Reporting of Race and Hispanic Ethnicity in Breast Cancer Studies From the National Cancer Database

This cohort study characterizes the inclusion of Hispanic ethnicity or ethnoracial categories in breast cancer studies from the National Cancer Database.

Consensus Quality Measures and Dose Constraints for Breast Cancer from the Veterans Affairs Radiation Oncology Quality Surveillance Program and American Society for Radiation Oncology (ASTRO) Expert Panel

INTRODUCTION

Using evidence-based radiation therapy to direct care for patients with breast cancer is critical to standardizing practice, improving safety, and optimizing outcomes. To address this need, the Veterans Affairs (VA) National Radiation Oncology Program (NROP) established the VA Radiation Oncology Quality Surveillance Program (VAROQS) to develop clinical quality measures (QM). The VA NROP contracted with the American Society for Radiation Oncology (ASTRO) to commission five Blue-Ribbon Panels for breast, lung, prostate, rectal, and head & neck cancers.

METHODS

The Breast Cancer Blue-Ribbon Panel experts worked collaboratively with NROP to develop consensus QM for use throughout the VA system. establishing a set of quality measures for patients in several areas including: 1) consultation and work up, 2) simulation, treatment planning and treatment, and 3) follow up care. As part of this initiative, consensus dose volume histogram (DVH) constraints were outlined.

RESULTS

In total, 36 quality measures were established. Herein we review the process utilized to develop QM and final consensus QM pertaining to all aspects of radiation patient care as well as DVH constraints.

CONCLUSIONS

The QM and expert consensus DVH constraints are intended for ongoing quality surveillance within the VA system, centers providing community care for Veterans, and also available for use by the greater non-VA community measures of quality care for breast cancer patients receiving radiation.

Modified Radical Mastectomy in De Novo Stage IV Inflammatory Breast Cancer

BACKGROUND

There are few studies on surgical management in patients with de novo metastatic inflammatory breast cancer (IBC). The objective of this study is to examine the association between modified radical mastectomy (MRM) and disease-specific survival (DSS) in patients with de novo stage IV IBC.

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Result Program was queried for patients ≥18 years old with cT4d/pT4d pathology, histology type 8530 and 8533 with distant disease between 2010 and 2016. The sample was divided into two groups: (1) the MRM group, defined as MRM or mastectomy with at least ten lymph nodes removed, and (2) the no-surgery group. Sociodemographic and clinical variables were compared between the groups on bivariable analysis. After propensity score matching, Kaplan-Meier curves and a Cox proportional-hazards model examined DSS.

RESULTS

1293 patients were included in the study, of whom 240 underwent MRM. A higher percentage in the MRM group had only one metastatic site (69.8% versus 52.2%), received chemotherapy (88.3% versus 66.1%) and radiation (58.8% versus 26.0%) compared with the no-MRM group. MRM was associated with an increase in DSS compared with no MRM [HR 0.63 (95% CI 0.50-0.80), p < 0.001]. Patients with MRM had a 5-year DSS rate of 31.4% compared with 17.7% for patients not undergoing surgery (p = 0.001). Survival time was 38 months (range 27-45 months) for the MRM group versus 27 months (22-29 months) for the no-MRM group.

CONCLUSION

MRM in patients with de novo metastatic IBC may improve DSS in a subset of patients.

NRG-BR002: A phase IIR/III trial of standard of care systemic therapy with or without stereotactic body radiotherapy (SBRT) and/or surgical resection (SR) for newly oligometastatic breast cancer (NCT02364557)

1007

Background: Prospective and retrospective studies of patients (pts) with oligometastatic (OM) disease have supported that metastases (mets) directed treatment (MDT) with SBRT or SR in addition to standard of care systemic therapy (SOC ST) can improve progression-free (PFS) and overall survival (OS) compared with SOC ST alone. However, randomized evidence in oligometastatic breast cancer (OMBC) are lacking. NRG-BR002, a randomized Phase IIR/III trial, sought to determine the efficacy of SOC ST + MDT (SBRT or SR) as first line treatment of OMBC. Methods: OMBC pts with ≤ 4 extracranial mets on standard imaging with controlled primary disease were eligible if on first line SOC ST for ≤ 12 months without progression. Pts were randomized (1:1) to ARM 1 – SOC ST (mainly chemotherapy, endocrine therapy, anti-HER2) or ARM 2 – SOC ST with MDT of all mets. Stratification included mets number (1 vs > 1), ER/PR and Her2 status, and chemotherapy use. Phase IIR targeted sample size was 128 total/116 eligible pts, for 92% power and 1-sided significance level = 0.15 to determine if adding MDT shows a signal for improved PFS (hazard ratio [HR] = 0.55, corresponding to median PFS (mPFS) from 10.5 to 19 months), in order to continue to the full phase III trial for OS. PFS and OS were estimated by Kaplan-Meier and arms compared with log-rank. Results: 125 of the 129 pts randomized were eligible (ARM 1 = 65, ARM 2 = 60). Key characteristics included median age 54, 79% ER+ or PR+/HER2-, 13% HER2+, 8% triple negative. 60% had 1 metastasis and 20% presented synchronously with primary disease. Following randomization, systemic therapy was delivered to 95% in ARM 1 and 93% in ARM 2; ablation: SBRT 93%, SR 2%, and 5% none. The median follow-up was 30 mo. The mPFS (70% CI) in ARM 1 was 23 mo (18, 29) and 19.5 mo (17, 36) in ARM 2; 24 and 36-mo PFS (70% CI) for ARM 1 were 45.7% (38.9, 52.5) and 32.8% (26.0, 39.5) compared with 46.8 (39.2, 54.3) and 38.1 (29.7, 46.6) in ARM 2; HR (70% CI): 0.92 (0.71, 1.17); and 1-sided log-rank p = 0.36. As PFS did not show signal, OS reporting is included: median OS was not reached in either arm; 36-mo OS (95% CI) in ARM 1 71.8% (58.9, 84.7) and ARM 2 68.9% (55.1, 82.6; 2-sided log-rank p = 0.54). Analysis of first failure showed new mets outside index area (Arm 1) /RT field (Arm 2) developed similarly in both arms at 40%. There were fewer new mets inside treated/index area for Arm 2 6.7% vs ARM 1 29.2%, respectively. There were no grade 5 treatment-related adverse events (AEs), 1 grade 4 AE in ARM 1, and 9.7% and 5.3% grade 3 AEs in ARMS 1 and 2, respectively. Circulating tumor cell counts (0 vs ≥1) at baseline were similar in both arms and were not prognostic HR (95% CI): 1.04 (0.54, 2.02). Conclusions: The addition of MDT to SOC ST did not show signal for improved PFS, nor OS difference in patients with OMBC. The trial will not proceed to the Phase III component. Clinical trial information: NCT02364557.

Abstract P3-19-17: Radiation of the low axilla in the prone position

Background: Whole breast irradiation (WBI) after a positive sentinel lymph node biopsy (SNB) is recommended to be treated in the supine position to facilitate inclusion of the low axilla with “high tangents” when regional nodal irradiation is not planned. Treatment in the prone position has several advantages over supine positioning including minimizing heart and lung doses for many and decreased skin toxicity for larger breasted women. We hypothesized that, using three dimensional conformal radiation therapy (3DCRT), the low axilla can be safely and adequately treated in the prone position with minimal toxicity and good outcomes. Methods: We identified patients who underwent post lumpectomy whole breast and low axilla irradiation in the prone position using 3DCRT from 2014 to 2020. Standard 3DCRT treatment planning included delineation of surgical cavity, breast and low axillary clinical target volumes (CTV) with 5 mm expansion to planning target volumes (PTV). The “low axilla” CTV was generally defined as the level I axilla according to the RTOG Breast Cancer Atlas. Dosimetric data for both targets and organs at risk (OARs) was extracted from approved treatment plans’ dose-volume histograms (DVHs). Toxicity and cancer outcomes were collected from the electronic medical records. Descriptive statistical analysis was performed. Results: Seventy patients were identified. Median age was 61 years (range 34-87), median body mass index (BMI) was 30.4 kg/m2 (range 22.1-49.1), and 88.6% (N=62) had hormone sensitive, HER2 negative breast cancer. The median tumor size was 1.35 cm (range 0.07-4.5cm). For 56 patients (80.0%), a SNB was done with median of 2 (range 1-7) sentinel nodes removed - 19 (34%) with macro-metastasis (median size 4 mm, range 2.2-13mm), 21 (37.5%) with micrometastasis, and 16 (28.6%) with isolated tumor cells. Three patients had an additional node with isolated tumor cells. Thirteen (18.6%) were Nx (no nodal evaluation) and 1 had an unsuccessful SLNB with no lymph nodes obtained. Hypofractionation was used in 97.1% (N=68): 4256 cGy in 16 fractions (N=44, 62.8%) or 4000 cGy in 15 fractions (N=24, 34.3%). All targets were covered adequately. The median V95/V90 of the PTVbreast_eval, PTVlump_eval, and PTVAx were 96%/98.3% (range 76.2/91.9% - 99.6/101.4%), 100.1%/101.2% (range 87.6/94.9%-102.8/103.3%), and 95.3%/97.5% (range 82.4/91.6%-100.4/101.7%) respectively. The mean heart dose for all patients was 83.5 cGy; 82.7 cGy for right-sided tumors and 83.8 cGy for left-sided tumors. The median V16 of the ipsilateral lung was 4.25% (range 0.2 - 11.3%). Overall, toxicity was low with no grade 3 or higher events. For acute toxicity, most patients (N=54, 77.1%) reported grade 1 fatigue and had either grade 1 (N=52, 74.2%) or grade 2 (N=15, 21.4%) dermatitis. For late toxicity, 14 patients (20%) were referred to physical therapy after radiation, 7 (10%) for range of motion, 5 (7%) for arm lymphedema evaluation and 4 (6%) for other reasons. With a median follow-up of 18.5 months (range 0-63 months), 1 patient recurred both locally and regionally (1.4%) and one other patient recurred distantly. Conclusions: Patients with a positive SNB or are Nx who are recommended to have post-lumpectomy whole breast and low axilla irradiation can be safely and adequately treated in the prone position using 3DCRT with minimal toxicity and good outcomes.

Citation Format: Victoria Doss, Erin Healy, Sasha Beyer, Sachin R. Jhawar, Jose G. Bazan, Julia White. Radiation of the low axilla in the prone position [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 P3-19-17.

Abstract P3-19-08: Breast cancer related lymphedema in patients undergoing RNI: Is the axillary lateral vessel thoracic junction an organ-at-risk?

Background: Breast-cancer related lymphedema (BCRL) is a devastating treatment complication driven by the extent of axillary surgery (axillary lymph node dissection [ALND] versus sentinel lymph node biopsy [SLNB]). Regional nodal irradiation (RNI) may increase the risk of BCRL by up to 5%. Recently, investigators identified a region of the axilla known as the axillary-lateral thoracic vessel juncture (ALTJ) as a potential organ-at-risk (OAR) demonstrating that increasing radiation dose to the ALTJ was associated with a higher risk of BCRL. Here, we set to validate whether radiation dose to the ALTJ is associated with BCRL. Materials/Methods: We identified patients with stage II-III breast cancer treated with adjuvant RNI after M or L from 2013-2018 excluding those with BCRL pre-radiation. RNI treatment planning included delineation of clinical target volumes (CTVs): breast or chest wall and regional lymph nodes per the RTOG Breast Cancer Atlas. The CTVs were expanded by 5mm to create the planning target volume (PTV). Dose delivered was 50 Gy/25 fractions with goal of 47.5 Gy (95%) to 95% of each PTV. We defined BCRL as difference in arm circumference between the ipsilateral and contralateral limb &gt;2.5 cm at any 1 visit or ≥2 cm on at least 2 visits. All patients suspected of having BCRL at routine follow-up visits were evaluated by physical therapy. The ALTJ was retrospectively contoured and the following metrics collected: maximum/minimum/mean dose; V10Gy-V50Gy. Follow-up time was defined as the time from surgery to the development of BCRL or last follow-up. Cox proportional hazards regression models were used to test the association between clinical and dosimetric parameters with the development of BCRL. All variables with p&lt;0.10 on univariate analysis were entered in the final multivariate model (p&lt;0.05 considered statistically significant). Results: Population includes 378 patients with median age 53 years (interquartile range [IQR], 45-61 years), median body mass index (BMI) 28.4 kg/m2 (IQR, 24.3-33.4 kg/m2), 60% HR+/HER2-, 89% chemotherapy, 53% stage III, 71% underwent M, and 82% underwent ALND with median of 18 nodes removed (IQR, 11-25) and median of 2+ nodes (IQR, 1-5). Median follow-up time was 54.5 months (IQR, 40.3-72.2 months). The ALTJ and axilla PTV overlapped in 91% of the patients. BCRL developed in 97 patients (25.7%) at a median of 18.9 months (IQR, 9.9-30.6 months). The 4-year cumulative incidence of BCRL was 23.5% (26.6% ALND vs. 8.7% SLNB, p=0.002). On univariate analysis, increasing age (HR=1.02, p=.039), increasing BMI (HR=1.04, p=0.002), increasing number of nodes removed (HR=1.04, p&lt;0.0001), and use of IMRT vs. 3DCRT (HR=1.50, p=0.041) were all significantly associated with developing BCRL while increasing size of the axilla PTV (HR=0.96, p=0.047) was associated with a lower risk. None of the ALTJ metrics were associated with developing BCRL. Increasing ALTJ V45 was marginally associated with a lower risk of BCRL (HR=0.96, p=0.091). On multivariate analysis, increasing age (HR=1.02, p=0.021), increasing BMI (HR=1.04, p=0.004), and increasing number of nodes removed (HR=1.03, p=0.001) were associated with a higher risk of developing BCRL while use of IMRT (HR=1.24, p=0.338), size of the axilla PTV (HR=0.96, p=0.110) and ALTJ V45 (HR=0.99, p=0.708) were not. There were 10 local-regional recurrence (LRR) events as a first failure, 8 of which occurred with simultaneous distant metastases (DM). Of these LRRs, 5 included an axillary nodal component (all with DM) resulting in a 2.6% 4-year LRR rate (1.4% axillary recurrence rate). Conclusion: In this analysis, ALTJ is not validated as a critical OAR for reducing BCRL risk. Until such an OAR is discovered, the axillary PTV should not be modified or dose reduced in efforts to reduce BCRL given the low LRR and inability to validate ALTJ as an OAR.

Citation Format: Erin Healy, Sachin Jhawar, Sasha Beyer, Julia R White, Jose G Bazan. Breast cancer related lymphedema in patients undergoing RNI: Is the axillary lateral vessel thoracic junction an organ-at-risk? [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 P3-19-08.

Abstract P3-19-09: Impact of intraoperative radiation therapy and external beam radiation therapy on non-breast cancer mortality in early-stage breast cancer

Purpose: The TARGIT-A trial of kilovoltage intraoperative radiation therapy (IORT) versus external beam radiation therapy (EBRT) demonstrated a significant reduction in non-breast cancer mortality (nBCM) in women that received IORT, largely attributed to an increase in cardiac mortality in patients that received EBRT. Further, If EBRT does result in excess nBCM due to cardiac or other causes, then treatment with lumpectomy (Lump) alone or mastectomy (Mast) alone should result in lower rates of nBCM rates compared to Lump+EBRT. Our primary objective was to determine whether Lump+EBRT results in increased nBCM compared to Lump+IORT in women with early-stage breast cancer (BC) with a hypothesis that the two approaches should result in equivalent nBCM. We also tested the hypotheses that Lump+EBRT should have the same rates of nBCM as Lump alone or Mast alone. Materials/Methods: We used the Surveillance Epidemiology and End Results (SEER) database to identify women with early-stage BC treated with Lump alone, Lump+EBRT, Lump+IORT, or Mast alone from 2000-2016. SEER does not distinguish between kilovoltage IORT and electron IORT. We included patients with characteristics similar to the TARGIT-A study: age≥45 years; ductal carcinoma in situ (DCIS) or T1; lymph-node negative. We excluded patients that: received chemotherapy; received postmastectomy radiation therapy; had unknown cause of death; and had ≤1 month of follow-up. The primary endpoint was nBCM which is captured in the SEER database (patients were censored if they were alive or dead due to cancer at last follow-up). Cox-proportional hazards multivariate regression models were used to compare nBCM between Lump+EBRT and Lump+IORT adjusting for confounders that were statistically significant on univariate analysis. We secondarily compared nBCM in the Lump+EBRT vs. Lump population and Lump+EBRT vs. Mast population. Results: We identified 219,470 women that met the inclusion criteria: 121,776 Lump+EBRT; 1,735 Lump+IORT; 41,900 Lump; 54,059 Mast. Median follow-up time was 61 months for the entire cohort (IQR, 30-99 months) but was shorter for Lump+IORT patients (29 months) compared to the other groups (63 months Lump+EBRT; 62 months Mast; 57 months Lump). There were a total of 16,640 nBCM events: 6,210 Lump+EBRT; 5,708 Lump; 4,704 Mast; 18 Lump+IORT. The 5-year cumulative incidence of nBCM was 3.1% for Lump+EBRT vs. 1.6% for Lump+IORT (p=0.034). After adjustment for potential confounders (age, tumor location, marital status, race/ethnicity, DCIS vs. invasive, tumor grade, hormone receptor status, and receipt of axillary surgery), patients treated with Lump+IORT had a 38% relative reduction in the risk of nBCM compared to those treated with Lump+EBRT (HR=0.62, 95% CI 0.39-0.99, p=0.045). Other factors associated with increased nBCM included older age, divorced/single/widowed status (vs. married), Black race, high tumor grade, receipt of axillary lymph node dissection (vs. sentinel lymph node biopsy), no axillary surgery (vs. sentinel node biopsy), and ER-/PR- disease (vs. ER+ or PR+). In contrast, patients treated with Lulmp+EBRT had lower nBCM compared to those that received Lump alone (adjusted HR=0.55, 95% CI 0.53-0.57, p&lt;0.0001) and compared to those that received Mast alone (adjusted HR=0.59, 95% CI 0.56-0.61, p&lt;0.0001). Conclusion: In summary, contrary to our hypothesis, we found that Lump+IORT was associated with lower nBCM compared to Lump+EBRT possibly reflecting underlying selection bias. However, Lump+EBRT was not associated with an increased nBCM relative to patients treated with Lump alone or Mast alone. This suggests that the underlying mechanism for the reduced nBCM seen in patients treated with IORT in the TARGIT-A trial and this SEER analysis is not due to the potentially harmful effects of EBRT.

Citation Format: Jose G Bazan, Jay Fisher, Sachin Jhawar, Erin Healy, Sasha Beyer, Julia R. White. Impact of intraoperative radiation therapy and external beam radiation therapy on non-breast cancer mortality in early-stage breast cancer [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 P3-19-09.

Abstract P3-19-02: Should deep inspiration breath hold scans be standardly acquired for right-sided breast/chestwall and regional nodal irradiation?

Background: Adjuvant regional nodal irradiation (RNI) after breast conserving surgery or mastectomy is supported by clinical trials for patients with node-positive breast cancer. RNI results in increased radiation dose to organs-at-risk (OARs) such as the heart and lungs. While regular acquisition of both free breathing (FB) and deep inspiration breath hold (DIBH) scans has been widely adopted for left-sided breast cancers (LBCs) as a cardiac-sparing technique, DIBH scans are not routinely acquired for right-sided breast cancers (RBCs). Therefore, when OAR constraints cannot be met with 3D conformal radiation therapy (3DCRT) planning on the FB scan, the only option is intensity modulated radiation therapy (IMRT), with its inherent increased cost, resource utilization, and requirement for insurance authorization. Given these challenges, we have regularly acquired FB and DIBH scans for right-sided RNI since 2018. We hypothesized that acquisition of DIBH scans would result in a reduced need for IMRT and reduced dose to OARs. Methods: We retrospectively identified patients who were treated with right-sided RNI who had both FB and DIBH scans. All patients had target volumes (breast or chest wall and regional lymph nodes [undissected axillary, supraclavicular, and internal mammary nodes]) prospectively contoured on the FBCT scan based upon the RTOG Breast Atlas. This initiated a treatment planning algorithm that began with creating a FB 3DCRT plan and changed to DIBH 3DCRT then FB IMRT when OAR constraints could not be met while maintaining acceptable planning target volume (PTV) coverage. For patients who did not have contours available on the DIBH scan, the treating physician retrospectively completed the PTV contours. For each patient, three total plans were created for comparison using our institutional target coverage and OAR metrics: FB 3DCRT, FB IMRT, and DIBH 3DCRT. We compared PTV coverage and doses to multiple OARs including the contralateral breast, esophagus, heart, lungs (left, right, total lung dose), and liver. PTV coverage and OAR doses were evaluated by a one-way ANOVA followed by Bonferroni comparison. A p &lt; 0.05 was considered statistically significant.Results: We identified 38 patients in whom FB and DIBH scans were acquired. Only 32% (N=12) were treated with the standard FB 3DCRT. Of the remaining 26 patients 73% (N=19) were treated DIBH 3DCRT, and only 27% (N=7) were treated with FB IMRT, resulting in a FB IMRT rate of 18% overall. Without DIBH scans, 68% (N=19) would have advanced to FB IMRT. Dosimetric comparison across these 38 patients (N=114 plans) demonstrated that DIBH 3DCRT had at least equivalent OAR metrics as compared to FB 3DCRT, with significant improvement in max heart dose (9.6 Gy vs. 14.9 Gy; p = 0.034), right lung V20 (32.1% vs 37.8%; p &lt; 0.01), mean total lung dose (8.9 Gy vs. 10.5 Gy; p &lt; 0.01), and mean liver dose (1.8 Gy vs. 4.0 Gy; p &lt; 0.01). FB IMRT plans resulting in significantly lower right lung V20 (26.3% FB IMRT vs. 37.8% FB 3DCRT vs. 32.1% DIBH 3DCRT), but resulted in higher dose to the heart and contralateral breast: mean heart dose (2.2 Gy FB IMRT vs. 1.0 Gy FB 3DCRT vs. 0.9 Gy DIBH 3DCRT; p &lt; 0.01), maximum heart dose (16.4 Gy FB IMRT vs. 14.9 Gy FB 3DCRT vs. 9.6 Gy DIBH 3DCRT; p &lt; 0.01) and contralateral breast D5% (5.0 Gy FB IMRT vs. 2.9 Gy FB 3DCRT vs. 3.0 Gy DIBH 3DCRT; p &lt; 0.01).Conclusions: We found that acquiring DIBH scans for RBC patients receiving RNI reduced the need for FB IMRT from 68% to 18%. As compared to FB 3DCRT, DIBH 3DCRT resulted in in equivalent target coverage with significantly lower lung and liver doses. FB IMRT is useful to keep the right lung V20 within acceptable limits at the expense of higher dose to other OARs. Our data support the routine acquisition of DIBH scans in RBC patients undergoing RNI in order to decrease the proportion of patients that require FB IMRT.

Citation Format: Sachin R Jhawar, Kylee Lindsey, Karla Kuhn, Kayla Tedrick, Ian Zoller, William Taylor, Eric Cochran, Erin Healy, Sasha Beyer, Julia White, Jose G Bazan. Should deep inspiration breath hold scans be standardly acquired for right-sided breast/chestwall and regional nodal 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 P3-19-02.

Lack of Cardiotoxicity Endpoints in Prospective Trials Involving Chest Radiation Therapy: A Review of Registered, Latter-Phase Studies

BACKGROUND

Chest radiation therapy (RT) has been associated with increased cardiac morbidity and mortality in numerous studies including the landmark Darby study published in 2013 demonstrating a linear increase in cardiac mortality with increasing mean heart radiation dose. However, the extent to which cardiotoxicity has been incorporated as an endpoint in prospective RT studies remains unknown.

METHODS

We queried clincaltrials.gov to identify phase II/III trials in lung, esophageal, lymphoma, mesothelioma, thymoma, or breast cancer from 1/1/2006-2/1/2021 enrolling greater than 100 patients wherein chest RT was delivered in at least one treatment arm. The primary endpoint was the rate of inclusion of cardiotoxicity as a specific primary or secondary endpoint in the pre- (enrollment started prior to 1/1/2014) versus post-Darby era using the Chi-square test (p<0.05 considered significant). We also analyzed clinical trial factors associated with the inclusion of cardiotoxicity as an endpoint using logistic regression analysis.

RESULTS

In total, 1,822 trials were identified, of which 256 merited inclusion. 32% were for esophageal, 31% lung, 28% breast, and 7% lymphoma/thymoma/mesothelioma cancers, respectively. 5% (N=13) included cardiotoxicity as an endpoint: 6 breast cancer, 3 lung cancer, 3 esophageal cancer, and 1 lymphoma study. There was no difference in the inclusion of cardiotoxicity endpoints in the pre-Darby versus post-Darby era (3.9% vs. 5.9%, P=0.46). The greatest absolute increase in inclusion of cardiotoxicity as an endpoint was seen for lung cancer (0% vs. 6%, p=0.17) and breast cancer (5.7% vs. 10.8%, p=0.43) studies, though these increases remained statistically non-significant. We found no clinical trial factors associated with the inclusion of cardiotoxicity as an endpoint.

CONCLUSIONS

Among prospective trials involving chest RT, cardiotoxicity remains an uncommon endpoint despite its prevalence as a primary source of toxicity following treatment. In order to better characterize cardiac toxicities, future prospective studies involving chest RT should include cardiotoxicity endpoints.

Disparate Use of Chemoradiation in Elderly Patients With Localized Anal Cancer

BACKGROUND

The incidence of squamous cell carcinoma of the anus (SCCA) is increasing, particularly among the elderly (age ≥65 years). We sought to compare patterns of care for the treatment of SCCA in elderly versus nonelderly patients.

METHODS

Data for patients with stages I-III SCCA diagnosed from 2004 through 2015 were obtained from the National Cancer Database. Patients were categorized as having received standard-of-care (SOC) chemoradiation (CRT) with multiagent chemotherapy, non-SOC therapy, palliative therapy, or no treatment. Differences in treatment groups were tested using the chi-square test. We used logistic regression to identify predictors of SOC CRT and multiagent versus single-agent chemotherapy in patients receiving CRT. Propensity score matching was used to compare overall survival (OS) in elderly patients receiving multiagent versus single-agent chemotherapy for those receiving CRT.

RESULTS

We identified 9,156 elderly and 17,640 nonelderly patients. A lower proportion of elderly versus nonelderly patients (54.5% vs 65.0%; P<.0001) received SOC CRT than other treatments or no treatment. In multivariate analysis, elderly patients were 38% less likely than nonelderly patients to receive SOC CRT (odds ratio, 0.62; 95% CI, 0.58-0.65; P<.0001). A higher proportion of the elderly were treated with single-agent versus multiagent chemotherapy (16.9% vs 11.8%; P<.0001), which resulted in a >1.5-fold increase in the likelihood of elderly patients receiving single-agent chemotherapy (odds ratio, 1.52; 95% CI, 1.39-1.66) in multivariate analysis. After propensity score matching, 3-year OS was higher in elderly patients who received CRT with multiagent versus single-agent chemotherapy (77.1% vs 67.5%; hazard ratio, 0.78; 95% CI, 0.68-0.89; P=.0002).

CONCLUSIONS

In this comprehensive study of patients with stages I-III SCCA, elderly patients were less likely than nonelderly patients to receive SOC CRT. The low proportion of elderly patients receiving SOC CRT with multiagent chemotherapy for localized anal cancer suggests that the optimal treatment approach for this vulnerable population remains undefined.

De-escalation of radiation therapy in patients with stage I, node-negative, HER2-positive breast cancer

In the modern era, highly effective anti-HER2 therapy is associated with low local-regional recurrence (LRR) rates for early-stage HER2+ breast cancer raising the question of whether local therapy de-escalation by radiation omission is possible in patients with small-node negative tumors treated with lumpectomy. To evaluate existing data on radiation omission, we used the National Cancer Database (NCDB) to test the hypothesis that RT omission results in equivalent overall survival (OS) in stage 1 (T1N0) HER2+ breast cancer. We excluded patients that received neoadjuvant systemic therapy. We stratified the cohort by receipt of adjuvant radiation. We identified 6897 patients (6388 RT; 509 no RT). Patients that did not receive radiation tended to be ≥70 years-old (odds ratio [OR] = 3.69, 95% CI: 3.02-4.51, p < 0.0001), to have ≥1 comorbidity (OR = 1.33, 95% CI: 1.06-1.68, p = 0.0154), to be Hispanic (OR = 1.49, 95% CI: 1.00-2.22, p = 0.049), and to live in lower income areas (OR = 1.32, 95% CI: 1.07-1.64, p = 0.0266). Radiation omission was associated with a 3.67-fold (95% CI: 2.23-6.02, p < 0.0001) increased risk of death. While other selection biases that influence radiation omission likely persist, these data should give caution to radiation omission in T1N0 HER2+ breast cancer.

Analysis of Radiation Dose to the Shoulder by Treatment Technique and Correlation With Patient Reported Outcomes in Patients Receiving Regional Nodal Irradiation

Background/Purpose

Shoulder/arm morbidity is a late complication of breast cancer treatment with surgery and regional nodal irradiation (RNI). We set to analyze the impact of radiation technique [intensity modulated radiation therapy (IMRT) or 3D conformal radiation therapy (3DCRT)] on radiation dose to the shoulder with a hypothesis that IMRT use results in smaller volume of shoulder receiving radiation. We explored the relationship of treatment technique on long-term patient-reported outcomes using the quick disabilities of the arm, shoulder, and hand (q-DASH) questionnaire.

Materials/Methods

We identified patients treated with adjuvant RNI (50 Gy/25 fractions) from 2013 to 2018. We retrospectively contoured the shoulder organ-at-risk (OAR) from 2 cm above the ipsilateral supraclavicular (SCL) planning target volume (PTV) to the inferior SCL PTV slice and calculated the absolute volume of shoulder OAR receiving 5–50 Gy (V5–V50). We identified patients that completed a q-DASH questionnaire ≥6 months from the end of RNI.

Results

We included 410 RNI patients: 54% stage III, 72% mastectomy, 35% treated with IMRT. IMRT resulted in significant reductions in the shoulder OAR volume receiving 20–50 Gy vs. 3DCRT. In total, 82 patients completed the q-DASH. The mean (SD) q-DASH=25.4 (19.1) and tended to be lower with IMRT vs. 3DCRT: 19.6 (16.4) vs. 27.8 (19.8), p=0.078.

Conclusion

We found that IMRT reduces radiation dose to the shoulder and is associated with a trend toward reduced q-DASH scores ≥6 months post-RNI in a subset of our cohort. These results support prospective evaluation of IMRT as a technique to reduce shoulder morbidity in breast cancer patients receiving RNI.

Abstract PS15-04: De-escalation of radiation therapy in patients with stage I, node-negative, HER2-positive breast cancer: Patterns of care and survival outcomes using the national cancer database

Background: In the modern era, highly effective anti-HER2 therapy is associated with very low local-regional recurrence (LRR) rates for early-stage HER2+ breast cancer. One recent prospective study of T1-2N0 HER2+ breast cancer patients treated with lumpectomy and adjuvant paclitaxel+trastuzumab followed by whole breast radiation (RT) demonstrated 7-year LRR-free survival of 99% raising the question of whether local therapy de-escalation by RT omission is possible. To evaluate existing data on radiation omission, we used the National Cancer Database (NCDB) to test the hypothesis that RT omission results in equivalent overall survival (OS) in stage 1 (T1N0) HER2+ breast cancer.Materials/Methods: We identified patients with stage I (T1N0) HER2+ breast cancer treated with lumpectomy, adjuvant chemotherapy and anti-HER2 therapy from 2013 (the first year anti-HER2 therapy receipt was reliably collected) to 2015. We excluded patients that received neoadjuvant systemic therapy. We then stratified the cohort by receipt of adjuvant RT. The primary endpoint was OS as LRR is not captured by the NCDB. OS was analyzed by the Kaplan-Meier method (RT and RT omission groups compared by the log-rank test) and multivariate cox regression including variables with p&lt;0.20 on univariate analysis (hazard ratios [HR], and 95% confidence intervals [CI] are reported). Propensity score matched (PSM) analysis with patients matched on age (≥70 vs. &lt;70), comorbidities (≥1 vs. 0), grade (3 vs. 1-2), tumor size (&gt;1 cm vs. ≤1 cm), ER/PR status (ER-/PR- vs. ER+ and/or PR+), facility type (academic vs. non-academic), and income (&lt;$46,000/yr vs. ≥46,000/yr) was performed as an independent test of the Cox regression analysis.Results: We identified 6,897 patients that met the study criteria (6,388 RT; 509 no RT). Patients that did not receive RT tended to be older (mean age 64.0 years v. 59.2 years, p&lt;0.0001), have ≥1 comorbidity (21.4% vs. 14.8%, p&lt;0.0001), and live in lower income areas (60.1% vs. 52%, p=0.0004). Median follow-up was 29.4 months (IQR=19.5-39.9 months) with 155 deaths (95 RT; 60 RT omission). The 2-year OS was significantly worse for patients with RT omission (89.0% vs. 99.2%, p&lt;0.0001). Factors associated with OS on univariate analysis included RT omission (p&lt;0.0001), age≥70 (p&lt;0.0001), ≥1 comorbidity (p=0.0002), tumor size&gt;1cm (p=0.14), grade 3 tumors (p=0.14), academic facility (p=0.16) and lower income (p=0.02) but not ER-/PR- status (HR=1.01, p=0.95), distance to treatment facility (p=0.42) or tumor laterality (p=0.66). On multivariate analysis, RT omission (HR=7.55, 95% CI 5.36-10.63, p&lt;0.0001), age≥70 (HR=2.30, 95% CI 1.63-3.23, p&lt;0.0001), and ≥1 comorbidity (HR=1.45, 95% CI 1.00-2.09, p=0.05) remained independently associated with higher risk of death. The PSM cohort consisted of 509 pairs of patients with 73 deaths (13 RT; 60 RT omission) and median follow-up 26.4 months (IQR, 16.5-37.3 months). RT omission remained associated with a 5.42-fold (95% CI 3.02-9.73, p&lt;0.0001) increased risk of death in the PSM cohort.Conclusion: This study demonstrates that RT omission is independently associated with an increased risk of death in patients with stage I, HER2+, node-negative breast cancer treated with lumpectomy, adjuvant chemotherapy and anti-HER2 therapy. Patients that did not receive RT tended to be older, have more comorbidities and live in lower income areas. While other selection biases that influence RT omission likely persist, these data should give caution to RT omission in stage I, node-negative HER2+ breast cancer.

Citation Format: Jose G Bazan, Sachin Jhawar, Daniel Stover, Ko Un Park, Sasha Beyer, Erin Healy, Julia R White. De-escalation of radiation therapy in patients with stage I, node-negative, HER2-positive breast cancer: Patterns of care and survival outcomes using the national cancer database [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS15-04.

Abstract SS2-05: Emerging from COVID-19 pandemic: Provider perspective on use of neoadjuvant endocrine therapy (NET) in early stage hormone receptor positive breast cancer

IntroductionDuring the coronavirus 2019 (COVID-19) pandemic in USA, NET use has been recommended to allow safe deferral of surgical treatment in early stage, estrogen receptor positive breast cancer (ER+BC). In such circumstances, after NET use there is limited guidance on locoregional treatment, especially with management of the axilla. We aimed to evaluate patterns of care in early stage ER+BC during the first several months of the COVID-19 pandemic.MethodA cross-sectional, 30-item survey was developed using a standardized survey development framework. The survey was administered May 8 - June 12, 2020 to a convenience sample of medical oncologists (MO), radiation oncologists (RO), and surgeons (SO) - breast committee members of two national cooperative groups (Alliance and SWOG) with additional participation through chain referrals. Providers were presented with general questions on NET use before and during the pandemic. They were asked their propensity for omitting axillary lymph node dissection (ALND) after NET if 1 micrometastatic node is found on sentinel lymph node biopsy, based on duration of NET.Results114 providers from 29 US states completed the survey - 42 (37%) MO, 14 (12%) RO, and 58 (51%) SO, the majority (N=73/96, 76%) with practices dedicated ≥ 75% to BC, at NCI designated comprehensive cancer centers 52% (N=48/94) and in large cities (N=49/94, 52%). Prior to COVID-19, most rarely (N=49/107, 46%) or sometimes (N=36, 33%) used NET for early stage ER+BC. Nearly half were willing to delay surgery up to 2 months (46%) and 3 months (21%) without use of NET (Table 1, †p&lt;0.05). Most providers would perform a genomic assay on the biopsy specimen on all or select patients prior to NET initiation, more frequently by MO compared to RO and SO (90% vs. 75% and 60%, p&lt;0.05). The most preferred regimen was tamoxifen (without ovarian suppression) for premenopausal patients and aromatase inhibitor for postmenopausal patients. Most planned to use NET for as little time as possible until surgery could proceed. When stratified by specialty, more MO stated they would vary the duration of therapy based on patient’s risk of cancer progression. Most providers recommended omitting ALND after 1, 2, or 3 months of NET (1 month N=56/93, 60%; 2 months N=54/92, 59%; 3 months N=48/90, 53%). With longer duration of therapy, the propensity for omitting ALND decreased (definitely omit after 6 months N=25/91, 27%; probably omit after 6 months N=38/91, 42%; definitely omit after 1 year N=26/92, 28%; probably omit after 1 year N=29/92, 32%). Omitting ALND was not associated with provider’s years in practice, percent of practice dedicated to BC, practice type or setting, participation in multidisciplinary tumor board, or number of COVID-19 cases in the provider’s practicing state.ConclusionMost providers changed their management of early stage ER+BC during the COVID-19 pandemic by utilizing NET until surgery could proceed. As the duration of NET extended, more providers favored ALND in low volume axillary metastatic disease in early stage ER+BC. Additional data to inform the care on post-NET locoregional management is needed.

Table 1. Management of early stage, node negative, ER+BC during COVID-19 pandemicTotal (N, %)Med OncRad OncSurgeonHow long are you willing to delay surgery (without use of endocrine therapy)?Up to 1 month25 (23%)10 (24%)015 (26%)Up to 2 months51 (46%)17 (40%)7 (64%)27 (47%)Up to 3 months23 (21%)9 (21%)2 (18%)12 (21%)Up to 4 months3 (3%)2 (5%)1 (9%)0Up to 6 months8 (7%)4 (10%)1 (9%)3 (5%)Have you changed your practice during the current pandemic?Yes - institution mandated change to delay surgery8 (25%)4 (36%)04 (29%)Yes - based on multidisciplinary team discussion (no explicit institutional mandate to delay cancer surgery)21 (66%)6 (55%)7 (100%)8 (57%)No - was not allowed by institution to change0000No - was not necessary3 (9%)1 (9%)02 (14%)If using endocrine therapy before surgery, which regimen are you using?†Tamoxifen for all patients0000Tamoxifen for premenopausal patients; aromatase inhibitor for postmenopausal patients77 (81%)26 (63%)051 (94%)Ovarian suppression with aromatase inhibitor for premenopausal patients; aromatase inhibitor for postmenopausal patients18 (19%)15 (37%)03 (6%)How are you staging the axilla prior to starting endocrine therapy?Exam only28 (26%)8 (19%)2 (17%)18 (33%)Exam + US77 (71%)30 (71%)10 (83%)37 (67%)Exam + US + cross sectional image (CT scan)4 (4%)4 (10%)0 (0%)0 (0%)SLNB0000If using endocrine therapy first (before surgery), are you†Sending genomic assay on biopsy specimen on all patients28 (26%)18 (44%)1 (8%)9 (16%)Sending genomic assay on biopsy specimen on only select patients (ie. high grade, size on imaging/exam, high Ki-67)51 (48%)19 (46%)8 (67%)24 (44%)Not sending genomic assay. Using PEPI score instead.4 (4%)1 (2%)1 (8%)2 (4%)Not sending genomic assay. Using Magee Equations for Estimating Oncotype DX Recurrence Score instead.2 (2%)002 (4%)None of above21 (20%)3 (7%)2 (17%)18 (33%)If using endocrine therapy first, what duration do you plan to use it for the average patient?†Minimum 1 year for all patients0000Minimum 6 months for all patients7 (6%)4 (10%)0 (0%)3 (5%)Minimum 3 months for all patients19 (18%)7 (17%)1 (8%)11 (20%)As short as possible (less than 3 months), until it is safe to proceed with surgery in light of COVID-19 situation57 (53%)14 (34%)9 (75%)34 (62%)Duration of therapy depends on patient''s risk of cancer progression (ie. tumor grade, percent hormone positivity)25 (23%)16 (39%)2 (17%)7 (13%)If using endocrine therapy before surgery, do you plan to re-image the breast prior to surgery?†Yes, re-image all patients27 (25%)14 (34%)1 (8%)12 (22%)No8 (7%)0 (0%)2 (17%)6 (11%)Case by case basis72 (67%)27 (66%)9 (75%)36 (67%)

Citation Format: Ko Un Park, Megan E Gregory, Maryam B Lustberg, Jose G Bazan, Chengli Shen, Shoshana M Rosenberg, Victoria S Blinder, Priyanka Sharma, Lajos Pusztai, Ann H Partridge, Alastair Thompson. Emerging from COVID-19 pandemic: Provider perspective on use of neoadjuvant endocrine therapy (NET) in early stage hormone receptor positive breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SS2-05.

Association of Pre- and Posttreatment Neutrophil-Lymphocyte Ratio With Recurrence and Mortality in Locally Advanced Non-Small Cell Lung Cancer

Objectives

Neutrophil–lymphocyte ratio (NLR) has been associated with mortality in non-small cell lung cancer (NSCLC), but its association with recurrence in locally advanced NSCLC (LA-NSCLC), specifically, is less established. We hypothesized pre- and posttreatment NLR would be associated with recurrence and mortality.

Methods

We studied the association of pretreatment NLR (pre-NLR) and posttreatment NLR at 1 (post-NLR₁) and 3 months (post-NLR₃) with outcomes in patients with LA-NSCLC treated with chemoradiation. Pre-NLR was dichotomized by 5, an a priori cutoff previously shown to be prognostic in LA-NSCLC. Post-NLR₁ and post-NLR₃ were dichotomized by their medians.

Results

We identified 135 patients treated with chemoradiation for LA-NSCLC between 2007 and 2016. Median follow-up for living patients was 61.1 months. On multivariable analysis, pre-NLR ≥ 5 was associated with worse overall survival (HR = 1.82; 95% CI 1.15 – 2.88; p = 0.011), but not with any recurrence, locoregional recurrence, or distant recurrence. Post-NLR₁ ≥ 6.3 was not associated with recurrence or survival. Post-NLR₃ ≥ 6.6 was associated with worse overall survival (HR = 3.27; 95% CI 2.01– 5.31; p < 0.001), any recurrence (HR = 2.50; 95% CI 1.53 – 4.08; p < 0.001), locoregional recurrence (HR = 2.50; 95% CI 1.40 – 4.46; p = 0.002), and distant recurrence (HR = 2.53; 95% CI 1.49 – 4.30; p < 0.001).

Conclusion

Pretreatment NLR is associated with worse overall survival and posttreatment NLR is associated with worse survival and recurrence. These findings should be validated independently and prospectively studied.

Dosimetric parameters associated with radiation-induced esophagitis in breast cancer patients undergoing regional nodal irradiation

BACKGROUND/PURPOSE

Rates of acute esophagitis in breast cancer patients undergoing regional nodal irradiation (RNI) are under-reported. We set to identify esophageal dose-volume constraints associated with grade 2 esophagitis (G2E). We hypothesized that the G2E rate was higher with intensity modulated radiation therapy (IMRT) vs. 3D conformal radiation therapy (3DCRT).

MATERIALS/METHODS

We identified patients that received RNI (50 Gy/25 fractions) from 1/2013 to 6/2019. We retrospectively contoured the esophagus in a consistent manner and recorded esophageal mean dose, max dose, and V10-V50. Our primary endpoint was the G2E rate. Receiver operating characteristics curves analysis (e.g., Youden's J statistic) were used to determine the cutpoints for the dosimetric parameters which were then tested in logistic regression models.

RESULTS

We identified 531 patients (50% left-sided; 41% IMRT; 16.2% G2E). G2E was significantly higher in IMRT vs. 3DCRT patients (23.6% vs. 10.9%, p < 0.0001). All esophageal dosimetric parameters were significantly associated with G2E after adjusting for age and laterality. The cutpoints for esophageal mean dose, V10 and V20 were 11 Gy, 30%, and 15%, respectively. The associations between the dichotomized dose-volume parameters and G2E were OR = 3.82 (95% CI 2.28-6.40, p < 0.0001) for esophageal mean dose, OR = 5.37 (95% CI 3.01-9.58, p < 0.0001) for esophageal V10, and OR = 3.23 (95% CI 1.93-5.41, p < 0.0001) for esophageal V20.

CONCLUSION

In patients receiving RNI with modern techniques, we found that G2E occurs in >15%, and more frequently with IMRT. These data strongly support the routine contouring of the esophagus in RNI planning, and our constraints should be incorporated in future prospective protocols of RNI.

Clinical Effectiveness of an Adaptive Treatment Planning Algorithm for Intensity Modulated Radiation Therapy Versus 3D Conformal Radiation Therapy for Node-Positive Breast Cancer Patients Undergoing Regional Nodal Irradiation/Postmastectomy Radiation Therapy

PURPOSE

Clinical trials support adjuvant regional nodal irradiation (RNI) after breast-conserving surgery or mastectomy for patients with lymph node-positive breast cancer. Advanced treatment planning techniques (eg, intensity modulated radiation therapy [IMRT]) can reduce dose to organs at risk (OARs) in this situation. However, uncertainty persists about when IMRT is clinically indicated (vs 3-dimensional conformal radiation therapy [3DCRT]) for RNI. We hypothesized that an adaptive treatment planning algorithm (TPA) for IMRT adoption would allow OAR constraints for RNI to be met when 3DCRT could not without significantly changing toxicity and locoregional recurrence (LRR) patterns.

METHODS AND MATERIALS

Since 2013, all RNI patients also underwent an adaptive TPA that began with 3DCRT and then changed to IMRT when OAR constraints (mean heart dose ≤500 cGy; ipsilateral lung V20 ≤35%) could not be met. Patients received 2 Gy/d to the prospectively contoured target volumes (including internal mammary nodes). We retrospectively evaluated the dosimetry and clinical outcomes of the treatment groups (IMRT vs 3DCRT). The primary endpoint was the cumulative incidence of LRR as the site of first recurrence, and we specifically address patterns of failure based on dose to the posterior supraclavicular nodal region (SCL-post).

RESULTS

Two hundred forty patients (60% stage III; mean 4.0 + nodes) underwent an adaptive-TPA for RNI after mastectomy (74%) or breast-conserving surgery (26%), resulting in 168 patients treated with 3DCRT and 72 patients treated with IMRT. There were 7 LRRs (2 IMRT, 5 3DCRT) resulting in 4-year LRR of 2.8% for IMRT versus 1.8% for 3DCRT (P = .99). Three patients (2 IMRT, 1 3DCRT) had SCL nodal failures (1 in the SCL-post).

CONCLUSIONS

An adaptive TPA for use of IMRT when 3DCRT does not meet critical OAR constraints resulted in rare high-grade toxicity and no difference in failure patterns between patients treated with IMRT and 3DCRT. These data should provide reassurance that IMRT maintains the therapeutic ratio by preserving cancer control outcomes without excess toxicity when 3DCRT fails to meet OAR constraints.