Accelerated Partial Breast Irradiation in the Elderly:8-year Oncological Outcome and Prognostic Factors

Abstract

Introduction: To evaluate long term clinical outcome and prognostic factors after accelerated partial breast irradiation (APBI) in the elderly using high-dose-rate interstitial multi-catheter brachytherapy (HIBT).Material and methods: Between 2005 and 2018, 109 patients underwent APBI using HIBT (34 Gy/10f/5d or 32 Gy/8f/4d). Based on a prospective database, outcomes were retrospectively analyzed (local relapse-free survival (LRFS), metastatic-free survival (MFS), specific survival (SS) and overall survival (OS). Prognostic factors were investigated. Late toxicity and cosmetic evaluation were reported.Results: With a median follow-up of 97 months [7–159], median age was 81.7 years [58-89]. According to the GEC-ESTRO APBI classification, 72.5%, 11.9% and 15.6% were classified as low, intermediate and high-risk respectively. The histological type was mainly invasive ductal carcinoma (87.1%). The median tumor size was 10 mm [range 1-35]. Eight-year LRFS, SS and OS were 96.7% [95% CI [0.923; 1]), 96.7% [95% CI [0.924; 1] and 72%[95% CI [0.616; 0.837] respectively. In univariate analysis, APBI classification was not cosidered as prognostic factor, whilemolecular classification was prognostic factor for OS (p<0.0001), SS (p=0.007) and MFS (p=0.009) but not for LR (p=0.586). No Grade ³3 late toxicity was observed while 61 patients (88.4%) and 8 patients (11.6%) presented grade 1 and 2 toxicities respectively. Cosmetic outcome was excellent/good for 96.4%.Conclusion: Long-term follow-up confirms that HIBT is safe and effective for elderly early breast cancer. Our results suggest that selected elderly women presenting with high-risk breast cancer could be also considered for APBI.