310PD - The importance of primary surgery in patients with de novo stage IV BC surviving at least 5 years: Protocol MF07-01 randomized clinical trial

Abstract

BackgroundThe MF07-01 trial is a multicenter randomized study comparing locoregional treatment (LRT) followed by systemic therapy (ST) with ST alone in de novo stage IV breast cancer (BC) patients. The aim of this study is to evaluate the importance of LRT in patients who lived at least 5 years after the diagnosis of de novo Stage IV BC. MethodsAt initial diagnosis, patients were randomized 1:1 to either the LRT or ST group. All the patients were given ST either immediately after randomization or after surgical resection of the intact primary tumor. Continuous and categorical variable differences between LRT and ST groups were analyzed using t-test and Chi-square test, respectively. Overall survival (OS) and 5-year survival rates were compared using Kaplan-Meier log-rank tests. Univariate and multivariate Cox models were used to estimate hazard ratios. ResultsDuring 124 months of follow-up, 26% of patients in LRT group and 11% of patients in ST group remained alive. Median survival was 46 months for LRT (n=134) and 35.5 months for ST (n=132) [HR:0.65, 95%CI;0.49-0.85, p=0.002]. Solitary bone metastasis patients’ median survival was 14.5 months longer in the LRT group compared with the ST group [HR:0.53, 95%CI; 0.29-0.98, p=0.04]; 22% of solitary bone metastasis patients in the LRT group and 5% in the ST group were alive. Regarding the patients who lived at least 5 years since randomization, LRT (p=0.004), hormone receptor positivity (p=0.007), hormonotherapy (p=0.0001), bisphosphonates usage (p=0.02), T2 tumor (p=0.0008) and 2 or more organ metastases (p=0.007) were associated with OS in univariate analysis, and in a multivariate Cox proportional model with a significant baseline and clinical characteristics, LRT [OR=1.75, p=0.05)], bisphosphonates usage [OR=1.93, p=0.05), T2 tumor [OR=3.5, p=0.003), and 2 or more organ metastases [OR=0.48, p=0.03] were found to be significantly related with OS. ConclusionsIn the current analysis, patients at the diagnosis of de novo stage IV BC who underwent LRT followed by ST had a 75% higher chance to live at least 5 years compared with the patients who received only ST. Longer follow-up of the study discloses that LRT should be presented to the patient when discussing treatment options. Clinical trial identificationNCT00557986. Legal entity responsible for the studyTurkish Federation of Breast Diseases Societies. FundingTurkish Federation of Breast Diseases Societies. DisclosureAll authors have declared no conflicts of interest.