Breast radiotherapy as part of loco-regional treatments in stage IV breast cancer patients with oligometastatic disease

Background: Local treatments seem to improve metastasis progression-free survival (MPFS) and overall survival (OS) when added to systemic therapies in stage IV breast cancer. Methods: From 1990 to 2003, we reviewed 9138 cases treated and registered in the Institut Gustave-Roussy breast cancer database. Among them, 308 had presented with stage IV disease. Eighty percent of patients (n = 239) had received a loco-regional treatment and they were categorized into two groups: loco-regional radiotherapy (LRRT) alone (Group 1; n = 147) or breast and axillary surgery ± LRRT (Group 2; n = 92). Results: The median follow-up was 6.5 years. LRRT obtained a long-standing loco-regional clinical response in 85% of patients. The 3-year MPFS rates were 20% in Group 1 and 39% in Group 2; the 3-year OS rates were 39% and 57%, respectively. However, no significant differences in MPFS or OS were observed between the two groups when adjusted on prognostic factors. Conclusions: Radiation therapy alone provides long-standing local control and yields MPFS and OS rates equivalent to those obtained when radiation therapy is combined with surgery, whatever the prognostic factors. Loco-regional therapies, especially radiation therapy alone, may have an important role to play in the treatment of selected patients with stage IV breast cancer.