ESTRO 2024 - Abstract Book

S484

Clinical - Breast

ESTRO 2024

560

Digital Poster

Outcomes of stereotactic body radiotherapy on oligometastatic and oligoprogressive breast cancer

Shreya Armstrong 1 , Andreas Makris 2 , Katherine Belessiotis-Richards 2 , Mohammed Abdul-Latif 2 , Peter Ostler 2 , Nihal Shah 2 , David Miles 3 , Yat Man Tsang 4 1 North Coast Cancer Institute, Radiation Oncology, Lismore, Australia. 2 Mount Vernon Cancer Cancer, Clinical Oncology, Northwood, United Kingdom. 3 Mount Vernon Cancer Cancer, Medical Oncology, Northwood, United Kingdom. 4 Princess Margaret Cancer Centre, Radiation Medicine Program, Toronto, Canada

Purpose/Objective:

Evidence shows stereotactic body radiotherapy (SBRT) is used as a non-invasive ablative therapy in the treatment of multisite oligometastatic (OM) and oligoprogressive (OP) diseases originated from metastatic breast cancer. This study aims to report the treatment outcomes and to investigate what factors that are prognostic in terms of local recurrence free survival (LRFS), progression free survival (PFS) and overall survival (OS) in patients receiving SBRT for extracranial OM and OP diseases originated from metastatic breast cancer.

Material/Methods:

A retrospective review on treatment records of patients with OM and OP from metastatic breast cancer who underwent SBRT at a single institution between February 2010 and October 2019 was carried out. SBRT was performed with daily image guided radiotherapy (IGRT) using a dedicated robotic SBRT machine. LRFS, PFS and OS were calculated using Kaplan-Meier statistics and the post treatment toxicity data was scored following the CTCAE v4.0 protocol. Univariate and multivariate Cox regression tests were used in the subgroup analysis of prognostic factors on LFRS, PFS and OS including patients’ age, types of follow -up imaging (staging CT only vs whole body MR/PET), metastases status (OM vs OP), primary breast cancer tumour grade, hormone receptors (ER/PR/HER2) status, change of systemic treatments at SBRT, number of metastases, SBRT treatment sites and doses.

Results:

56 metastatic breast cancer patients (38 patients with OM and 18 patients with OP) were involved in this retrospective review.