup size ≥D was associated with worse BCTOS cosmesis (P < .001), BCTOS pain (P = .001), FACT-B Trial Outcome Index (P = .03), FACT-B Emotional Well-being (P = .03), and Body Image Scale (P = .003) scores. Physician-rated cosmesis was worse in patients who were overweight (P = .02) or obese (P < .001). No patient subsets experienced better PROs or cosmesis with CF-WBI.

CONCLUSIONS

Both CF-WBI and HF-WBI confer similar longitudinal PROs and physician-rated cosmesis through 5 years of follow-up, with no relevant subsets that fared better with CF-WBI. This evidence supports broad adoption of hypofractionation with boost, including in patients receiving chemotherapy and in a population with a high prevalence of obesity. The associations of large breast size and obesity with adverse outcomes across multiple domains highlight the opportunity to engage at-risk patients in lifestyle intervention strategies, as well as to consider alternative radiation treatment regimens.

Cell lines of the same anatomic site and histologic type show large variability in intrinsic radiosensitivity and relative biological effectiveness to protons and carbon ions

PURPOSE

To show that intrinsic radiosensitivity varies greatly for protons and carbon (C) ions in addition to photons, and that DNA repair capacity remains important in governing this variability.

METHODS

We measured or obtained from the literature clonogenic survival data for a number of human cancer cell lines exposed to photons, protons (9.9 keV/μm), and C-ions (13.3-77.1 keV/μm). We characterized their intrinsic radiosensitivity by the dose for 10% or 50% survival (D_10% or D_50% ), and quantified the variability at each radiation quality by the coefficient of variation (COV) in D_10% and D_50% . We also treated cells with DNA repair inhibitors prior to irradiation to assess how DNA repair capacity affects their variability.

RESULTS

We found no statistically significant differences in the COVs of D_10% or D_50% between any of the radiation qualities investigated. The same was true regardless of whether the cells were treated with DNA repair inhibitors, or whether they were stratified into histologic subsets. Even within histologic subsets, we found remarkable differences in radiosensitivity for high LET C-ions that were often greater than the variations in RBE, with brain cancer cells varying in D_10% (D_50% ) up to 100% (131%) for 77.1 keV/μm C-ions, and non-small cell lung cancer and pancreatic cancer cell lines varying up to 55% (76%) and 51% (78%), respectively, for 60.5 keV/μm C-ions. The cell lines with modulated DNA repair capacity had greater variability in intrinsic radiosensitivity across all radiation qualities.

CONCLUSIONS

Even for cell lines of the same histologic type, there are remarkable variations in intrinsic radiosensitivity, and these variations do not differ significantly between photon, proton or C-ion radiation. The importance of DNA repair capacity in governing the variability in intrinsic radiosensitivity is not significantly diminished for higher LET radiation.

Delineating copy number and clonal substructure in human tumors from single-cell transcriptomes

Single-cell transcriptomic analysis is widely used to study human tumors. However, it remains challenging to distinguish normal cell types in the tumor microenvironment from malignant cells and to resolve clonal substructure within the tumor. To address these challenges, we developed an integrative Bayesian segmentation approach called copy number karyotyping of aneuploid tumors (CopyKAT) to estimate genomic copy number profiles at an average genomic resolution of 5 Mb from read depth in high-throughput single-cell RNA sequencing (scRNA-seq) data. We applied CopyKAT to analyze 46,501 single cells from 21 tumors, including triple-negative breast cancer, pancreatic ductal adenocarcinoma, anaplastic thyroid cancer, invasive ductal carcinoma and glioblastoma, to accurately (98%) distinguish cancer cells from normal cell types. In three breast tumors, CopyKAT resolved clonal subpopulations that differed in the expression of cancer genes, such as KRAS, and signatures, including epithelial-to-mesenchymal transition, DNA repair, apoptosis and hypoxia. These data show that CopyKAT can aid in the analysis of scRNA-seq data in a variety of solid human tumors.

Impact of adjuvant endocrine therapy in older patients with comorbidities and estrogen receptor-positive, node-negative breast cancer-A National Cancer Database analysis

BACKGROUND

Data are lacking about the benefit of adjuvant endocrine therapy (ET) in older patients with multiple comorbidities. The authors sought to determine the effect of ET on the survival of older patients who had multiple comorbidities and estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative, pathologic node-negative (pN0) breast cancer.

METHODS

Women aged ≥70 years in the National Cancer Database (2010-2014) with Charlson/Deyo comorbidity scores of 2 or 3 who had pathologic tumor (pT1)-pT3/pN0, ER-positive/HER2-negative breast cancer were divided into 2 cohorts: adjuvant ET and no ET. Propensity scores were used to match patients based on age, comorbidity score, facility type, pT classification, chemotherapy, surgery, and radiation therapy. A Cox proportional hazards model was used to estimate the effect of ET on overall survival (OS).

RESULTS

In the nonmatched cohort (n = 3716), 72.8% of patients received ET (n = 2705), and 27.2% did not (n = 1011). The patients who received ET were younger (mean age, 76 vs 79 years; P < .001) and had higher rates of breast conservation compared with those who did not receive ET (lumpectomy plus radiation: 43.4% vs 23.8%, respectively; P < .001). In the matched cohort (n = 1972), the median OS was higher in the ET group (79.2 vs 67.7 months; P < .0001). In the adjusted analysis, ET was associated with improved survival (hazard ratio, 0.70; 95% CI, 0.59-0.83).

CONCLUSIONS

In older patients who have pN0, ER-positive/HER2-negative breast cancer with comorbidities, adjuvant ET was associated with improved OS, which may have been overestimated given the confounders inherent in observational studies. To optimize outcomes in these patients, current standard recommendations should be considered stage-for-stage based on life expectancy and the level of tolerance to treatment.

Association of Chemotherapy With Survival in Elderly Patients With Multiple Comorbidities and Estrogen Receptor-Positive, Node-Positive Breast Cancer

Importance

Breast cancer risk and comorbidities increase with age. Data are lacking on the association of adjuvant chemotherapy with survival in elderly patients with multiple comorbidities and node-positive breast cancer.

Objective

To examine the association of chemotherapy with survival in elderly patients with multiple comorbidities and estrogen receptor-positive, node-positive breast cancer.

Design, Setting, and Participants

This retrospective cohort study included patients in the US National Cancer Database who were 70 years or older; had a Charlson/Deyo comorbidity score of 2 or 3; had estrogen receptor-positive, ERBB2 (formerly HER2 or HER2/neu)-negative breast cancer; and underwent surgery for pathologic node-positive breast cancer from January 1, 2010, to December 31, 2014. Propensity scores were used to match patients receiving adjuvant chemotherapy with those not receiving adjuvant chemotherapy based on age, comorbidity score, facility type, facility location, pathologic T and N stage, and receipt of adjuvant endocrine and radiation therapy. Data analysis was performed from December 13, 2018, to April 28, 2020.

Exposures

Chemotherapy.

Main Outcomes and Measures

The association of adjuvant chemotherapy with overall survival was estimated using a double robust Cox proportional hazards regression model.

Results

Of a total of 2 445 870 patients in the data set, 1592 patients (mean [SD] age, 77.5 [5.5] years; 1543 [96.9%] female) met the inclusion criteria and were included in the initial nonmatched analysis. Of these patients, 350 (22.0%) received chemotherapy and 1242 (78.0%) did not. Compared with patients who did not receive chemotherapy, patients who received chemotherapy were younger (mean age, 74 vs 78 years; P < .001), had larger primary tumors (pT3/T4 tumors: 72 [20.6%] vs 182 [14.7%]; P = .005), and had higher pathologic nodal burden (75 [21.4%] vs 81 [6.5%] with stage pN3 disease and 182 [52.0%] vs 936 [75.4%] with stage pN1 disease; P < .001). More patients who received chemotherapy also received other adjuvant treatments, including endocrine therapy (309 [88.3%] vs 1025 [82.5%]; P = .01) and radiation therapy (236 [67.4%] vs 540 [43.5%]; P < .001). In the matched cohort, with a median follow-up of 43.1 months (95% CI, 39.6-46.5 months), no statistically significant difference was found in median overall survival between the chemotherapy and no chemotherapy groups (78.9 months [95% CI, 78.9 months to not reached] vs 62.7 months [95% CI, 56.2 months to not reached]; P = .13). After adjustment for potential confounding factors, receipt of chemotherapy was associated with improved survival (hazard ratio, 0.67; 95% CI, 0.48-0.93; P = .02).

Conclusions and Relevance

This cohort study found that in node-positive, estrogen receptor-positive elderly patients with breast cancer and multiple comorbidities, receipt of chemotherapy was associated with improved overall survival. Despite attempts to adjust for selection bias, these findings suggest that physicians carefully selected patients likely to derive treatment benefit from adjuvant chemotherapy based on certain unmeasured variables. A standardized, multidisciplinary approach to care may be associated with long-term treatment outcomes in this subset of the population.

Outcomes with Partial Breast Irradiation vs. Whole Breast Irradiation: a Meta-Analysis

BACKGROUND

Several randomized trials have been performed comparing partial breast irradiation (PBI) and whole breast irradiation (WBI) though controversy remains, including regarding differences by PBI technique. We performed a meta-analysis to compare results between WBI versus PBI and between PBI techniques.

METHODS

A systematic review was performed to identify modern randomized studies listed in MEDLINE from 2005 to 2020. PBI trials were divided into external beam radiation and brachytherapy techniques, with intraoperative radiation excluded. A Bayesian logistic regression model evaluated the risk of ipsilateral breast tumor recurrence (IBTR) and acute and chronic toxicities. The primary outcome was IBTR at 5 years with WBI compared with PBI.

RESULTS

A total of 9758 patients from 7 studies were included (4840-WBI, 4918-PBI). At 5 years, no statistically significant difference in the rate of IBTR was noted between PBI (1.8%, 95% HPD 0.68-3.2%) and WBI (1.7%, 95% HPD 0.92-2.4%). By PBI technique, the 5-year rate of IBTR rate for external beam was 1.7% and 2.2% for brachytherapy. Rates of grade 2 + acute toxicity were 7.1% with PBI versus 47.5% with WBI. For late toxicities, grade 2/3 rates were 0%/0% with PBI compared with 1.0%/0% with WBI.

CONCLUSIONS

IBTR rates were similar between PBI and WBI with no significant differences noted by PBI technique; PBI had reduced acute toxicities compared to WBI. Because studies did not provide toxicity data in a consistent fashion, definitive conclusions cannot be made with additional data from randomized trials needed to compare toxicity profiles between PBI techniques.

Anatomy and physiology of the sentinel lymph nodes of the upper extremity: Implications for axillary reverse mapping in breast cancer

BACKGROUND

This study characterizes the physiological drainage of the normal upper extremity using single-photon emission computed tomography/computed tomography (SPECT/CT) lymphoscintigraphy axillary reverse lymphatic mapping (ARM).

METHODS

A consecutive series of patients assessed with SPECT/CT lymphoscintigraphy ARM of the upper extremity were included. Anatomical localization of the axillary sentinel lymph nodes (SLN) was completed in normal axillae in relation to consistent anatomic landmarks. Retrospective case note analysis was performed to collect patient demographic data.

RESULTS

A total of 169 patients underwent SPECT/CT lymphoscintigraphy, and imaging of 182 normal axillae was obtained. All patients (100%) had an axillary SLN identified: 19% had a single contrast-enhanced SLN in the axilla and the remainder had multiple. The SLN(s) of the upper extremity was located in the upper outer quadrant (UOQ) of the axilla in 97% of cases (177 axillae). When the SLN(s) was found in the UOQ of the axilla, second-tier lymph nodes were found predominantly in the upper inner quadrant (50% of cases).

CONCLUSIONS

The upper extremity SLN(s) is located in a constant region of the axilla. This study provides the most complete investigation to date and results can be directly applied clinically to ARM techniques and adjuvant radiation planning.

A Randomized Phase II Study of Sequential Eribulin Versus Paclitaxel Followed by FAC/FEC as Neoadjuvant Therapy in Patients with Operable HER2-Negative Breast Cancer

Lessons Learned

The combination of eribulin with 5‐fluorouracil, either doxorubicin or epirubicin, and cyclophosphamide (FAC/FEC) was not superior to the combination of paclitaxel with FAC/FEC and was associated with greater hematologic toxicity.

Eribulin followed by an anthracycline‐based regimen is not recommended as a standard neoadjuvant therapy in nonmetastatic operable breast cancer.

Background

Neoadjuvant systemic therapy is the standard of care for locally advanced operable breast cancer. We hypothesized eribulin may improve the pathological complete response (pCR) rate compared with paclitaxel.

Methods

We conducted a 1:1 randomized open‐label phase II study comparing eribulin versus paclitaxel followed by 5‐fluorouracil, either doxorubicin or epirubicin, and cyclophosphamide (FAC/FEC) in patients with operable HER2‐negative breast cancer. pCR and toxicity of paclitaxel 80 mg/m² weekly for 12 doses or eribulin 1.4 mg/m² on days 1 and 8 of a 21‐day cycle for 4 cycles followed by FAC/FEC were compared.

Results

At the interim futility analysis, in March 2015, 51 patients (28 paclitaxel, 23 eribulin) had received at least one dose of the study drug and were thus evaluable for toxicity; of these, 47 (26 paclitaxel, 21 eribulin) had undergone surgery and were thus evaluable for efficacy. Seven of 26 (27%) in the paclitaxel group and 1 of 21 (5%) in the eribulin group achieved a pCR, and this result crossed a futility stopping boundary. In the paclitaxel group, the most common serious adverse events (SAEs) were neutropenic fever (grade 3, 3 patients, 11%). In the eribulin group, nine patients (39%) had neutropenia‐related SAEs, and one died of neutropenic sepsis. The study was thus discontinued. For the paclitaxel and eribulin groups, the 5‐year event‐free survival (EFS) rates were 81.8% and 74.0% (hazard ratio [HR], 1.549; 95% confidence interval [CI], 0.817–2.938; p = .3767), and the 5‐year overall survival (OS) rates were 100% and 84.4% (HR, 5.813; 95% CI, 0.647–52.208; p = .0752), respectively.

Conclusion

We did not observe a higher proportion of patients undergoing breast conservation surgery in the eribulin group than in the paclitaxel group. The patients treated with eribulin were more likely to undergo mastectomy and less likely to undergo breast conservation surgery, but the difference was not statistically significant.

As neoadjuvant therapy for operable HER2‐negative breast cancer, eribulin followed by FAC/FEC is not superior to paclitaxel followed by FAC/FEC and is associated with a higher incidence of neutropenia‐related serious adverse events.

Consensus on Contouring Primary Breast Tumors on MRI in the Setting of Neoadjuvant Partial Breast Irradiation in Trials

PURPOSE

Our purpose was to present and evaluate expert consensus on contouring primary breast tumors on magnetic resonance imaging (MRI) in the setting of neoadjuvant partial breast irradiation in trials.

METHODS AND MATERIALS

Expert consensus on contouring guidelines for target definition of primary breast tumors on contrast-enhanced MRI in trials was developed by an international team of experienced breast radiation oncologists and a dedicated breast radiologist during 3 meetings. At the first meeting, draft guidelines were developed through discussing and contouring 2 cases. At the second meeting 6 breast radiation oncologists delineated gross tumor volume (GTV) in 10 patients with early-stage breast cancer (cT1N0) according to draft guidelines. GTV was expanded isotropically (20 mm) to generate clinical target volume (CTV), excluding skin and chest wall. Delineations were reviewed for disagreement and guidelines were clarified accordingly. At the third meeting 5 radiation oncologists redelineated 6 cases using consensus-based guidelines. Interobserver variation of GTV and CTV was assessed using generalized conformity index (CI). CI was calculated as the sum of volumes each pair of observers agreed upon, divided by the sum of encompassing volumes for each pair of observers.

RESULTS

For the 2 delineation sessions combined, mean GTV ranged between 0.19 and 2.44 cm3, CI for GTV ranged between 0.28 and 0.77, and CI for CTV between 0.77 and 0.94. The largest interobserver variation in GTV delineations was observed in cases with extended tumor spiculae, blood vessels near or markers within the tumor, or with increased enhancement of glandular breast tissue. Consensus-based guidelines stated to delineate all visible tumors on contrast enhanced-MRI scan 1 to 2 minutes after contrast injection and if a marker was inserted in the tumor to include this.

CONCLUSIONS

Expert-based consensus on contouring primary breast tumors on MRI in trials has been reached. This resulted in low interobserver variation for CTV in the context of a uniform 20 mm GTV to CTV expansion margin.

Quantitative 3-Dimensional Photographic Assessment of Breast Cosmesis After Whole Breast Irradiation for Early Stage Breast Cancer: A Secondary Analysis of a Randomized Clinical Trial

Purpose

Our purpose was to use 3-dimensional (3D) surface photography to quantitatively measure breast cosmesis within the framework of a randomized clinical trial of conventionally fractionated (CF) and hypofractionated (HF) whole breast irradiation (WBI); to identify how 3D measurements are associated with patient- and physician-reported cosmesis; and to determine whether objective measures of breast symmetry varied by WBI treatment arm or transforming growth factor β 1 (TGFβ1) status.

Methods and Materials

From 2011 to 2014, 287 women age ≥40 with ductal carcinoma in situ or early-stage invasive breast cancer were enrolled in a multicenter trial and randomized to HF-WBI or CF-WBI with a boost. Three-dimensional surface photography was performed at 3 years posttreatment. Patient-reported cosmetic outcomes were recorded with the Breast Cancer Treatment Outcome Scale. Physician-reported cosmetic outcomes were assessed by the Radiation Therapy Oncology Group scale. Volume ratios and 6 quantitative measures of breast symmetry, termed F1-6C, were calculated using the breast contour and fiducial points assessed on 3D surface images. Associations between all metrics, patient- and physician-reported cosmesis, treatment arm, and TGFβ1 genotype were performed using the Kruskal-Wallis test and multivariable logistic regression models.

Results

Among 77 (39 CF-WBI and 38 HF-WBI) evaluable patients, both patient- and physician-reported cosmetic outcomes were significantly associated with the F1C vertical symmetry measure (both P < .05). Higher dichotomized F1C and volumetric symmetry measures were associated with improved patient- and physician-reported cosmesis on multivariable logistic regression (both P ≤ .05). There were no statistically significant differences in vertical symmetry or volume measures between treatment arms. Increased F6C horizontal symmetry was observed in the CF-WBI arm (P = .05). Patients with the TGFβ1 C-509T variant allele had lower F2C vertical symmetry measures (P = .02).

Conclusions

Quantitative 3D image-derived measures revealed comparable cosmetic outcomes with HF-WBI compared with CF-WBI. Our findings suggest that 3D surface imaging may be a more sensitive method for measuring subtle cosmetic changes than global patient- or physician-reported assessments.

Proton Accelerated Partial Breast Irradiation: Clinical Outcomes at a Planned Interim Analysis of a Prospective Phase 2 Trial

PURPOSE

To perform a planned interim analysis of acute (within 12 months) and late (after 12 months) toxicities and cosmetic outcomes after proton accelerated partial breast irradiation (APBI).

METHODS AND MATERIALS

A total of 100 patients with pTis or pT1-2 N0 (≤3cm) breast cancer status after segmental mastectomy were enrolled in a single-arm phase 2 study from 2010 to 2019. The clinically determined postlumpectomy target volume, including tumor bed surgical clips and operative-cavity soft-tissue changes seen on imaging plus a radial clinical expansion, was irradiated with passively scattered proton APBI (34 Gy in 10 fractions delivered twice daily with a minimum 6-hour interfraction interval). Patients were evaluated at protocol-specific time intervals for recurrence, physician reports of cosmetic outcomes and toxicities, and patient reports of cosmetic outcomes and satisfaction with the treatment or experience.

RESULTS

Median follow-up was 24 months (interquartile range [IQR], 12-43 months). Local control and overall survival were 100% at 12 and 24 months. There were no acute or late toxicities of grade 3 or higher; no patients experienced fat necrosis, fibrosis, infection, or breast shrinkage. Excellent or good cosmesis at 12 months was reported by 91% of patients and 94% of physicians; at the most recent follow-up, these were 94% and 87%, respectively. The most commonly reported late cosmetic effect was telangiectasis (17%). The total patient satisfaction rate for treatment and results at 12 and 24 months was 96% and 100%, respectively. Patients' mean time away from work was 5 days (IQR, 2-5 days), and the median out-of-pocket cost was $700 (IQR, $100-$1600). The mean left-sided heart dose was 2 cGy (range, 0.2-75 cGy), and the mean ipsilateral lung dose was 19 cGy (range, 0.2-164 cGy).

CONCLUSIONS

Proton APBI is a maturing treatment option with high local control, favorable intermediate-term cosmesis, high treatment satisfaction, low treatment burden, and exceptional heart and lung sparing.

The Development and Treatment of Lymphatic Dysfunction in Cancer Patients and Survivors

Breast-cancer-acquired lymphedema is routinely diagnosed from the appearance of irreversible swelling that occurs as a result of lymphatic dysfunction. Yet in head and neck cancer survivors, lymphatic dysfunction may not always result in clinically overt swelling, but instead contribute to debilitating functional outcomes. In this review, we describe how cancer metastasis, lymph node dissection, and radiation therapy alter lymphatic function, as visualized by near-infrared fluorescence lymphatic imaging. Using custom gallium arsenide (GaAs)-intensified systems capable of detecting trace amounts of indocyanine green administered repeatedly as lymphatic contrast for longitudinal clinical imaging, we show that lymphatic dysfunction occurs with cancer progression and treatment and is an early, sub-clinical indicator of cancer-acquired lymphedema. We show that early treatment of lymphedema can restore lymphatic function in breast cancer and head and neck cancer patients and survivors. The compilation of these studies provides insights to the critical role that the lymphatics and the immune system play in the etiology of lymphedema and associated co-morbidities.

Optimizing MR-Guided Radiotherapy for Breast Cancer Patients

Current research in radiotherapy (RT) for breast cancer is evaluating neoadjuvant as opposed to adjuvant partial breast irradiation (PBI) with the aim of reducing the volume of breast tissue irradiated and therefore the risk of late treatment-related toxicity. The development of magnetic resonance (MR)-guided RT, including dedicated MR-guided RT systems [hybrid machines combining an MR scanner with a linear accelerator (MR-linac) or 60Co sources], could potentially reduce the irradiated volume even further by improving tumour visibility before and during each RT treatment. In this position paper, we discuss MR guidance in relation to each step of the breast RT planning and treatment pathway, focusing on the application of MR-guided RT to neoadjuvant PBI.

Exclusion of Men from Randomized Phase III Breast Cancer Clinical Trials

Male breast cancer treatment regimens are often extrapolated from female-based studies because of a paucity of literature analyzing male breast cancer. Using ClinicalTrials.gov, we analyzed breast cancer randomized clinical trials (RCTs) to determine which factors were associated with male-gender inclusion. Of 131 breast cancer RCTs identified, male patients represented 0.087% of the total study population, which is significantly less than the proportion of male patients with breast cancer in the U.S. (0.95%; p < .001). Twenty-seven trials included male patients (20.6%). Lower rates of male inclusion were seen in trials that randomized or mandated hormone therapy as part of the trial protocol compared with trials that did not randomize or mandate endocrine therapy (2.5% vs. 28.6% male inclusion; p < .001). It is imperative for breast cancer clinical trials to include men when allowable in order to improve generalizability and treatment decisions in male patients with breast cancer.

Endobronchial ultrasound-guided injection of NBTXR3 radio-enhancing nanoparticles into mediastinal and hilar lymph nodes: a swine model to evaluate feasibility, injection technique, safety, nanoparticle retention and dispersion

Background

Loco-regionally advanced lung cancer is typically treated with a combination of chemotherapy and radiation therapy, but overall survival and local control remain poor. Radio-enhancing nanoparticles such as NBTXR3 activated by radiotherapy results in increased cell death and potentially an anti-tumor immune response. The goal of this study was to assess the feasibility and safety of endobronchial ultrasound (EBUS)-guided injection of NBTXR3 into mediastinal and hilar lymph nodes (LN), as well as assess nanoparticle retention in the LN post-injection.

Methods

Animals underwent bronchoscopy under general anesthesia with EBUS-guided injection of NBTXR3 into hilar and mediastinal LN. LN and injection volumes were calculated based on pre-injection computed tomography (CT) scans. CT scans were repeated at 5 min, 30 min, and 8 days post-injection. Blood-draws were also obtained at baseline and post-injection. Animals were then housed, monitored, and sacrificed 8 days post-injection. Necropsy was then performed with gross and histologic analysis of LN.

Results

A total of 20 LN were injected in 5 pigs (4 LN per animal). Nanoparticles were retained in 100% of LN at 30 min, and 90% of LN at 8 days. Extravasation of nanoparticles was seen in 4 out of the 20 LN. There were no cases of nanoparticle embolization visible by CT in distant organs. Small air-bubbles were introduced in the targets and surrounding tissue in 3 out of 20 LN. Of note, at 8 days, none of these air-bubbles were present on CT scan. There were no intra-procedural or post-procedural complications in either CT scans or necropsy findings. Pigs remained clinically stable and neither laboratory values nor necropsy showed evidence of inflammation.

Conclusions

EBUS-guided injection of NBTXR3 radio-enhancing nanoparticles can be safely performed achieving a high rate of nanoparticle retention, low extravasation, and no visible nanoparticle embolization.

Abstract ES2-3: Guiding selection of RT approach after lumpectomy

Level I evidence supports the usage of adjuvant radiation therapy following breast conserving surgery for early stage breast cancer. Historically, this was typically delivered using standard fractionation whole breast irradiation. We will review multicenter, randomized controlled trials that support the use of hypofractionation in this setting. More recent level I data has also demonstrated excellent local control with partial breast irradiation for select, early stage breast cancers. In this educational talk we will review the local control and toxicity data for partial breast irradiation. International guidelines on the use of hypofractionated whole breast irradiation and partial breast irradiation will be discussed. We will aim to provide a framework for decision making when electing radiation technique in this setting.

Citation Format: SF Shaitelman. Guiding selection of RT approach after lumpectomy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr ES2-3.

Optimization of autogenerated chest-wall radiation treatment plans developed for postmastectomy breast cancer patients in underserved clinics

Over the past decade, several strides have been made to improve the management of breast cancer in developing countries; however, there are still obstacles present. In the area of radiation therapy, these hurdles include limited access to radiotherapy treatment and scarcity of oncology specialists. In an effort to reduce inequities in cancer care while improving patient outcomes, our research is focused on developing automated postmastectomy radiation therapy (PMRT) plans for breast cancer patients in these underserved communities that can be further improved upon through treatment planning system (TPS) specific optimization guidelines. The automated planning tool utilized algorithms integrated with Varian's Eclipse TPS. The tool created PMRT plans that used monoisocentric tangents and supraclavicular (SCV) fields with a mix of high and low energy photon beams along with field-in-field (FIF) segments. The completed autogenerated PMRT plans were imported into Phillip's Pinnacle 9.10 and Varian's Eclipse 13.6 TPSs to be further improved through manual optimization; the time required to complete this step was measured and assessed. A senior dosimetrist, physicist, and physician evaluated the optimized plans for clinical acceptability. Guidelines were developed for the planning systems that can be implemented by personnel with either limited experience in radiation treatment planning or those with limited time to produce treatment plans. The autogenerated plans in conjunction with our guidelines have shown to significantly reduce the time required to produce a clinically acceptable PMRT plan from approximately 120 ± 60 minutes to just 13 ± 11 (Pinnacle) and 12 ± 7 (Eclipse) minutes, reducing the total uninterrupted treatment planning time by an average of 108 ± 51 minutes. The results from this research indicate that the autogenerated PMRT plans along with the optimization guidelines are a viable option to provide quality and clinically acceptable PMRT plans that are more efficient and consistent for postmastectomy breast cancer patients in severely underserved communities.

Effect of Surgeon Factors on Long-Term Patient-Reported Outcomes After Breast-Conserving Therapy in Older Breast Cancer Survivors

BACKGROUND

The effect of surgeon factors on patient-reported quality-of-life outcomes after breast-conserving therapy (BCT) is unknown and may help patients make informed care decisions.

METHODS

We performed a survey study of women aged ≥ 67 years with non-metastatic breast cancer diagnosed in 2009 and treated with guideline-concordant BCT, to determine the association of surgeon factors with patient-reported outcomes. The treating surgeon was identified using Medicare claims, and surgeon factors were identified via the American Medical Association Physician Masterfile. The primary outcome was patient-reported cosmetic satisfaction measured by the Cancer Surveillance and Outcomes Research Team (CanSORT) Satisfaction with Breast Cosmetic Outcome instrument, while secondary outcomes included BREAST-Q subdomains. All patient, treatment, and surgeon covariables were included in a saturated multivariable linear regression model with backward elimination applied until remaining variables were p < 0.1.

RESULTS

Of 1650 women randomly selected to receive the questionnaire, 489 responded, of whom 289 underwent BCT. Median age at diagnosis was 72 years and the time from diagnosis to survey was 6 years. The mean adjusted CanSORT score was higher for patients treated by surgical oncologists than patients treated by non-surgical oncologists (4.01 [95% confidence interval [CI] 3.65-4.38] vs. 3.53 [95% CI 3.28-3.77], p = 0.006). Similarly, mean adjusted BREAST-Q Physical Well-Being (91.97 [95% CI 86.13-97.80] vs. 83.04 [95% CI 80.85-85.22], p = 0.006) and Adverse Radiation Effects (95.28 [95% CI 91.25-99.31] vs. 88.90 [95% CI 86.23-91.57], p = 0.004) scores were better among patients treated by surgical oncologists.

CONCLUSIONS

Specialized surgical oncology training is associated with improved long-term patient-reported outcomes. These findings underscore the value of specialized training and may be useful to patients choosing their care team.