Impact of prolonged interval between neoadjuvant chemoradiotherapy and surgery on outcomes in locally advanced rectal cancer: A systematic review and meta-analysis

This study systematically evaluated the impact of delayed surgery after neoadjuvant chemoradiotherapy (nCRT) on the outcomes of locally advanced rectal cancer (LARC). The PubMed, Embase, Cochrane Library, Web of Science, Chinese Biology Medicine, China National Knowledge Infrastructure, WanFang, and Chinese Scientific Journal (VIP) electronic databases were searched from their inception to September 2024 for relevant publications on LARC for which surgery was performed >8 weeks (long interval, LI) and ≤8 weeks (short interval, SI) of nCRT. The included studies were screened and evaluated according to the inclusion and exclusion criteria, and a meta-analysis was performed using RevMan 5.4 software. The search finally yielded 28 studies involving 20,988 patients were included, with 12,176 in the SI group and 8812 in the LI group. While the pathologic complete response (pCR) rate was higher in the LI group than in the SI group, the LI group showed worse overall and disease-free survival. Morbidity, anastomotic leakage rate, operation time, distant metastasis rate, anal preservation rate, and perioperative mortality did not differ significantly between the two groups. The results of this analysis demonstrated that although a longer interval between nCRT and surgery can improve the pCR rate, it may reduce survival outcomes. Owing to limitations in the study number and quality, these findings require further verification by multicenter, large-sample, high-quality randomized controlled trials.