Is total neoadjuvant treatment beneficial for locally advanced rectal cancer? a meta-analysis of randomized controlled trials

Background: Total neoadjuvant therapy (TNT) is a new strategy combining neoadjuvant therapy and chemotherapy to enhance tumor shrinkage and systemic control. Its effectiveness remains debated.Objectives: This study conducts a meta-analysis of randomized controlled trials (RCTs) to assess TNT's impact and provide high-quality evidence for rectal cancer treatment decisions.Method: We searched China National Knowledge Infrastructure, VIP Database, Wanfang Database, China biomedical literature database, PubMed database, Embase database, and The Cochrane Library for RCTs comparing TNT with neoadjuvant chemoradiotherapy (CRT) in locally advanced rectal cancer. The included trials were screened and assessed for quality based on inclusion and exclusion criteria, and meta-analysis was performed using RevMan 5.3 software.Results: A total of 11 RCTs reported in 14 articles, with 1624 cases in the TNT group and 1541 cases in the CRT group. The results of the meta-analysis showed that compared with the CRT group, the TNT group had a higher pathological complete response rate (RR=1.65, 95% CI [1.40, 1.94], P<0.00001), higher T0 downstaging rate (RR=1.51, 95% CI [1.29, 1.77], P<0.00001), higher 3-year overall survival (HR=0.81, 95% CI [0.67, 0.98], P=0.03), and higher 3-year disease-free survival (HR=0.82, 95% CI [0.70, 0.95], P=0.008). However, there was no statistically significant difference between the two groups in terms of R0 resection rate (RR=1.02, 95% CI [0.99, 1.05], P=0.14), sphincter preservation rate (RR=0.94, 95% CI [0.88, 1.01], P=0.12), anastomotic leakage rate (RR=1.42, 95% CI [0.85, 2.38], P=0.18), and grade 3 or higher adverse events (RR=1.21, 95% CI [0.95, 1.54], P=0.13).Conclusions: In the treatment of locally advanced rectal cancer, TNT offers greater survival benefits compared to neoadjuvant CRT and does not significantly increase the incidence of adverse events. However, further data and studies with long-term outcomes are still required.