Role of breast surgery in T1-3 breast cancer patients with synchronous bone metastases

The impact of breast surgery on survival of metastatic breast cancer (MBC) patients is controversial. We addressed the question in a mono-institutional series of MBC patients with synchronous bone metastases. We identified 187 consecutive women diagnosed between 2000 and 2008 with locally operable (T1-T3) MBC, synchronous bone metastases, with no other distant sites being involved. Progression-free survival (PFS) and overall survival (OS) were compared between operated and non-operated patients. Median age was 51 years; 92 % of the women had a hormone-positive tumor. At the time of diagnosis, 131 patients out of 187 (70 %) underwent surgery. Operated and non-operated patients differed in terms of number of bone metastatic sites: a single metastasis was detected in 35 (28 %) operated, and 6 (11 %) non-operated cases (P = 0.01). No other significant differences were observed. The multi-adjusted hazard ratio was 0.63 (95 % CI 0.43-0.92) for PFS and 0.64 (95 % CI 0.41-0.99) for OS in favor of surgery. The 5-year cumulative incidence of ipsilateral breast skin progressions among non-operated patients was 18 %. In this large and homogeneous series of MBC patients with synchronous bone metastases, the role of breast surgery had a favorable impact on both disease progression and mortality.