Meta-analysis on survival rate after post-mastectomy radiotherapy for breast cancer patients with T1-T2 and 1-3 positive lymph nodes

Objective To comprehensively assess the effectiveness of post-mastectomy radiotherapy (PMRT) on the local control and survival of breast cancer patients with T1-T2 and 1-3 positive axillary lymph nodes using Meta-analysis. Methods Searching the documents of the domestic and foreign medical information databases with references to other papers to identify all clinical controlled trials on post-mastectomy radiotherapy versus without irradiation for postoperative breast cancer with T1-T2 and 1-3 positive lymph nodes. Quality assessment of these studies' methodology and date extraction were conducted according to the Cochrane Reviewer's handbook 5.2. Meta-analysis was performed using RevMan 5.2 software. Results There were 14 studies and 4 643 patients enrolled, including 2 080 cases in PMRT group and 2 563 in no- PMRT group. The Meta-analysis showed that there was a significant benefit for PMRT on overall survival rate (OR 1.89, 95% CI 1.55-2.31, P<0.05), disease-free survival (OR 2.16, 95% CI 1.80-2.60, P<0.05), while decreasing the risk of locoregional recurrence (OR 0.22, 95% CI 0.16-0.30, P<0.05) and distant metastasis rate (OR 0.57, 95% CI 0.35-0.94, P<0.05). For further subset analysis, there are statistical significance between ages <40 and ≥40 (OR 0.15, 95%CI 0.05-0.48; OR 0.33, 95%CI 0.13-0.80, P<0.05), stages T1 and T2 (OR 0.48, 95%CI 0.24-0.96; OR 0.53, 95%CI 0.32-0.89, P<0.05) in breast cancer. Conclusions PMRT has benefit for overall survival rate, disease-free survival and significantly reduces the locoregional recurrence rate, distant metastasis rate in patients with T1-T2 tumors with 1-3 positive nodes. PMRT should be considered for patients with T1-T2 tumors with 1-3 positive nodes. Key words: Breast cancer; Axillary lymph nodes; Radiotherapy; Efficacy; Meta-analysis