RESUMEN
BACKGROUND: Neoadjuvant radiation and oxaliplatin-based systemic therapy (total neoadjuvant therapy-TNT) have been shown to increase response and organ-preservation rates in localized rectal cancer. However, trials have been heterogeneous regarding treatment protocols and few have used a watch-and-wait (WW) approach for complete responders. This trial evaluates if conventional long-term chemoradiation followed by consolidation of FOLFIRINOX increases complete response rates and the number of patients managed by WW. METHODS: This was a pragmatic randomized phase II trial conducted in 2 Cancer Centers in Brazil that included patients with T3+ or N+ rectal adenocarcinoma. After completing a long-course 54 Gy chemoradiation with capecitabine patients were randomized 1:1 to 4 cycles of mFOLFIRINOX (Oxaliplatin 85, irinotecan 150, 5-FU 2400)-TNT-arm-or to the control arm, that did not include further neoadjuvant treatment. All patients were re-staged with dedicated pelvic magnetic resonance imaging and sigmoidoscopy 12 weeks after the end of radiation. Patients with a clinical complete response were followed using a WW protocol. The primary endpoint was complete response: clinical complete response (cCR) or pathological response (pCR). RESULTS: Between April 2021 and June 2023, 55 patients were randomized to TNT and 53 to the control arm. Tumors were 74% stage 3, median distance from the anal verge was 6 cm, 63% had an at-risk circumferential margin, and 33% an involved sphincter. The rates of cCR + pCR were (31%) for TNT versus (17%) for controls (odds ratio 2.19, CI 95% 0.8-6.22 P = .091) and rates of WW were 16% and 9% (P = ns). Median follow-up was 8.1 months and recurrence rates were 16% versus 21% for TNT and controls (P = ns). CONCLUSIONS: TNT with consolidation FOLFIRINOX is feasible and has high response rates, consistent with the current literature for TNT. This trial was supported by a grant from the Brazilian Government (PROADI-SUS - NUP 25000.164382/2020-81).