NRG Oncology RTOG 1014 : 1 Year Toxicity Report From a Phase II Study of Repeat Breast Preserving Surgery and 3D-Conformal Partial Breast Re-Irradiation (3D-CRT PBrI) for In-Breast Recurrence
Mené sur 55 patientes atteintes d'un cancer invasif du sein ou d'un carcinome canalaire in situ ayant récidivé après une radiothérapie du sein entier (durée de suivi : 1 an ; âge médian : 68 ans), cet essai de phase II évalue la faisabilité et la toxicité d'une irradiation partielle du sein par radiothérapie conformationnelle 3D après une lumpectomie
Purpose : Trial**** is a prospective phase II trial of 3D-CRT PBrI following repeat lumpectomy for in-breast recurrence following previous whole breast irradiation (WBI). The primary goal of the trial was to determine the associated toxicity, tolerance and safety of PBrI. Materials and Methods : Eligibility criteria included in-breast recurrence occurring >1 year following WBI, <3cm, unifocal and resected with negative margins. PBrI was targeted to surgical cavity + 1.5 cm; prescription dose of 45 Gy in 1.5Gy BID for 30 treatments was used. The primary objective was to evaluate the rate of grade ≥3 treatment-related skin, fibrosis, and/or breast pain adverse events (AEs), occurring ≤1 year from re-treatment completion. A rate of ≥13% for these AEs in a cohort of 55 patients was determined to be unacceptable, 86% power, 1-sided
α=0.07. Results
:
Between 2010 and 2013, 65 patients were accrued and the first 55 eligible and with 1 year follow-up were analyzed. Median age is 68 years. 22 patients had DCIS and 33 invasive disease; 19
≤1cm, 13 >1 to ≤2cm and 1 >2cm. All patients were clinically node-negative. Systemic therapy was delivered in 51%. All treatment plans underwent quality review for contouring accuracy and dosimetric compliance. All treatment plans scored acceptable for tumor volume (TV) contouring and TV dose volume analysis (DVA). Only 4 (7%) scored unacceptable for organs at risk (OAR) contouring and OAR DVA. Treatment-related skin, fibrosis, and/or breast pain AEs were recorded as grade 1 in 64%, grade 2 in 7% with only 1 (<2%) grade ≥3 and identified as grade 3 fibrosis of deep connective tissue. Conclusion : PBrI with 3D-CRT following second lumpectomy for patients experiencing in-breast failures after WBI is safe and feasible with acceptable treatment quality achieved. Skin, fibrosis and breast pain toxicity was acceptable and grade 3 toxicity was rare.