Influence of preoperative radiotherapy on head and neck free‐flap reconstruction: Systematic review and meta‐analysis

The effect of preoperative external radiotherapy (XRT) on head and neck free‐flap reconstruction is still controversial. In this study, we aimed to determine the impact of preoperative XRT on the outcomes of head and neck microvascular free‐flap reconstruction. A systematic review and meta‐analysis was conducted in concordance with the Systematic reviews and Meta‐Analyses protocol. We searched several databases (PubMed, EMBASE, Web of Science, and Cochrane Library) to find published papers on the topic. The R program was used for data synthesis and statistical heterogeneity evaluation; then, fixed effect or random effect models were used. A total of 37 studies, involving 12 408 patients with 12 668 flaps, were included in this meta‐analysis. The overall flap success rate for all studies was 94.4%. Pooled analysis showed that patients with preoperative XRT were significantly associated with an increased risk of total flap failure (odds ratio [OR] = 1.80, 95% confidence interval [CI] = 1.45‐2.23, P