ObjectiveTo evaluate the effect of post mastectomy radiation therapy (PMRT) on breast reconstruction after mastectomy in breast cancer patients, in order to provide evidence support for clinical treatment decision.MethodsFive databases searched in the current study include the Cochrane Library, PubMed, CNKI, VIP and WanFang database. A systematic search for control trials was performed in each database from the starting date of each database to March 1, 2021. After the two evaluators independently selected literatures, extracted data and conducted quality evaluation according to the inclusion and exclusion criteria, the meta analysis was carried out by Revman 5.3 software.ResultsA total of 9 cohort studies (3 447 cases) were included, including 699 cases in PMRT group and2 748 cases in non-radiotherapy group. The results of meta-analysis showed that: PMRT was associated with significant increase in capsular contracture. The incidence of capsular contracture increased from 4.34% in the non-radiotherapy group to 34.10% in patients receiving PMRT [OR=9.25, 95%CI (3.76, 22.78), P<0.000 01]. In addition, PMRT was associated with a significant increase in incidences of reconstructive failure [OR=2.55, 95%CI (1.74, 3.74), P<0.000 01] and revisional surgery [OR=2.24, 95%CI (1.58, 3.18), P<0.000 01]. Moreover it was associated with a significant reduction in patient satisfaction [OR=0.29, 95%CI (0.15, 0.57), P=0.000 30] and cosmetic outcome [OR=0.26, 95%CI (0.15, 0.43), P<0.000 01].ConclusionThis meta-analysis demonstrates that breast cancer patients who received PMRT after breast reconstruction, the rate of adverse events is increased and patients’ satisfaction and cosmetic outcome are decreased.