Clin Oncol (R Coll Radiol). 2024 Oct 29;37:103670. doi: 10.1016/j.clon.2024.103670. Online ahead of print.
ABSTRACT
AIMS: We aimed to evaluate the treatment outcomes and associated prognostic factors in breast cancer (BC) patients who had bone-only oligometastatic disease (OMD) and we tried to determine the subgroup that would benefit most from stereotactic ablative radiotherapy (SABR).
MATERIALS AND METHODS: We enrolled 47 patients with a total of 63 lesions with bone-only oligometastatic BC who underwent SABR for all bone lesions between July 2013 and March 2022. Cases with bone-only metastatic disease with up to 5 metastatic lesions that can be safely treated with SABR were included in this study. All statistical analyses were performed using SPSS 23.0 software (SPSS, Chicago, IL).
RESULTS: The median follow-up time was 34 months. The 2- and 5-year overall survival (OS) rates were 90% and 66%, and the progression-free survival (PFS) rates were 49% and 29%, respectively. The local control rate in the SABR-treated foci was 85%. In multivariate analysis, OMD state (genuine vs. induced), de-novo OMD state (synchronous vs. metachronous), and histology (luminal vs. HER-2 enriched) were prognostic for OS. Molecular subtype switch was observed in 21 (42%) patients, and 0% PFS was observed in 5 years in patients with phenotypic discordance. SABR was well tolerated and there were no ≥grade 4 acute or late toxicities.
CONCLUSION: Our study showed that in patients with bone-only OMD, in HER2-enriched subtypes with genuine & de-novo & synchronous OMD, SABR should be strongly considered for all metastatic foci, especially if there is phenotypic discordance in the primary tumor and metastasis.
PMID:39571205 | DOI:10.1016/j.clon.2024.103670
