Can internal mammary lymph nodes irradiation bring survival benefits for breast cancer patients? A systematic review and meta-analysis of 12,705 patients in 12 studies

To evaluate the effect of prophylactic irradiation of internal mammary lymph nodes in breast cancer patients. The computer searched PubMed, EMBASE, Web of science, CNKI, Wanfang Medical Network, the Chinese Biomedical Literature Database to find clinical studies on internal mammary lymph node irradiation (IMNI) in breast cancer. The quality of the included literature was evaluated according to the Newcastle-Ottawa scale. Stata14 software was used for meta-analysis. A total of 12,705 patients in 12 articles were included for meta-analyzed. Compared with patients who unirradiated internal mammary lymph nodes (non-IMNI), the risk of death for patients after IMNI was reduced by 11% (HR 0.89, 95% CI 0.79-1.00, P = 0.0470); DFS of group mixed N patients (high risk group) was significantly improved after IMNI (HR 0.58, 95% CI 0.49-0.69, P