Total neoadjuvant therapy with mFOLFIRINOX versus preoperative chemoradiotherapy in patients with locally advanced rectal cancer: long-term results of the UNICANCER-PRODIGE 23 trial

Background The standard of care for the treatment of locally advanced rectal cancer results in an excellent local disease control but the metastasis rates remain high. PRODIGE 23 demonstrated improved disease-free and metastatic-free survival with total neoadjuvant therapy versus standard of care in this population. Long-term analysis of overall survival is reported here. Patients and methods The study design, participants, and primary endpoint disease-free survival (DFS) have been reported for this multicenter, randomized, open-label, phase 3 trial investigating the neoadjuvant chemotherapy with mFOLFIRINOX (6 cycles) followed by chemoradiotherapy, surgery, and adjuvant chemotherapy (6 cycles), versus chemoradiotherapy, surgery, and adjuvant chemotherapy (12 cycles) in patients with locally advanced rectal adenocarcinoma under peritoneal reflection on MRI, and staged cT3/T4. Key secondary endpoints included overall survival (OS), metastasis-free survival (MFS), and local and metastatic recurrence rate. Results With a median follow-up of 82.2 months, the 7-year DFS were 67.6% (95% CI 60.7%-73.9%) and 62.5% (95% CI 55.6%-68.6%) (RMST difference 5.73 months; 95% CI 0.05-11.41; p=0.048) in the neoadjuvant chemotherapy and the standard of care groups, respectively. The 7-year MFS was 79.2% (95% CI 73.0%-84.4%) in the neoadjuvant chemotherapy group and 72.3% (95% CI 65.8%-77.8%) in the standard of care group (RMST difference 6.1 months; 95% CI 0.93-11.37; p=0.021). The 7-year OS was 81.9% (95% CI 75.8%-86.6%) in the neoadjuvant chemotherapy group and 76.1% (95% CI 69.7-81.2) in the standard of care group (RMST difference 4.37 months; 95% CI 0.35-8.38; p=0.033). The safety profile remained unchanged since the previous analysis. Conclusion(s) Neoadjuvant chemotherapy with mFOLFIRINOX followed by chemoradiotherapy improved OS, confirmed long-term DFS and MFS benefits in locally advanced rectal cancer patients and should be considered as a one of the best options of care for these patients.