onc brain

IMPORTANCE: Little is known about regional nodal irradiation (RNI) practice patterns or rates of locoregional recurrence (LRR) with and without RNI in patients with limited nodal disease and favorable biology treated with modern surgical and systemic therapy, including approaches that de-escalate those latter treatments.<br/><br/>OBJECTIVE: To investigate how often patients with low-recurrence score breast cancer with 1 to 3 nodes involved receive RNI, incidence and predictors of LRR, and associations between locoregional therapy and disease-free survival.<br/><br/>DESIGN, SETTING, AND PARTICIPANTS: In this secondary analysis of the SWOG S1007 trial, patients with hormone receptor-positive, ERBB2-negative breast cancer, and a Oncotype DX 21-gene Breast Recurrence Score assay result of no more than 25, were randomized to endocrine therapy alone vs chemotherapy then endocrine therapy. Prospectively collected radiotherapy information was collected from 4871 patients treated in diverse settings. Data were analyzed June 2022 to April 2023.<br/><br/>EXPOSURE: Receipt of RNI (targeting at least the supraclavicular region).<br/><br/>MAIN OUTCOME(S) AND MEASURE(S): Cumulative incidence of LRR was calculated by locoregional treatment received. Analyses were assessed for associations between invasive disease-free survival (IDFS) and locoregional therapy, adjusted for menopausal status, treatment group, recurrence score, tumor size, nodes involved, and axillary surgery. Radiotherapy information was recorded in the first year after randomization, so survival analyses were landmarked as starting at 1 year among those still at risk.<br/><br/>RESULTS: Of 4871 female patients (median [range] age, 57 [18-87] years) with radiotherapy forms, 3947 (81.0%) reported radiotherapy receipt. Of 3852 patients who received radiotherapy and had complete information on targets, 2274 (59.0%) received RNI. With a median follow-up of 6.1 years, the cumulative incidence of LRR by 5 years was 0.85% among patients who received breast-conserving surgery and radiotherapy with RNI; 0.55% after breast-conserving surgery with radiotherapy without RNI; 0.11% after mastectomy with postmastectomy radiotherapy; and 1.7% after mastectomy without radiotherapy. Similarly low LRR was observed within the group assigned to endocrine therapy without chemotherapy. The rate of IDFS did not differ by RNI receipt (premenopausal: hazard ratio [HR], 1.03; 95% CI, 0.74-1.43; P&#x2009;=&#x2009;.87; postmenopausal: HR, 0.85; 95% CI, 0.68-1.07; P&#x2009;=&#x2009;.16).<br/><br/>CONCLUSIONS AND RELEVANCE: In this secondary analysis of a clinical trial, RNI use was divided in the setting of biologically favorable N1 disease, and rates of LRR were low even in patients who did not receive RNI. Disease-free survival was not associated with RNI receipt; omission of chemotherapy among patients similar to those enrolled in the S1007 trial is not an independent indication for use of RNI.

BACKGROUND: Postmastectomy radiation therapy (PMRT) may cause adverse events in the reconstruction setting. Proton-based PMRT is increasingly used and has been shown to improve cardiac and pulmonary dosimetry. Data on the risk of capsular contracture (CC) with proton versus photon PMRT remain scarce. We compared the CC rate of the largest cohort of patients undergoing reconstruction after pencil beam scanning proton PMRT reported to date with an intensity modulated radiation therapy photon cohort, hypothesizing that the proton cohort would have a higher rate of CC.<br/><br/>METHODS AND MATERIALS: An institutional review board -approved retrospective study was conducted on patients with breast cancer who underwent subpectoral 2-stage tissue expander/implant (TE/I) or direct-to-implant (DTI) breast reconstruction and received either pencil beam scanning proton or intensity modulated radiation therapy photon PMRT between January 2017 and December 2023 at 2 centers within a single institution. All patients undergoing TE/I had the TE irradiated. CC rates were estimated using the Kaplan-Meier method. Cox proportional hazards analysis, denoted as hazard ratios (HRs) with 95% CIs, was used to assess variables potentially associated with the outcome, and a binary logistic regression model was used to verify the results.<br/><br/>RESULTS: The study cohort comprised 175 patients (89 proton; 86 photon). The median age was 49 years (range, 24-78), 63% were Hispanic. Patient demographics were well balanced between the groups, except in tumor laterality (P < .001) and reconstruction type (TE/I vs DTI; P < .001). The median follow-up was 42 and 47 months for the proton and photon groups, respectively. In a multivariable analysis, DTI patients had a significantly higher risk of CC compared with TE/I patients (HR, 3.0; 95% CI, 1.7-5.5; P < .001). Proton patients had a higher risk of developing CC compared with the photon group in univariate analysis (HR, 2.3; 95% CI, 1.26-4.30; P = .007), although this effect did not reach statistical significance in the multivariable model (HR, 1.76; 95% CI, 0.93-3.32; P = .083). The 2-year CC rate for patients treated with protons and DTI (n = 36), photons and DTI (n = 15), protons and TE/I (n = 53), and photons and TE/I (n = 71) was 50%, 35%, 23%, 12%, respectively (P < .001). No other factors were significantly associated with CC development.<br/><br/>CONCLUSION: In this contemporary large proton versus photon PMRT cohort, patients treated with proton showed a trend toward an increased risk of CC. Patients undergoing DTI who were treated with protons had the highest risk of CC (50%). Careful consideration of reconstruction and radiation therapy modalities, assessing CC risk, and also involving patient input, is important for treatment selection.