ObjectiveTo investigate effect of resection of primary tumors on overall survival in patients with stage Ⅳ breast cancer.MethodsThe related literatures on the treatment of stage Ⅳ breast cancer in the PubMed, Medline, Cochrane Library, Embase, CNKI, Wanfang Data, CBM, VIP, etc. were comprehensively searched. Two authors independently screened the literatures and extracted data, including the overall survival, progression-free survival and tumor characteristics. The meta analysis was performed using RevMan 5.3 software and SPSS 21.0.ResultsA total of 21 articles were included in this study, including 17 retrospective cohort studies and 4 randomized controlled studies. A total of 5 250 patients with stage Ⅳ breast cancer were included, of which 2 686 patients underwent the local tumor resection+systemic therapy (operation group) and 2 564 patients only received the systemic therapy (non-operation group). The results of meta-analysis showed that the overall survival of the operation group was significantly better than that of the non-operation group [HR=0.64, 95%CI (0.59, 0.69), P<0.000 01], the result of subgroup analysis in the retrospective cohort studies [HR=0.60, 95%CI (0.55, 0.65), P<0.000 01] was consistent with this. However the disease-free survival had no statistical significance [HR=0.43, 95%CI (0.17, 1.11), P=0.08]. The clinicopathologic features of the two groups were further analyzed showed that the patients in the operation group were younger (P<0.05), and the proportions of the patients with T2 stage or below, bone metastasis, ER negative, radiotherapy, or metastatic lymph nodes less than 3 were higher (P<0.05) as compared with the non-operation group.ConclusionsLocal resection of primary tumors in patients with stage Ⅳ breast cancer can improve overall survival. Individualized treatment should be carried out.