Abstract
IntroductionStereotactic radiotherapy may improve the prognosis of oligometastatic patients. In the literature, there is very little data available that is specific to breast cancer.Materials and MethodsWe conducted a multicenter retrospective study. The primary objective was to estimate progression-free survival after stereotactic body radiotherapy (SBRT) using Cyberknife of breast cancer oligometastases. The secondary objectives were to estimate overall survival, local control, and toxicity. The inclusion criteria were oligometastatic breast cancer with a maximum of five lesions distributed in one to three different organs, diagnosed on PET/CT and/or MRI, excluding brain metastases and oligoprogressions. This was combined with systemic medical treatment.FindingsForty-four patients were enrolled from 2007 to 2017, at three high-volume cancer centers. The patients mostly had one to two lesion(s) whose most widely represented site was bone (24 lesions or 44.4%), particularly in the spine, followed by liver (22 lesions or 40.7%), then pulmonary lesions (six lesions or 11.1%). The primary tumor expressed estrogen receptors in 33 patients (84.6%); the status was HER2+++ in 7 patients (17.9%). The median dose was 40 Gy (min-max: 15-54) prescribed at 80% isodose, the median number of sessions was three (min-max: 3-10). The median D50% was 42 Gy (min max 17-59). After a median follow-up of 3.4 years, progression-free survival (PFS) at one year, two years, and three years was 81% (95% CI: 66-90%), 58% (95% CI: 41-72%), and 45% (95% CI: 28-60%), respectively. The median PFS was 2.6 years (95% CI: 1.3 – 4.9). Overall survival at three years was 81% (95% CI: 63-90%). The local control rate at two and three years was 100%. Three patients (7.3%) experienced G2 acute toxicity, no grade ≥3 toxicity was reported.ConclusionThe PFS of oligometastatic breast cancer patients treated with SBRT appears long, with low toxicity. Local control is high. SBRT for oligometastases is rarely applied in breast cancer in light of the population in our study. Phase III studies are ongoing.
Highlights
Stereotactic radiotherapy may improve the prognosis of oligometastatic patients
The purpose of our study is to evaluate the contribution of stereotactic body radiotherapy to the management of breast cancer oligometastases in three highvolume Cancer Centers
In the subgroup analysis of patients with breast cancer, Milano et al reported, for 39 cases of breast cancer, a metastasis-free survival at 52% at two years and 36% at six years [11] The strength of our study resides in its homogeneity, as well as the fact that the radiotherapy was exclusively performed in stereotactic conditions, the data from which was reported according to the recommendations in ICRU report 91 [18]
Summary
Stereotactic radiotherapy may improve the prognosis of oligometastatic patients. In the literature, there is very little data available that is specific to breast cancer. The concept of oligometastasis was described in 1995 as an intermediate stage between localized versus generalized disease, in which tumor extension is limited to a small number of metastases, generally less than five, commonly with one to two organ(s) affected [2]. The ESO-ESMO international consensus guidelines for advanced breast cancer (ABC 5) [3] allows for, on the other hand, a maximum of five lesions to define oligometastatic disease, regardless of the number of organs affected. In breast cancer, this stage accounts for 1 to 3% of patients, even if the figures are not sufficiently representative [4]. The use of focal ablative therapies could potentially delay the introduction of systemic therapy, allow for a treatment pause in the case of fully controlled disease, or avoid an early change in treatment line
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
