ESTRO 2024 - Abstract Book

S693

Clinical - Breast

ESTRO 2024

(ERT) as a therapeutic modality. we aimed to evaluate the impact of ERT or a combination of bimodality therapy (BMT; surgery plus radiotherapy) on survival outcomes.

Material/Methods:

A monocentric retrospective study was carried out of patients with De NOVO metastatic breast cancer treated between December 2017 and August 2023. Only patients alive and free from progression under systemic therapy at least 6 months after diagnosis were included. We analyzed data from 50 patients treated with 3D hypofractionated locoregional RT (HLRRT) (40.05 Gy in 15 fractions).The median age was 50,6 years ( 29-76 years ). Thirty patients (60%) underwent BMT and 20 patients (40%) had ERT. The data were analyzed on the Statistical Package for the Social Sciences (SPSS) version 20 (IBM SPSS, Armonk, NY, USA). Overall survival (OS), local recurrence-free survival (LRFS) and metastatic progression-free survival (MPFS) estimates were generated using Kaplan Meier method. Multivariate analysis was performed to evaluate the prognostic value of ERT versur BMT on survival.

Results:

The median follow-up was 41 months [13-89 months]. With 8 deaths reported, the estimated 3-year OS was 73%. Local recurrence was noted in 3 patients (6%) and 12 patients (24%) showed distant metastases. Three-years LRFS and MPFS were respectively 89% and 54 %. there was no significant difference between ERT patients and BMT patients in OS (70.9% vs 57.1% respectively, p=0.37), in LRFS (80% vs 59.7 respectively, p=0.34) and in MPFS (48% vs 51% respectively, p=0.43).

Conclusion:

Overall, local treatment was associated with good outcomes. But there was no statistically significant difference between patients treated with ERT and those who received BMT. radiotherapy alone could be sufficient as local treatment in de novo metastatic breast cancer.

Keywords: Radiotherapy, Metastatic Breast Cancer, Survival

2937

Proffered Paper

Dose deposition in sub-regions of breast relates to acute and persistent pain after radiotherapy

Tanwiwat Jaikuna 1,2 , Fiona Wilson 1 , David Azria 3 , Jenny Chang-Claude 4 , Maria Carmen De Santis 5 , Sara Gutiérrez Enríquez 6 , Marcel van Herk 1 , Peter Hoskin 1 , Maarten Lambrecht 7 , Zoe Lingard 1 , Petra Seibold 4 , Elena Sperk 8 , Paul R Symonds 9 , Christopher J Talbot 9 , Tiziana Rancati 10 , Tim Rattay 9 , Victoria Reyes 11 , Barry S Rosenstein 12 , Dirk de