ESTRO 2024 - Abstract Book

S714

Clinical - Breast

ESTRO 2024

Results:

Between 5/2012 and 11/2021, 70 patients were treated with re-PBI. Median follow-up (FU) was 6.3 years (Q1-Q3, 4.0-8.1.). Median age at 1stLR was 62. The median primary BC -1stLR interval was 12.4 years (range: 1.6-26.7). Luminal A-like 1stLR accounted for 41% of the cases and median size was 0.8 cm. At eight years, 26% of the patients showed a subsequent oncologic event: three 2snLRs (corresponding to 8-y CumI rate of 4%), three regional nodal recurrence, 7 distant metastases and 5 other primitive tumors. At 8 years, OS, and DFS were 90% and 76% , respectively. At multivariate analysis, Grade 3 and extensive intraductal component were independent predictors for DFS. For 51/70 patients, 4% grade 3 fibrosis was observed and cosmesis was deemed good/excellent in just over 60% of the cases.

Conclusion:

Re-PBI after repeat BCS represents a feasible alternative to mastectomy with regard to local control, showing an acceptable toxicity profile. A long-term FU is crucial to better understand the pattern of relapse and consolidate the position of re-PBI in clinical practice.

Keywords: Breast Re-RT Recurrence

3026

Digital Poster

Toxicity, Dosimetric & Survival analysis of Ultra-Hypofractionated Radiotherapy for Breast Cancer

Prasad Raj Dandekar, Ajinkya Gupte, Rohan Kadam, Amol Kakade, Mayank Dhoundiyal, Naseem Shaikh

Sir H N Reliance Foundation Hospital and Research Centre, Radiation Oncology, Mumbai, India

Purpose/Objective:

Ultra-hypofractionated (one-week) regimens for adjuvant breast radiotherapy have been found to be non-inferior to moderately hypofractionated regimens (3-weeks). [1] The purpose of this study is to evaluate the dosimetry, toxicity, overall survival (OS) and disease-free-survival (DFS) of breast cancer patients treated with ultra-hypofractionated regimen radiation therapy at a single institute.

Material/Methods:

Between May 2020 and May 2023, this study enrolled Stage I-III breast cancer patients scheduled to undergo ultra hypofractionated adjuvant radiation therapy to the breast/chest wall, along with regional lymph nodes when indicated. Patients who had undergone Modified Radical Mastectomy (MRM) received a planned radiation dose of