The aim of this randomized clinical trial was to evaluate the overall survival (OS) data of patients diagnosed with de novo stage IV breast cancer (BC) who received locoregional treatment (LRT) over a 10-year follow-up.

The MF07-01 is a 1:1 multicenter, randomized clinical trial comparing the LRT with systemic therapy (ST), where ST was given to all patients either immediately after randomization or after surgical resection of the intact primary tumor.

A total of 278 patients were randomized and 265 patients were in the final analysis. At 10-year follow-up, survivals were 19% (95% CI 13%-28%) and 5% (95% CI 2%-12%) in the LRT group and ST group, respectively. Median survival was 46 months for the LRT group and 35 months for the ST group, and hazard of death was 29% lower in the LRT group compared with the ST group (hazard ratio [HR] 0.71; 95% CI 0.59-0.86; p = 0.0003).

Patients with a diagnosis of de novo stage IV BC who underwent LRT followed by ST had a 14% higher chance of OS by the end of the 10-year follow-up compared with the patients who received only ST. The longer study follow-up revealed that LRT should be presented to patients when discussing treatment options.