NRG-BR007: A phase III trial evaluating de-escalation of breast radiation (DEBRA) following breast-conserving surgery (BCS) of stage 1, hormone receptor+, HER2-, RS ≤18 breast cancer

TPS613

Background: Approximately 50% of newly diagnosed breast cancers are stage 1, with the majority being ER/PR-positive, HER2-negative. Genomic assays such as the Oncotype DX® have identified patients (pts) with reduced risk of distant metastasis and without benefit from chemotherapy added to endocrine therapy, freeing them from excess toxicity. Genomic assays are also recognized as prognostic for in-breast recurrence (IBR) after BCS and could similarly allow de-escalation of adjuvant radiotherapy (RT). Reducing overtreatment is of interest to pts, providers, and payers. Methods: We hypothesize that BCS alone is non-inferior to BCS plus RT for in-breast recurrence and breast preservation in women intending endocrine therapy (ET) for stage 1 breast cancer (ER &/or PR positive, HER2-negative with an Oncotype DX Recurrence Score [RS] of ≤18). Stratification is by age (<60; ≥60), tumor size (≤1 cm; >1-2cm), & (RS <11, RS 11-18). Pts are randomized post-BCS to Arm 1 with breast RT using standard methods (hypo- or conventional-fractionated whole breast RT with/without boost, APBI) with ≥5 yrs of ET (tamoxifen or AI) or Arm 2 with ≥5 yrs of ET (tamoxifen or AI) alone. The specific regimen of ET in both arms is at the treating physician’s discretion. Eligible pts are stage 1: pT1 (2 cm), pN0, age ≥50 to <70 yrs, s/p BCS with negative margins (no ink on tumor), s/p axillary nodal staging (SNB or ALND), ER &/or PR positive (ASCO/CAP), HER2-negative (ASCO/CAP), and Oncotype DX RS of ≤18 (diagnostic core biopsy or resected specimen). Primary endpoint is in-breast recurrence. Secondary endpoints are breast conservation rate, invasive in-breast recurrence, relapse-free interval, distant disease-free survival, overall survival, patient-reported breast pain, patient-reported worry about recurrence, and adherence to ET. We assume a clinically acceptable difference in of 4% at 10 yrs to judge omission of RT as non-inferior (10-yr event-free survival for RT group is 95.6% vs 91.6% for the omission of RT group). The study is powered to detect a non-inferiority with 80% power and a one-sided α=0.025, assuming that there would be a ramp-up in accrual in the first two years (leveling off in Yrs 3-5); 1,670 (835 per arm) pts are required to be randomized. Conservative loss to follow-up is 1% per yr. Some of the T1a pts screened may have Oncotype DX scores >18, making them ineligible for the study. In the accrual process, pts will be required to register (1,714 pts) to ensure that our final randomized cohort is 1,670 pts. Current accrual (2-2-2022) is 52 screened and 45 randomized. Support: U10CA180868, -180822, NCT04852887. Clinical trial information: NCT04852887.

What drives overtreatment? Surgeon and radiation oncologist views on omission of adjuvant radiotherapy for elderly women with early stage breast cancer

562

Background: Although trials have shown no survival advantage and only a modest improvement in local control from adjuvant radiotherapy after lumpectomy in older women with stage I, ER+ breast cancer, radiotherapy is commonly administered, raising concerns about overtreatment. Therefore, we sought to evaluate physician attitudes, knowledge, communication, and recommendations in this scenario. Methods: We mailed a survey to a national sample of 713 radiation oncologists and 879 surgeons between June to October 2015. Of these, 913 responded (57%). We assessed physicians’ attitudes, knowledge of pertinent risk information, and responses to clinical scenarios. Results: In patients age > = 70 with stage I, ER+ breast cancer treated with lumpectomy and endocrine therapy, omission of radiotherapy was felt to be unreasonable by 40% of surgeons and 20% of radiation oncologists (p < 0.001). Many surgeons (29%) and radiation oncologists (10%) erroneously associated radiotherapy in older women with improvement in survival. Similarly, 32% of surgeons and 19% of radiation oncologists tended to substantially overestimate the risk of locoregional recurrence in older women with omission of RT. In a scenario with an 81-year-old with multiple comorbidities, 31% of surgeons and 35% of radiation oncologists would still recommend radiotherapy. On multivariable analysis, erroneous attribution of a survival benefit to radiotherapy (OR 6.2; 95% CI 3.9-9.8) and overestimation of remaining life expectancy (OR 6.5; CI 4.2-9.9) were strongly associated with the opinion that radiotherapy omission is unreasonable. Conclusions: Many radiation oncologists and surgeons continue to consider omission of radiotherapy as substandard therapy. A sizeable proportion of surgeons overestimate radiotherapy’s benefits and consider omission of radiotherapy to be an unreasonable departure from the standard of care, suggesting that surgeon involvement in decisions about radiotherapy omission may be a key factor in reducing overuse of aggressive care in this setting.

Management of worry about recurrence in breast cancer survivors

21

Background: Worry about recurrence is a significant concern for breast cancer survivors. We explored physicians‘ confidence and practices in identifying and managing worry. Methods: We surveyed a random sample of 1,500 surgeons and medical oncologists drawn from the AMA Masterfile in 2012. Physician responses to questions regarding their confidence were stratified by practice specialty and compared using the Wilcoxon rank-sum test. Correlates of use of each strategy for managing worry were modeled using multiple variable logistic regression. Results: 896 physicians (59.7%) responded: 498 surgeons and 398 medical oncologists, of whom 85.5% saw breast cancer patients. 62% reported initiating discussions regarding worry about recurrence. Overall, medical oncologists reported more confidence than surgeons in their ability to present risk information to patients, identify survivors with high levels of worry, and help patients manage their worry (p<0.001). Of note, 40.2% of physicians reported low levels of confidence managing worries surrounding recurrence. Confidence presenting risk information was significantly associated with treatment volume, which was highest with >50 cases/year. Surgeons who routinely followed breast cancer survivors for >3 years reported higher confidence; no such correlation existed among medical oncologists, but >90% of this group routinely followed patients for >3 yrs. Female physicians were significantly more likely to report being able to identify survivors with high levels of worry. Practice in an academic setting demonstrated associations with increased confidence. Use of worry management strategies varied by specialty. Medical oncologists were more likely to prescribe medication, address concerns in detail themselves, or refer to a psychologist or social worker. Longer follow-up was associated with increased likelihood of physicians addressing concerns themselves. Conclusions: A sizeable minority of physicians lack confidence in their ability to identify and manage worry in cancer survivors. Medical oncologists and surgeons differ significantly in their approach to worry management, suggesting that greater attention toward this issue in training and continuing education may be warranted.