Induction chemotherapy followed by neoadjuvant chemoradiotherapy and surgery for patients with locally advanced rectal cancer: a systematic review and meta-analysis

Background Controversy persists about whether additional induction chemotherapy (ICT) before neoadjuvant chemoradiation (NCRT) yields improved oncological outcomes. We performed a systematic review and meta-analysis to compare ICT+ NCRT+ surgery(S) with NCRT+ S in patients with locally advanced rectal cancer (LARC). Methods We searched the PubMed, EMBASE, Cochrane Library, and China Biology Medicine (CBM) databases. The data were analyzed with Stata version 12.0 software. Results We identified 9 relevant trials that enrolled 1538 patients. We detected no significant difference in the 5-year overall survival (OS) (OR 1.50, 95% CI 0.48-4.64), disease-free survival (DFS) (OR 1.03, 95% CI 0.73-1.46), local recurrence (LR) (OR 0.80, 95% CI 0.45-1.43), and distant metastasis (DM) rates (OR 1.03, 95% CI 0.55-1.93) between patients who did and did not receive ICT. The addition of ICT before NCRT had a similar pathological complete response rate compared to NCRT (OR 1.26, 95% CI 0.90-1.77). Our findings suggest that between the ICT + NCRT+S and NCRT+S groups, ICT improved the incidence of grade 3 to 4 toxicity effects (OR 4.81, 95% CI 2.38-9.37), but between the ICT + NCRT+S and NCRT+S+ adjuvant chemotherapy (ACT) groups, ICT might reduce toxicity (OR 0.19, 95% CI 0.08-0.50). ICT had no significant impact on surgical complications (OR 0.97, 95% CI 0.63-1.51). Conclusions The addition of ICT before NCRT seemingly shows no survival benefit on patients with LARC, and might increase the toxicity.