The standard of care for the treatment of locally advanced rectal cancer (LARC) results in an excellent local disease control but the metastasis rates remain high. PRODIGE 23 demonstrated improved disease-free survival (DFS) and metastasis-free survival (MFS) with total neoadjuvant therapy versus standard of care in this population. Long-term analysis of overall survival (OS) is reported here.

The study design, participants, and primary endpoint DFS have been reported for this multicenter, randomized, open-label, phase III 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 magnetic resonance imaging, and staged cT3/T4. Key secondary endpoints included OS, MFS, and local and metastatic recurrence rate.

With a median follow-up of 82.2 months, the 7-year DFS was 67.6% [95% confidence interval (CI) 60.7% to 73.9%] and 62.5% (95% CI 55.6% to 68.6%) [restricted mean survival time (RMST) difference 5.73 months, 95% CI 0.05-11.41 months, 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% to 84.4%) in the neoadjuvant chemotherapy group and 72.3% (95% CI 65.8% to 77.8%) in the standard-of-care group (RMST difference 6.1 months, 95% CI 0.93-11.37 months, P = 0.021). The 7-year OS was 81.9% (95% CI 75.8% to 86.6%) in the neoadjuvant chemotherapy group and 76.1% (95% CI 69.7% to 81.2%) in the standard-of-care group (RMST difference 4.37 months, 95% CI 0.35-8.38 months, P = 0.033). The safety profile remained unchanged since the previous analysis.

Neoadjuvant chemotherapy with mFOLFIRINOX followed by chemoradiotherapy improved OS, confirmed long-term DFS and MFS benefits in LARC patients, and should be considered as one of the best options of care for these patients.