TNT of SCRT+CAPOX vs SCRT+CAPOXIRI for Locally Advanced Rectal Cancer

Total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC) has the promise, which means non-operative management (NOM) enable more patients (pts) with a complete clinical response (cCR) or near-complete clinical responses (nCR) after TNT to avoid subsequent radical surgery, with potentially maintaining anorectal function and quality of life (QoL). Recently, PRODIGE-23 trial demonstrated that triplet regimen (Irinotecan, oxaliplatin and fluoropyrimidine) before preoperative chemoradiotherapy (CRT) significantly improved outcomes compared with CRT. However, there has been no prospective study comparing consolidation triplet with doublet regimens following short course radiotherapy (SCRT). The aim of this randomized phase III trial is to test superiority of consolidation irinotecan, capecitabine and oxaliplatin (CAPOXIRI) vs. capecitabine and oxaliplatin (CAPOX) following SCRT as TNT in pts with LARC. Pts in both groups will be re-staged after completing TNT before radical surgery according to the Memorial Sloan Kettering Regression Schema; pts with incomplete response (iCR) will undergo total mesorectal excision (TME), cCR pts will receive NOM, and nCR pts will undergo TME or NOM by a physician discretion under the recommendation of blind assessment by the designated NOM central committee. Pts will be followed by CT, MRI, colonoscopy and liquid biopsy every 4 months for 2 years, and every 6 months thereafter up to 5 years. To detect a decrease in 3-year cumulative probability of organ preservation-adapted Disease free survival (DFS) from 75.0% to 81.7%, corresponding to a target hazard ratio of 0·70, a total of 608 pts (196 events) would achieve 70% power at a two-sided α significance level of 0.05.