Trends in Use of Hypofractionated Whole Breast Radiation in Breast Cancer: An Analysis of the National Cancer Database

Early-Stage Breast Cancer: A Critical Review of Current and Emerging Practice

Breast-conserving surgery followed by adjuvant radiation to reduce the risk of ipsilateral breast tumor recurrence is the mainstay of treatment for early-stage breast cancer (ESBC). However, improved understanding of the heterogeneity of the clinical and molecular characteristics of ESBC has led to greater efforts to personalize approaches to treatment. Furthermore, advances in the understanding of the radiobiology of breast cancer have led to several practice-changing trials on the effectiveness and tolerability of moderate and ultrahypofractionated radiation. Here, we review the recent evidence and ongoing research in the radiotherapeutic management of ESBC, including the use of boost for high-risk disease and opportunities for accelerated fractionation, partial breast irradiation, and radiation omission for low-risk disease. We also discuss how molecular profiling can inform decision-making and new opportunities for primary radiation therapy and reirradiation.

Increase in Hypofractionated Radiation Therapy Among Patients with Invasive Breast Cancer or Ductal Carcinoma In Situ: Who is Left Behind?

PURPOSE

We aimed to update the trend of hypofractionated whole-breast irradiation (HF-WBI) use over time in the US and examine factors associated with lack of HF-WBI adoption for patients with early-stage invasive breast cancer (IBC) or ductal carcinoma in situ (DCIS) undergoing a lumpectomy.

METHODS AND MATERIALS

Among patients who underwent a lumpectomy, we identified 928,034 patients with early-stage IBC and 330,964 patients with DCIS in the 2004 to 2020 National Cancer Database. We defined HF-WBI as 2.5-3.33 Gy/fraction to the breast and conventionally fractionated WBI as 1.8-2.0 Gy/fraction. We evaluated the trend of HF-WBI utilization using a generalized linear model with the log link and binomial distribution. Factors associated with HF-WBI utilization were assessed using multivariable logistic regression in patients diagnosed between 2018 and 2020.

RESULTS

Among patients with IBC, HF-WBI use has significantly increased from 0.7% in 2004 to 63.9% in 2020. Similarly, HF-WBI usage among patients with DCIS has also increased significantly from 0.4% in 2004 to 56.6% in 2020. Black patients with IBC were less likely than White patients to receive HF-WBI (adjusted odds ratio [AOR] 0.81; 95% CI, 0.77-0.85). Community cancer programs were less likely to administer HF-WBI to patients with IBC (AOR, 0.80; 95% CI, 0.77-0.84) and to those with DCIS (AOR, 0.87; 95% CI, 0.79-0.96) than academic/research programs. Younger age, positive nodes, larger tumor size, low volume programs, and facility location were also associated with lack of HF-WBI adoption in both patient cohorts.

CONCLUSIONS

HF-WBI utilization among postlumpectomy patients has significantly increased from 2004 to 2020 and can finally be considered standard of care in the US. We found substantial disparities in adoption within patient and facility subgroups. Reducing disparities in HF-WBI adoption has the potential to further alleviate health care costs while improving patients' quality of life.

Expenditures and Use of Hypofractionated Radiation Therapy Treating Breast Cancer Among Medicare Advantage Enrollees, 2009 to 2017

Purpose

Technology advances in cancer care have paralleled rapidly increasing expenditures in radiation therapy. The use and costs of shorter cancer radiation therapy offer potential utility in clinical practice. We evaluate use and expenditures of Medicare Advantage (MA) beneficiaries receiving hypofractionated whole breast irradiation (HF-WBI) compared with conventionally fractionated whole breast irradiation (CF-WBI) in the United States and examine the relationship of patient characteristics with HF-WBI use.

Methods and Materials

We performed a retrospective analysis of radiation therapy in MA beneficiaries using private employer-sponsored insurance claims for a pooled cross-sectional evaluation from 2009 to 2017. The study population included female MA beneficiaries with early-stage breast cancer treated with lumpectomy and whole breast irradiation.

Results

A total of 9957 women received HF-WBI, and 18,920 received CF-WBI. Older age, greater distance from home to treatment facility, and a higher proportion of college graduates in the community of residence were associated with increased HF-WBI use. Mean insurer-paid radiation therapy expenditures were significantly lower for HF-WBI versus CF-WBI (adjusted difference, $4113; 95% CI, $4030-$4,197). Mean patient out-of-pocket expenditure for HF-WBI was $426 less than that of CF-WBI. Across US states, geographic variation existed in the ratio of costs for HF-WBI relative to CF-WBI (range, 0.41-0.87).

Conclusions

HF-WBI use among MA beneficiaries with breast cancer has dramatically increased over time, surpassing CF-HBI as the dominant form of radiation therapy. HF-WBI clinical adoption has outpaced any continual cost decrease, despite wide variation across US states for this shorter radiation therapy treatment. As MA enrollment continues to expand, identifying the drivers of HF-WBI use and the sources of variation in costs of HF-WBI will help direct the quality of cancer care delivered to Medicare beneficiaries.

Caught Between a Radiation Oncology Case Rate (ROCR) and a Hard Place: Improving Proposed Radiation Oncology Alternative Payment Models

PURPOSE

The Radiation Oncology Case Rate (ROCR) aims to shift radiation reimbursement from fee-for-service (FFS) to bundled payments, which would decouple fractionation from reimbursement in the United States. This study compares historical reimbursement rates from 3 large centers and a national Medicare sample with proposed base rates from ROCR. It also tests the impact of methodological inclusion of treatment and disease characteristics to determine if any variables are associated with greater rate differences that may lead to inequitable reimbursement.

METHODS AND MATERIALS

Using Mayo Clinic electronic medical record data from 2017 to 2020 and part B claims from the Medicare 5% research identifiable files, episodic 90-day historical reimbursement rates for 15 cancer types were calculated per the ROCR payment methodology. Mayo Clinic reimbursement rates were stratified by disease and treatment characteristics and multiple linear regression was performed to assess the association of these variables on historical episode reimbursement rates.

RESULTS

From Mayo Clinic, 3498 patient episodes were included and 480,526 from the research identifiable files. From both data sets, 25% of brain metastases and 13% of bone metastases episodes included ≥2 treatment courses with an average of 51 days between courses. Accounting for all 15 cancer types, ROCR base rates resulted in an average -2.4% and -2.9% reduction in rates for Mayo Clinic and the research identifiable files respectively compared with historical reimbursement. On multivariate analysis of Mayo Clinic data, treatment intent (curative vs palliative) was associated with higher historical reimbursement (+$477 to +$7417; P ≤.05) for 12 out of 12 applicable cancer types. Stage (III-IV vs I-II) was associated with higher historical reimbursement (+$1169 to +$3917; P ≤ .05) for 8 out of 12 applicable cancer types.

CONCLUSIONS

Our data suggest ROCR base rates introduce an average ≤3% reimbursement rate decrease compared with historical FFS reimbursement per cancer type, which could produce the Medicare savings required for congressional approval of ROCR. Estimating comparisons with future FFS reimbursement would require consideration of additional factors such as the increased utilization of hypofractionation, proposed FFS rate cuts, and inflationary updates. A distinct rate and shortened episode duration (≤30 days) should be considered for palliative episodes. Applying a base rate modifier per cancer stage may mitigate disproportionate reductions in reimbursement for facilities with a higher volume of curative advanced-stage patients such as freestanding centers in rural settings.

Quantification of the environmental impact of radiotherapy and associated secondary human health effects: a multi-institutional retrospective analysis and simulation

BACKGROUND

The health-care industry is a substantial contributor to global greenhouse gas emissions, yet the specific environmental impact of radiotherapy, a cornerstone of cancer treatment, remains under-explored. We aimed to quantify the emissions associated with the delivery of radiotherapy in the USA and propose a framework for reducing the environmental impact of oncology care.

METHODS

In this multi-institutional retrospective analysis and simulation study, we conducted a lifecycle assessment of external beam radiotherapy (EBRT) for ten anatomical disease sites, adhering to the International Organization for Standardization's standards ISO 14040 and ISO 14044. We analysed retrospective data from Jan 1, 2017, to Oct 1, 2023, encompassing patient and staff travel, medical supplies, and equipment and building energy use associated with the use of EBRT at four academic institutions in the USA. The primary objective was to measure the environmental impacts across ten categories: greenhouse gases (expressed as kg of carbon dioxide equivalents [CO2e]), ozone depletion, smog formation, acidification, eutrophication, carcinogenic and non-carcinogenic potential, respiratory effects, fossil fuel depletion, and ecotoxicity. Human health effects secondary to these environmental impacts were also estimated as disability-adjusted life years. We also assessed the potential benefits of hypofractionated regimens for breast and genitourinary (ie, prostate and bladder) cancers on US greenhouse gas emissions using an analytic model based on the 2014 US National Cancer Database for fractionation patterns and patient commute distances.

FINDINGS

We estimated that the mean greenhouse gas emissions associated with a standard 25-fraction EBRT course were 4310 kg CO2e (SD 2910), which corresponded to 0·0035 disability-adjusted life years per treatment course. Transit and building energy usage accounted for 25·73% (1110 kg CO2e) and 73·95% of (3190 kg CO2e) of total greenhouse gas emissions, respectively, whereas supplies contributed only 0·32% (14 kg CO2e). Across the other environmental impact categories, most of the environmental impact also stemmed from patient transit and energy use within facilities, with little environmental impact contributed by supplies used. Hypofractionated treatment simulations suggested a substantial reduction in greenhouse gas emissions-by up to 42% for breast and 77% for genitourinary cancer-and environmental impacts more broadly.

INTERPRETATION

This comprehensive lifecycle assessment of EBRT delineates the environmental and secondary health impacts of radiotherapy, and underscores the urgent need for sustainable practices in oncology. The findings serve as a reference for future decarbonisation efforts in cancer care and show the potential environmental benefits of modifying treatment protocols (when clinical equipoise exists). They also highlight strategic opportunities to mitigate the ecological footprint in an era of escalating climate change and increasing cancer prevalence.

FUNDING

Mount Zion Health Fund.

Geographic and Physician-Level Variation in the Use of Hypofractionated Radiation Therapy for Breast Cancer in the U.S.: A Cross-Classified Multilevel Analysis

Purpose

We aimed to assess geographic and physician-level variation for hypofractionated whole-breast irradiation (HF-WBI) use for early-stage breast cancer patients in the United States. We further evaluated the association between HF-WBI use and demographic factors after accounting for these variations.

Methods and Materials

We performed a retrospective study of early-stage breast cancer patients using private employer-sponsored insurance claims from 2008 to 2017. Patients were clustered according to geographic level and by radiation oncologist. Bayesian cross-classified multilevel logistic models were used to examine the geographic heterogeneity and variation of radiation oncologists simultaneously. Intracluster correlation coefficient (ICC) and median odds ratios (MOR) were calculated to quantify the variation at different levels. We also used the cross-classified model to identify patient demographic factors associated with receiving HF-WBI.

Results

The study included 79,747 women (74.0%) who received conventionally fractionated whole-breast irradiation (CF-WBI) and 27,999 women (26.0%) who underwent HF-WBI. HF-WBI adoption increased significantly across time (2008-2017). The variation in HF-WBI utilization was attributed mostly to physician-level variability (MOR = 2.59). The variability of HF-WBI utilization across core-based statistical areas (CBSAs) (MOR = 1.55) was found to be the strongest among all geographic classifications. After accounting for variability in both CBSAs and radiation oncologists, age, receiving chemotherapy, and several community-level factors, including distance from home to facility, community education level, and racial composition, were found to be associated with HF-WBI utilization.

Conclusion

This study demonstrated geographic and physician-level heterogeneity in the use of HF-WBI among early-stage breast cancer patients. HF-WBI utilization was also found to be associated with patient and community-level characteristics. Given observed physician-level variability, intervention through continuing medical education could help doctors to better understand the advantages of HF-WBI and promote the adoption of HF-WBI in the U.S. Influence of physician-level characteristics on HF-WBI utilization merits further study.

Evidence-based clinical recommendations for hypofractionated radiotherapy: exploring efficacy and safety - Part 2. Lung (non-small cell lung cancer)

Several recent studies have investigated the use of hypofractionated radiotherapy (HFRT) for various cancers. However, HFRT for non-small cell lung cancer (NSCLC) with or without concurrent chemotherapy is not yet widely used because of concerns about serious side effects and the lack of evidence for improved treatment results. Investigations of HFRT with concurrent chemotherapy in NSCLC have usually been performed in single-arm studies and with a small number of patients, so there are not yet sufficient data. Therefore, the Korean Society for Radiation Oncology Practice Guidelines Committee planned this review article to summarize the evidence on HFRT so far and provide it to radiation oncology clinicians. In summary, HFRT has demonstrated promising results, and the reviewed data support its feasibility and comparable efficacy for the treatment of locally advanced NSCLC. The incidence and severity of esophageal toxicity have been identified as major concerns, particularly when treating large fraction sizes. Strategies, such as esophagus-sparing techniques, image guidance, and dose constraints, may help mitigate this problem and improve treatment tolerability. Continued research and clinical trials are essential to refine treatment strategies, identify optimal patient selection criteria, and enhance therapeutic outcomes.

Outcomes of whole breast radiation therapy in Asian breast cancer patients with prior cosmetic implants

BACKGROUND

As breast augmentation has become more popular, an increasing number of women with augmented breasts require treatment for breast cancer. This study aimed to assess the outcomes of postoperative whole breast radiation therapy (WB-RT) in Asian patients with breast cancer who underwent prior cosmetic breast implantation.

METHODS

We retrospectively reviewed the medical records of 61 patients with breast cancer who had prior cosmetic breast implants (prior-CBI) and underwent breast-conserving surgery (BCS) and WB-RT between 2015 and 2020. The median implant volume was 238.8 cc, with a median interval of 84.7 months between the prior-CBI and BCS. WB-RT was administered with either conventional fractionation (CF-RT) at 50 Gy in 25 fractions (N = 36) or hypofractionation (HF-RT) at 42.6 Gy in 16 fractions (N = 25). The incidences of implant-related complications (IRC) and their contributing factors were analyzed.

RESULTS

After a median follow-up of 43.5 months, the 3-year cumulative incidences of IRC and implant loss were 17.2% and 4.9%, respectively. Among the four (6.6%) patients who opted for implant removal after RT, three were potentially related to RT-related capsular contracture. There was no difference in the 3-year cumulative IRC rates following CF-RT and HF-RT (12.2% and 26.7%, respectively; p = 0.120). The risk factors for IRC included a larger implant size (> 260 cc) and a higher ratio of breast tissue to implant volume.

CONCLUSIONS

This study demonstrated a favorable safety profile of WB-RT for treatment of breast cancer in Asian women with prior-CBI. The integration of HF-RT following BCS was thought to be a feasible approach.

Use of Radiation Therapy for the Treatment of Breast Cancer in 2019 Versus 2020

Purpose

The COVID-19 pandemic disrupted medical care. Little is known about how radiation therapy (RT) ordering behavior changed during the pandemic. This study examined (1) whether there was a change in the rate at which orders for lumpectomy were followed by orders for RT and (2) whether there was a change in the percentage of RT orders for hypofractionated (HF) RT rather than conventionally fractionated (CF) RT.

Methods and Materials

Prior authorization order data from 2019 and 2020, pertaining to patients with commercial and Medicare Advantage health plans, were reviewed to determine whether patients had an order for RT in the 90 days after lumpectomy and if it was for CF or HF RT. Univariate analyses were conducted using χ2 tests, and adjusted analyses were conducted using multivariate logistic regression, controlling for patient age, urbanicity, local median income, region, if the lumpectomy facility was academic, and if the lumpectomy facility was a hospital.

Results

In 2019, 47.7% of included lumpectomy orders (2200/4610) were followed by an RT order within 90 days, in contrast to 45.6% (1944/4263) in 2020 (P = .048). Of the RT orders meeting this study's definition of CF or HF, 75.3% of orders placed in 2019 (1387/1843) and 79.0% of orders placed in 2020 (1261/1597) were for HF (P = .011). Adjusted analysis found patients receiving a lumpectomy order in the first quarter of 2020 had significantly reduced odds (odds ratio, 0.84; 95% CI, 0.71-0.99) of receiving an order for RT after lumpectomy, relative to those with orders placed in the first quarter of 2019. Adjusted analysis likewise found significant evidence of increased use of HF RT during the pandemic.

Conclusions

In the population examined, physicians were less likely to order RT after lumpectomy in 2020 than in 2019, and if they did, were more likely to order HF RT.

Feasibility of Intraoperative Radiotherapy Tumor Bed Boost in Patients with Breast Cancer after Neoadjuvant Chemotherapy

PURPOSE

This study aimed to assess the feasibility and safety of administering intraoperative radiotherapy (IORT) as a boost during breast-conserving surgery (BCS) following neoadjuvant chemotherapy for patients at high risk of breast cancer recurrence.

MATERIALS AND METHODS

Patients who underwent neoadjuvant chemotherapy received a single 20-Gy dose of IORT during BCS, followed by external beam radiotherapy 4-6 weeks after surgery.

RESULTS

The median follow-up duration was 31.0 months (range, 18.0-59.0 months). Initial tumor sizes had a median of 2.6 cm (range: 0.8-5.3 cm), reducing to 0.3 cm (range: 0-4.0 cm) after neoadjuvant chemotherapy. The most common neoadjuvant chemotherapy regimen was doxorubicin and cyclophosphamide, followed by paclitaxel (n=42, 73.7%). Among 57 patients who received neoadjuvant chemotherapy before BCS and IORT, 2 patients (3.5%) required secondary surgery to achieve negative resection margins due to initially positive margins. Regional lymph node irradiation was performed in 37 (64.9%) patients. There was no grade 3 or higher adverse events, with 4 patients (7.0%) experiencing grade 2 acute radiation dermatitis and 3 (5.3%) having less than grade 2 breast edema. Binary correlation analysis did not reveal statistically significant associations between applicator size or radiation therapy modality and the risk of treatment-related toxicity. Furthermore, chi-square analysis showed that the grade of treatment-related toxicity was not associated with the fractionated regimen (p=0.375).

CONCLUSION

Most patients successfully received IORT as a tumor bed boost after neoadjuvant chemotherapy. Thus, IORT may be a safe and feasible option for patients with advanced-stage breast cancer receiving neoadjuvant chemotherapy.

Large institutional experience of early outcomes and dosimetric findings with postoperative stereotactic partial breast irradiation in breast cancer

PURPOSE

To analyze the dosimetric and toxicity outcomes of patients treated with postoperative stereotactic partial breast irradiation (S-PBI).

METHODS

We identified 799 women who underwent S-PBI at our institution between January 2016 and December 2022. The most commonly used dose-fraction and technique were 30 Gy in 5 fractions (91.7 %) and a robotic stereotactic radiation system with real-time tracking (83.7 %). The primary endpoints were dosimetric parameters and radiation-related toxicities. For comparison, a control group undergoing ultra-hypofractionated whole breast irradiation (UF-WBI, n = 468) at the same institution was selected.

RESULTS

A total of 815 breasts from 799 patients, with a median planning target volume (PTV) volume of 89.6 cm3, were treated with S-PBI. Treatment plans showed that the mean and maximum doses received by the PTV were 96.2 % and 104.8 % of the prescription dose, respectively. The volume of the ipsilateral breast that received 50 % of the prescription dose was 32.3 ± 8.9 %. The mean doses for the ipsilateral lung and heart were 2.5 ± 0.9 Gy and 0.65 ± 0.39 Gy, respectively. Acute toxicity occurred in 175 patients (21.5 %), predominantly of grade 1. Overall rate of late toxicity was 4 % with a median follow-up of 31.6 months. Compared to the UF-WBI group, the S-PBI group had comparably low acute toxicity (21.5 % vs. 25.2 %, p = 0.12) but significantly lower dosimetric parameters for all organs-at-risks (all p < 0.05).

CONCLUSION

In this large cohort, S-PBI demonstrated favorable dosimetric and toxicity profiles. Considering the reduced radiation exposure to surrounding tissues, external beam PBI with advanced techniques should at least be considered over traditional WBI-based approaches for PBI candidates.

Dosimetry and Toxicity Outcomes in Patients Treated with Hypofractionated Regional Nodal Irradiation for Breast Cancer: What is the Best Dose-Volume Limit to Minimize Risks of Radiation Pneumonitis?

PURPOSE

Although published data have supported the use of hypofractionated regional nodal irradiation (HF-RNI) for breast cancer, limited dosimetric data exist to evaluate predictors of lung toxicity. The ongoing RT CHARM trial limits the percentage of ipsilateral lung volume that receives ≥18 Gy to 35 to 40%. We assessed dosimetry, toxicity, and disease outcomes in patients with breast cancer treated with HF-RNI with a particular focus on pneumonitis.

METHODS AND MATERIALS

We retrospectively reviewed all patients with breast cancer treated with HF-RNI (40-43 Gy in 15-16 fractions) after either lumpectomy or mastectomy at The University of Pittsburgh Medical Center from September 2018 to December 2021 to collect dosimetric and outcomes data. All post-radiation therapy chest computed tomography (CT) scans were manually reviewed for evidence of acute (≤6 months postradiation) or chronic (>6 months postradiation) pneumonitis.

RESULTS

One-hundred-ninety-one patients qualified with a median follow-up of 20.3 months (range, 5.1-42.2). Acute grade 1 (G1) pneumonitis was observed in 6.8% of the overall cohort (13 of 191 patients) and 39.4% of the patients (13 of 33) who received a chest CT ≤6 months postradiation therapy. Only 1 patient developed acute G2 pneumonitis. Chronic G1 pneumonitis was observed in 29.8% of the overall cohort (57 of 191 patients) and 77% of patients (57 of 74 patients) who received a chest CT >6 months postradiation therapy. No patients developed acute G3+ or chronic G2+ pneumonitis.

CONCLUSIONS

Rates of symptomatic pneumonitis were low in this cohort of patients treated with HF-RNI, even with integration of HER2/neu-directed therapy, chemotherapy, hormone therapy, and internal mammary nodal irradiation. Lung V20Gy <26% appeared safe in this cohort to limit symptomatic pneumonitis, though this is not meant to represent the safe upper limit. Given the low event rate of symptomatic pneumonitis, data from larger cohorts will be needed to assess dosimetric predictors and the safe upper limit of lung dose.

Incorporating financial toxicity considerations into clinical trial design to facilitate patient-centered decision-making in oncology

PLAIN LANGUAGE SUMMARY

Financial toxicity is increasingly being recognized as an important and devastating consequence of cancer treatment that receives little attention when clinical trials are being designed. There is a significant need to obtain this important information in an era of increasingly expensive anticancer treatments. Patients who are informed of all implications of therapy-efficacy, side effects, cost, and broader financial impact-are able to select the best cancer treatment for themselves.

Development and Validation of a Normal Tissue Complication Probability Model for Lymphedema After Radiation Therapy in Breast Cancer

PURPOSE

To develop and test a multivariable normal tissue complication probability (NTCP) model predicting lymphedema in patients with breast cancer receiving radiation therapy.

METHODS AND MATERIALS

We retrospectively reviewed 1345 patients with breast cancer who received radiation therapy from 2 independent institutions. The patients were divided into a training cohort (institution A, n = 368, all treated with 3-dimensional conformal external beam radiation therapy [RT] with 2 Gy/fraction) and an external validation cohort (institution B, n = 977, treated either with 3-dimensional conformal external beam RT or with volumetric modulated RT and either with 1.8-2.0 Gy/fraction or with 2.67 Gy/fraction). Axillary-lateral thoracic vessel juncture (ALTJ) was delineated. The multivariable model was generated using dosimetric and clinical parameters. The performance of the model was comprehensively validated internally and externally.

RESULTS

During a median follow-up of 78.7 months for the entire cohort, 97 patients (7.2%) developed lymphedema. The multivariable model that took into account the number of lymph nodes dissected, as well as the volume of the ALTJ receiving a dose ≥35 Gy equivalent doses in 2-Gy fractions (ALTJ V35), showed good agreement between predicted and observed results for both internal and external validation (Hosmer-Lemeshow P value > .05). The area under the receiver operating characteristic curve (AUC) and negative log-likelihood values for the multivariable NTCP model were 0.89 and 0.19 in internal validation and 0.83 and 0.19 in external validation. In addition, the multivariable model performance was acceptable for hypofractionated regimens (AUC 0.70) and volumetric modulated arc therapy (AUC 0.69). The number of lymph nodes dissected and ALTJ V35 were found to be the most important factors influencing lymphedema after radiation therapy.

CONCLUSIONS

We first developed and validated the multivariable NTCP model for the lymphedema incidence in patients with breast cancer after radiation therapy. The multivariable NTCP model showed excellent performance and robustness in predicting lymphedema in both internal and completely independent external validations. The multivariable model for lymphedema prediction was robust and reliable for different treatment modalities and fractionation regimens.

Global research trends in radiotherapy for breast cancer: a systematic bibliometric analysis

PURPOSE

Breast cancer is the most common malignant tumor in women. Radiotherapy (RT) is an important adjunctive therapy for breast cancer, but the current international research trend of RT in breast cancer treatment and management is unclear. This bibliometric analysis was conducted to investigate the current trends and hot topics in this area.

MATERIALS AND METHODS

The Web of Science Core Collection (WoSCC; Clarivate) database was searched, VOSviewer 1.6.18 and CiteSpace 6.1.R2 software were employed for the quantitative and qualitative analysis.

RESULTS

12,268 publications were included in this bibliometric analysis. There was an increasing trend of publications and international collaborations in the topic. The United States and The University of Texas MD Anderson Cancer Center were the most productive countries and institutions, respectively. The analysis of journals showed researches focused on both basic and clinical medicine on breast cancer RT. Park Won published the most papers and Fisher B had the most co-citations. The most co-cited paper was published in the Lancet. Survival, risk, chemotherapy, mastectomy, and surgery were regarded as current research hotspots through the analysis of keywords.

CONCLUSION

Through quantitative and qualitative bibliometric analyses, this study provides insights into the research trends and potential research hotspots on breast cancer RT.

Journey to hypofractionation in radiotherapy for breast cancer: critical reviews for recent updates

Historical conventional fractionated radiation therapy (RT) for breast cancer consisted of 1.8-2.0 Gy per fraction with a total dose of 45-60 Gy over 5-7 weeks. Based on radiobiological characteristics, a low α/β is suspected of breast cancer resulting in sensitivity to higher dose per fraction (2.5-3.0 Gy). Over the past 10 years, multiple clinical trials support the application of shorter treatment regimen with hypofractionated RT (HypoRT). Recently, ultra-HypoRT with 5 fractions showed favorable outcomes. Although the safety and efficacy of HypoRT has been supported by high-quality randomized trials, there are still some worries and doubts around HypoRT from radiation oncologists. However, the radiation oncology community have now reached an important timepoint for adopting HypoRT during the COVID-19 pandemic. The aim of this review is to provide an overview of HypoRT in breast cancer based on prospective randomized trials and discuss the special consideration regarding HypoRT.

Treatment-related thoracic soft tissue sarcomas in US breast cancer survivors: a retrospective cohort study

BACKGROUND

Soft tissue sarcoma is a rare but serious side-effect of radiotherapy to treat breast cancer, and rates are increasing in the USA. We evaluated potential co-factors in two complimentary cohorts of US breast cancer survivors.

METHODS

In this retrospective cohort study, we sourced data from the Kaiser Permanente (KP) cohort and the Surveillance, Epidemiology, and End Results (SEER) 13 registries cohort, both in the USA. The KP cohort included 15 940 women diagnosed with breast cancer from Jan 1, 1990, to Dec 31, 2016, in KP Colorado, KP Northwest (which serves Oregon and Southwest Washington state), or KP Washington, with detailed treatment data and comorbidities (including hypertension and diabetes at or before breast cancer diagnosis) from electronic medical records. The SEER cohort included 457 300 women diagnosed with breast cancer from Jan 1, 1992, to Dec 31, 2016, within the 13 SEER registries across the USA, with initial treatment data (yes vs no or unknown). Eligibility criteria in both cohorts were female breast cancer survivors (stage I-III) aged 20-84 years at diagnosis who had breast cancer surgery, and had survived at least 1 year after breast cancer diagnosis. The outcome of interest was any second thoracic soft tissue sarcoma (angiosarcomas and other subtypes) that developed at least 1 year after breast cancer diagnosis. Risk factors for thoracic soft tissue sarcoma were assessed using multivariable Poisson regression models.

FINDINGS

In the KP cohort, median follow-up was 9·3 years (IQR 5·7-13·9) and 19 (0·1%) of 15 940 eligible, evaluable women developed a thoracic soft tissue sarcoma (11 angiosarcomas, eight other subtypes). Most (94·7%; 18 of 19) thoracic soft tissue sarcomas occurred in women treated with radiotherapy; thus, radiotherapy was associated with a significantly increased risk of developing a thoracic soft tissue sarcoma (relative risk [RR] 8·1 [95% CI 1·1-60·4]; p=0·0052), but there was no association with prescribed dose, fractionation, or boost. The RR of angiosarcoma after anthracyclines was 3·6 (95% CI 1·0-13·3; p=0·058). Alkylating agents were associated with an increased risk of developing other sarcomas (RR 7·7 [95% CI 1·2-150·8]; p=0·026). History of hypertension (RR 4·8 [95% CI 1·3-17·6]; p=0·017) and diabetes (5·3 [1·4-20·8]; p=0·036) were each associated with around a five-times increased risk of angiosarcoma. In the SEER cohort, 430 (0·1%) of 457 300 patients had subsequent thoracic soft tissue sarcomas (268 angiosarcomas and 162 other subtypes) after a median follow-up of 8·3 years (IQR 4·3-13·9). Most (77·9%; 335 of 430) cases occurred after radiotherapy; thus, radiotherapy was associated with a significantly increased risk of developing a thoracic soft tissue sarcoma (RR 3·0 [95% CI 2·4-3·8]; p<0·0001) and, for angiosarcomas, the RR for breast-conserving surgery plus radiotherapy versus mastectomy plus radiotherapy was 1·9 (1·1-3·3; p=0·012). By 10 years after radiotherapy, the cumulative incidence of thoracic soft tissue sarcoma was 0·21% (95% CI 0·12-0·34) in the KP cohort and 0·15% (95% CI 0·13-0·17) in SEER.

INTERPRETATION

Radiotherapy was the strongest risk factor for thoracic soft tissue sarcoma in both cohorts. This finding, along with the novel findings for diabetes and hypertension as potential risk factors for angiosarcomas, warrant further investigation as potential targets for prevention strategies and increased surveillance.

FUNDING

US National Cancer Institute and National Institutes of Health.

Moderately hypofractionated radiation therapy for breast cancer: A Brazilian cohort study

Background

Results from numerous clinical trials have led to a consensus that moderately hypofractionated radiation therapy is the ideal postoperative irradiation treatment plan in patients with breast cancer (BC). However, there are specific situations such as chest wall (with or without breast reconstruction) and regional node irradiation that still face obstacles in its widespread use. There is a lack of evidence supporting the use of moderately hypofractionated irradiation from the Latin American context. This study aims to describe the profile and clinical outcomes of patients treated with moderate hypofractionation for both early-stage (Stage I and II) and locally advanced BC (Stage III) regardless of the type of surgery in a Brazilian Oncology Center.

Methods

All patients with non-metastatic BC who were treated with moderately hypofractionated schedules of 40Gy in 15 fractions or 42.4Gy in 16 fractions between 2010 to 2019 at Hospital Sírio-Libanês, Brazil were retrospectively analyzed. The rates of local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS), distance recurrence-free survival (DRFS) and overall survival (OS) were estimated. Acute and late toxicity profiles were accessed for the entire cohort.

Findings

A total of 670 patients were included. The median age was 57 years and the median follow-up time was 31 months. Most of the patients had stage I and II breast cancer, and 81.6% underwent breast-conserving surgery. Of the 123 women who underwent mastectomy treatment, 29% (n = 37) had immediate reconstruction with implants and 28% (n = 35) with autologous tissue. Seventy-one per cent of the patients presented luminal subtype tumour and 84.3% received adjuvant hormonal therapy. Chemotherapy was administered to almost half of the patients and all 80 patients with Her-2 positive disease received trastuzumab-based systemic therapy. One-third of patients received regional node irradiation; boost was performed in 41.1% of treatments. The 5-year LRFS, RRFS, DRFS and OS was 95.6%, 97.6%,92.2% and 95.9%, respectively. Acute and late side effects profile were mild and only 2.9% of patients developed grade 3 dermatitis. Among patients with breast implants, 11.4% had capsular contracture.

Interpretation

In this Brazilian institution experience, moderately hypofractionated irradiation to the breast, chest wall (with or without breast reconstruction), and regional lymph nodes was safe and with an acceptable toxicity profile.

Funding

None.

A comparison of timely completion of hypofractionated and traditional adjuvant radiation therapy in early-stage breast cancer: Evidence of impact on reducing racial and socioeconomic disparities

BACKGROUND

Timely completion of adjuvant radiation after breast conservation therapy is associated with decreased mortality and increased disease-free survival. Few data exist comparing timely completion between hypofractionated radiation and traditional radiation at a national level or across racial and socioeconomic cohorts.

METHODS

A retrospective review of the National Cancer Database (2012-2016) on patients undergoing breast conservation therapy for early-stage breast cancer, specifically T1 or T2, N0, M0 patients, was performed. Multivariable logistic regression models were used to compare timely completion of hypofractionated radiation (within 5 weeks of initiation) and traditional radiation (within 7 weeks) across patient, tumor, and facility characteristics.

RESULTS

In total, 210,816 patients met criteria, with 59.4% receiving traditional radiation (n = 125,140) and 40.6% receiving hypofractionated radiation (n = 85,676). Overall, 82.8% of patients achieved timely completion of radiation. Among hypofractionated radiation patients, 94.5% of patients achieved timely completion, whereas only 74.8% of traditional radiation patients achieved timely completion (P < .0001). Regarding race/ethnicity, all groups benefited substantially in timely completion of hypofractionated radiation over traditional radiation. However, both treatment cohorts demonstrated that Black (odds ratio (hypofractionated radiation) = 0.842, odds ratio (traditional radiation) = 0.821) and Hispanic (odds ratio (hypofractionated radiation) = 0.917, odds ratio (traditional radiation) = 0.907) patients had lower odds of timely completion compared to White patients (P < .0001). Lower high school graduation rate, median income for patients' ZIP code, and Medicaid were also associated with lower odds of timely completion for both hypofractionated radiation and traditional radiation (both P < .0001).

CONCLUSION

Timely completion of radiation therapy in breast conservation therapy is greater for patients receiving hypofractionated radiation than traditional radiation across racial and socioeconomic cohorts. Disparities in timely completion were substantially reduced with hypofractionated radiation utilization. However, there are treatment disparities across racial and socioeconomic cohorts that persist in both treatment groups.

Clinical Outcomes of Hypofractionated Whole Breast Irradiation in Early-Stage, Biologically High-Risk Breast Cancer

PURPOSE

Adoption of hypofractionated whole breast irradiation (WBI) for patients with early-stage, biologically high-risk breast cancer remains relatively low. We compared clinical outcomes of conventionally fractionated versus moderately hypofractionated WBI in this patient population.

METHODS

We queried a prospectively maintained database for patients with early-stage (T1-2, N0, M0) breast cancer who received whole breast irradiation with either conventional fractionation (CWBI) or moderate hypofractionation (HWBI) at a single institution. We included only patients with biologically high-risk tumors (defined as either ER/PR/HER-2 negative, HER-2 amplified, and/or patients with a high-risk multi-gene assay) who received systemic chemotherapy. Inverse probability of treatment weighting (IPTW) was used to compare treatment cohorts and to estimate 5-year time to event endpoints. Hazard ratios (HR) and 95% CI were determined based on Cox Proportional Hazards Model.

RESULTS

We identified 300 patients, of whom 171 received CWBI and 129 received HWBI. There was a statistically significant difference in median age at diagnosis, 59 years for CWBI vs 63 years for HWBI (p = 0.004), and in median follow-up time, 97 months for CWBI vs 55 months for HWBI (p < 0.001). After accounting for differences in patient and tumor characteristics with IPTW, we found similar 5-year freedom from local recurrence (HR 0.76, 95% CI 0.14-4.1), freedom from regional recurrence (HR 3.3, 95% CI 0.15-69), freedom from distant metastasis (HR 3.9, 95% CI 0.86-17), and disease-free survival (HR 0.84, 95% CI 0.3-2.4), between those treated with CWBI and those treated with HWBI. Results were similar among each of the three high-risk subtypes.

CONCLUSION

Our data support the use of moderately hypofractionated whole breast irradiation in patients with early-stage, biologically high-risk breast cancer.

Comparative Effectiveness Analysis of 3D-Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy (IMRT) in a Prospective Multicenter Cohort of Patients With Breast Cancer

PURPOSE

Simple intensity modulation of radiation therapy reduces acute toxicity compared with 2-dimensional techniques in adjuvant breast cancer treatment, but it remains unknown whether more complex or inverse-planned intensity modulated radiation therapy (IMRT) offers an advantage over forward-planned, 3-dimensional conformal radiation therapy (3DCRT).

METHODS AND MATERIALS

Using prospective data regarding patients receiving adjuvant whole breast radiation therapy without nodal irradiation at 23 institutions from 2011 to 2018, we compared the incidence of acute toxicity (moderate-severe pain or moist desquamation) in patients receiving 3DCRT versus IMRT (either inverse planned or, if forward-planned, using ≥5 segments per gantry angle). We evaluated associations between technique and toxicity using multivariable models with inverse-probability-of-treatment weighting, adjusting for treatment facility as a random effect.

RESULTS

Of 1185 patients treated with 3DCRT and conventional fractionation, 650 (54.9%) experienced acute toxicity; of 774 treated with highly segmented forward-planned IMRT, 458 (59.2%) did; and of 580 treated with inverse-planned IMRT, 245 (42.2%) did. Of 1296 patients treated with hypofractionation and 3DCRT, 432 (33.3%) experienced acute toxicity; of 709 treated with highly segmented forward-planned IMRT, 227 (32.0%) did; and of 623 treated with inverse-planned IMRT, 164 (26.3%) did. On multivariable analysis with inverse-probability-of-treatment weighting, the odds ratio for acute toxicity after inverse-planned IMRT versus 3DCRT was 0.64 (95% confidence interval, 0.45-0.91) with conventional fractionation and 0.41 (95% confidence interval, 0.26-0.65) with hypofractionation.

CONCLUSIONS

This large, prospective, multicenter comparative effectiveness study found a significant benefit from inverse-planned IMRT compared with 3DCRT in reducing acute toxicity of breast radiation therapy. Future research should identify the dosimetric differences that mediate this association and evaluate cost-effectiveness.

Hypofractionated Radiation Therapy for Breast Cancer: Financial Risk and Expenditures in the United States, 2008 to 2017

PURPOSE

Rising cancer care expenditures and technological advancement of shorter radiation therapy regimens have drawn significant attention to the use of hypofractionated radiation therapy in clinical care. We examine the costs of hypofractionated whole breast irradiation (HF-WBI) compared with conventional whole breast irradiation (CF-WBI) in the United States and investigate the influences of patient characteristics and commercial insurance on HF-WBI use.

METHODS AND MATERIALS

In a retrospective study using private employer-sponsored insurance claims, a pooled cross-sectional evaluation of radiation therapy in patients with commercial insurance was performed from 2008 to 2017. The study population included female patients with early-stage breast cancer treated with lumpectomy and whole breast irradiation.

RESULTS

A total of 15,869 women received HF-WBI, and 59,328 received CF-WBI. HF-WBI use increased from 2008 to 2017. Community-level factors such as a higher proportion of college graduates and greater mixed racial composition were associated with increased HF-WBI use. Mean insurer-paid radiation therapy expenditures were significantly lower for HF-WBI versus CF-WBI (adjusted difference, $6375; 95% confidence interval, $6147-$6603). Mean patient out-of-pocket expenditure for HF-WBI was $139 less than that for CF-WBI. Geographic variation existed across the United States in HF-WBI use (range, 9.6%-36.2%), with no consistent relationship between HF-WBI use and corresponding average cost differences between HF-WBI and CF-WBI.

CONCLUSIONS

If trends continue, HF-WBI will soon become the dominant form of radiation treatment in the United States. Although HF-WBI represents significant savings to the health care system and individual patients, no evidence indicated that a financial disincentive had slowed adoption of HF-WBI. Therefore, multilevel approaches, including individuals, the community, and health policy, should be used to promote cost-effective cancer care. Innovations to policies on cost-effective radiation therapy treatment might consider non-financial incentives to promote HF-WBI use.

The impact of chemotherapy on toxicity and cosmetic outcome in patients receiving whole breast irradiation: an analysis within a state-wide quality consortium

PURPOSE

We investigated whether the use of chemotherapy prior to whole breast irradiation (WBI) using either conventional fractionation (CWBI) or hypofractionation (HWBI) is associated with increased toxicity or worse cosmetic outcome compared to WBI alone.

METHODS AND MATERIALS

We identified 6,754 patients who received WBI alone (without a third field covering the superior axillary and supraclavicular nodal regions) with data prospectively collected in a state-wide consortium. We reported rates of four toxicity outcomes: physician-reported acute moist desquamation, patient-reported acute moderate/severe breast pain, a composite acute toxicity measure (including moist desquamation and either patient-reported or physician-reported moderate/significant breast pain), and physician-reported impaired cosmetic outcome at one year following WBI. Successive multivariable models were constructed to estimate the impact of chemotherapy on these outcomes.

RESULTS

Rates of moist desquamation, patient-reported pain, composite acute toxicity, and impaired cosmetic outcome were 23%, 34%, 42%, and 10% for 2,859 patients receiving CWBI and 13%, 28%, 31%, and 11% for 3,895 patients receiving HWBI. Receipt of chemotherapy prior to CWBI was not associated with higher rates of patient-reported pain, composite acute toxicity, or impaired cosmetic outcome compared to CWBI without chemotherapy but was associated with more moist desquamation (OR=1.32 [1.07-1.63], p=0.01). Receipt of chemotherapy prior to HWBI was not associated with higher rates of any of the four toxicity outcomes compared to HWBI alone.

CONCLUSIONS

In this cohort, use of chemotherapy prior to WBI was generally well tolerated. CWBI with chemotherapy, but not to HWBI with chemotherapy, was associated with higher rates of moist desquamation. Rates of acute breast pain and impaired cosmetic outcome at one year were comparable in patients receiving chemotherapy prior to either CWBI or HWBI. These data support the use of HWBI following chemotherapy.

Radiation Oncology Alternative Payment Model and Large Urban Academic Centers: Future Implications for Patients and Providers

The radiation oncology alternative payment model (RO-APM) was developed by the Center for Medicare and Medicaid Innovation, a part of the Centers for Medicare & Medicaid Services, as a vehicle to optimize value for patients undergoing radiation therapy. By shifting reimbursement away from fee-for-service and toward a prospective bundled payment system, the RO-APM is intended to bend the cost curve in radiation oncology while preserving or even enhancing outcomes. As with prior large-scale policy initiatives, the nature and magnitude of the RO-APM's impact on care delivery will vary substantially depending on a host of local factors, including practice setting. Urban academic centers play a key role in radiation oncology by spearheading innovation, managing the most complicated cases, training the next generation of radiation oncologists, and often caring for vulnerable patient populations. Thus, to protect patients' access to this high-quality cancer care, it will be crucial to characterize the RO-APM's projected impact on large urban academic institutions before its implementation, including possible unintended adverse consequences. Here, we provide an overview of this seismic change in radiation oncology reimbursement and discuss its unique potential implications for large urban academic institutions as a means to facilitate necessary preparations and inform future revisions to the model.

Single institute experience of intraoperative radiation therapy in early-stage breast cancer

Intraoperative radiation therapy (IORT) is an alternative to whole breast irradiation in selected early-stage breast cancer patients. In this single institute analysis, we report the preliminary results of IORT given by Axxent Electronic Brachytherapy (eBT) system.Patients treated with lumpectomy and eBT within a minimum follow-up period of 12 months were analyzed. Eligible criteria include being over the age of 45, having unifocal invasive ductal carcinoma (IDC) or ductal carcinoma in situ <3 cm in diameter, not exhibiting lymph node involvement on preoperative images, and negative sentinel lymph node biopsy. The eBT was given by preloaded radiation plans to deliver a single fraction of 20 Gray (Gy) right after lumpectomy.From January 2016 to April 2019, a total of 103 patients were collected. There were 78 patients with IDC and 25 with ductal carcinoma in situ. At a mean follow-up time of 31.1 months (range, 14.5-54.0 months), the local control rate was 98.1%. Two IDC patients had tumor recurrences (1 local and 1 regional failure). Post-IORT radiotherapy was given to 4 patients. There were no cancer related deaths, no distant metastases, and treatment side effects greater than grade 3 documented.We report the largest single institute analysis using the eBT system in Taiwan. The low recurrence and complication rates at a 31.1 month follow-up time support the use of the eBT system in selected early-stage breast cancer patients.

Long-Term Results of Postoperative Hypofractionated Accelerated Breast and Lymph Node Radiotherapy (HypoAR) with Hypofractionated Boost

We report long-term results (median follow-up 12 years) of hypofractionated accelerated radiotherapy (HypoAR) in patients treated with breast-conserving surgery. In total, 367 women were treated with HypoAR. Axillary and supraclavicular area (ASA) were treated in patients with involved nodes. In total, 290 patients (scheme A) received 3.5 Gy/day ×10 fractions (breast/ASA) followed by two 4 Gy fractions with electrons to the affected breast quadrant within 16 days. In total, 77 patients (Scheme B) received 2.7 Gy/day for 16 consecutive fractions (breast/ASA) within 22 days, while concurrently, the affected breast quadrant received an electron booster dose of 0.8 Gy for the first 13 fractions. Amifostine was offered to 252/367 patients. Early radiation toxicity was minimal. Regarding late toxicities, symptomatic breast edema was noted in 2.2%, asymptomatic breast fibrosis in 1.9%, and arm lymphedema in 3.7% of patients. Amifostine reduced early radiation dermatitis (p = 0.001). In total, 2.2% of patients developed contralateral breast and 1.6% other carcinomas. Locoregional recurrence (LR) occurred in 3.1% of patients (0% for in situ carcinomas). Positive margins after surgery, extracapsular node invasion, and HER2-enriched/triple-negative tumors were linked with significantly worse LR-free survival. The involvement of more than three nodes and luminal type other than A were independent prognostic variables of metastasis and death events. HypoAR delivering a biological dose of 50–52 Gy to the breast/ASA is a safe and effective therapy for patients treated with conservative surgery. The risk of carcinogenesis is low. Positive surgical margins, extracapsular node invasion, and HER2-enriched/triple-negative phenotypes appear as a cluster of features linked with a higher risk for locoregional relapse.

Development and Pilot Implementation of a Remote Monitoring System for Acute Toxicity Using Electronic Patient-Reported Outcomes for Patients Undergoing Radiation Therapy for Breast Cancer

PURPOSE

We aimed to develop and study the implementation of a remote system for toxicity assessment and management of acute side effects of breast radiation using electronic patient-reported outcomes (ePROs).

METHODS AND MATERIALS

A response-adapted Patient-Reported Outcomes Common Terminology Criteria for Adverse Events-based assessment for breast radiation toxicity was administered weekly during and for 8 weeks after radiation from June 2019 to July 2020. The care team received alerts when "severe" symptoms were reported by patients, who were then contacted. Treatment, clinic, and sociodemographic characteristics were abstracted from patient records. A subsample of patients and care team members was qualitatively interviewed at follow-up.

RESULTS

Overall, 5787 assessments were sent to 678 patients, of whom 489 (72%) completed 2607 assessments (45%). Moderate or greater toxicity was reported by 419 responders (86%; 95% CI, 82%-89%). Clinician alerts for severe toxicity were generated for 264 assessments among 139 unique patients, of which 83% occurred posttreatment. The proportion of surveys that prompted an alert was significantly higher after treatment (219 [13%]) than during treatment (45 [5%]) (P < .001). Survey completion rates in the posttreatment period were higher among patients undergoing partial breast irradiation than postmastectomy radiation (incidence rate ratio, 0.70; 95% CI, 0.60-0.81) (P < .001) despite these patients experiencing less severe toxicity. Interviews (15) found that patients had a positive experience with ePROs, although many thought the primary purpose was for research rather than symptom management.

CONCLUSIONS

With the majority of toxicity occurring after breast radiation has ended, remote symptom monitoring with ePROs appears to fill a gap in clinical practice, particularly for patients undergoing shorter courses of radiation. It is important to properly onboard patients and explain that the purpose of ePROs is to aid clinical care. Further research is needed to determine whether the costs associated with ePROs can be offset by reducing routine clinic visits and whether this approach is acceptable and appropriate.