[Efficacy and safety of total neoadjuvant therapy versus neoadjuvant chemoradiotherapy in the treatment of locally advanced rectal cancer: a meta-analysis].

Objective: To systematically evaluate the efficacy and safety of total neoadjuvant therapy (TNT) in the comprehensive treatment of locally advanced rectal cancer. Methods: Literatures were screened from PubMed, Embase, Web of Science, Cochrane Library, CBM, Wanfang Data, VIP and CNKI from the inception date to May 2021 to collect the randomized controlled clinical trials (RCTs) of TNT followed by total mesorectal excision (TME) versus neoadjuvant chemotherapy (nCRT) followed by TME in the treatment of locally advanced rectal cancer. The data of overall survival, disease-free survival, R0 radical resection rate, pathological complete response (pCR) rate, T downstaging rate, the incidence of adverse events ≥ grade III, including neutropenia, nausea and vomiting, diarrhea, radiation dermatitis and nervous system toxicity, and the morbidity of complications within postoperative 30 days of the two groups were extracted from the included literatures. Review Manager 5.3 software was utilized for statistical meta-analysis. Results: Nine RCTs were finally enrolled including 2430 patients. Meta-analysis results showed that compared with nCRT group, patients in TNT group had longer overall survival (HR=0.80, 95%CI: 0.65-0.97, P=0.03) and higher pCR rate (RR=1.73, 95%CI: 1.44-2.08, P<0.01) with significant differences. Besides, there were no significant differences between two groups in disease-free survival (HR=0.86, 95%CI:0.71-1.05, P=0.14), R0 radical resection rate (RR=1.02, 95%CI: 0.99-1.06, P=0.17) and T downstaging rate (RR=1.04, 95%CI: 0.89-1.22, P=0.58) between two groups. In terms of treatment safety, the incidence of adverse events ≥ grade III (RR=1.09, 95%CI: 0.70-1.70, P=0.70) and morbidity of complications within postoperative 30 days (RR=1.07, 95%CI: 0.97-1.18, P=0.19) did not significantly differ between two groups. Conclusions: In the treatment of locally advanced rectal cancer, TNT may bring more survival benefits than nCRT and does not increase the incidence of adverse events and postoperative complications. Therefore, TNT could be used as a recommended treatment for patients with locally advanced rectal cancer.