Neoadjuvant FOLFOXIRI for locally advanced rectal cancer: A retrospective analysis focusing on long-term anal preservation.

To investigate the safety and efficacy of FOLFOXIRI as neoadjuvant chemotherapy (NAC) for locally advanced rectal cancer (LARC). The outcomes of preoperative and perioperative treatments, as well as long-term outcomes, were retrospectively compared between 26 patients who underwent FOLFOXIRI as NAC for LARC with cT3-4 and/or N+ at our institute between 2015 and 2022, and 31 patients with LARC who underwent neoadjuvant chemoradiotherapy (CAPOX-RT) at our institute between 2011 and 2022. Grade 3 or higher adverse events due to neoadjuvant treatment were significantly more common in the FOLFOXIRI group (11 cases, 42.3 %) than in the CAPOX-RT group (3 cases, 9.7 %), and most of these were neutropenia. Based on the postoperative pathological findings, the complete response rate was significantly lower in the FOLFOXIRI group (1 case, 3.8 %) than in the CAPOX-RT group (7 cases, 22.6 %), but there were no significant differences in the R0 resection rate, survival rate, or relapse-free survival rate. In the CAPOX-RT group, 17 patients (54.8 %) had anal preservation, and during the observation period, 4 patients required stoma construction due to loss of anal function in the late stage. In contrast, in the FOLFOXIRI group, there were no cases of loss of anal function among the 20 patients (76.9 %) who had anal preservation. FOLFOXIRI as NAC requires caution regarding hematological toxicity, but it can be an effective treatment option for patients with LARC who wish to preserve their anus.