ESTRO 2022 - Abstract Book

S1017

Abstract book

ESTRO 2022

All patients with locally recurrent breast cancer, who underwent external beam radiotherapy with PBI until February 2021 at our institution were identified. For each case of reirradiation, demographic, disease characteristics, prior and reirradiation radiotherapy details, toxicity and outcome were collected. Freedom from locoregional recurrence and distant metastasis were calculated using the Kaplan-Meier method. Results Nine patients received BCS plus PBrI for isolated local recurrence. The median prior radiotherapy treatment was WBI with prescribed dose to the breast of 50 Gy (IQR, 48-60 Gy), 9 patients performed 3DCRT technique and 1 patient boost with brachytherapy . The majority (5 patients) had tumor localized on left breast and in the upper outer quadrant. The median time from prior radiotherapy to reirradiation was 89 months (IQR, 28-238 months). Three patients received chemotherapy. The most common reirradiation radiotherapy dose/fractionation was 40 Gy/2.67 Gy fractions per day. One patient received 38.5Gy/3.85 Gy fractions BID. Median reirradiation radiotherapy dose was 40 Gy (IQR, 38.5-60 Gy) in 2.67 Gy/fx (IQR, 2.0-3.85 Gy). There was 1 case of acute grade 3 toxicity: rib fracture in a patient that received 38.5 Gy/3.85 Gy BID. There were no cases of wound dehiscence. Median follow-up was 19.5 months (IQR, 1-52 months) with one patient showing local recurrence 5 months and another patient with distant progression 3 months after reirradiation. Eighteen months after reirradiation one patient showed local and distant progression. The 1 year local relapse-free survival was 87.5% and 1 year distant disease-free survival was 85.7%.