Total Neoadjuvant Therapy with FOLFOX Followed by Short-Course Radiation in Locally Advanced Rectal Cancer-An Alternative Approach Evaluated in a Single-Center Clinical Trial

Background/Objectives: Total neoadjuvant therapy (TnT) has emerged as a treatment option for locally advanced rectal cancer. Few studies have evaluated specifically the use of chemotherapy and short-course radiation therapy (SCRT) in obtaining a complete clinical response (cCR) or near-complete clinical response (nCR) and offering non-operative management (NOM). This phase II study sequences FOLFOX followed by SCRT with the primary aim of evaluating the rate of cCR or nCR. Methods: Treatment-naïve adults with non-metastatic clinical T2-3N0 or T1-3 with N1-2a rectal adenocarcinoma deemed candidates for total mesorectal excision (TME) were eligible for this open-label, single-arm clinical trial. This trial evaluated TnT with 5-fluorouracil, leucovorin and oxaliplatin (mFOLFOX6) followed by SCRT. The primary endpoint was the rate of cCR or nCR. Those with cCR or nCR after TnT were offered NOM and close surveillance; all others underwent TME. Secondary endpoints included 1-year disease-free survival (DFS), overall survival (OS), and R0 surgical resection rate. Results: Twelve patients of a planned 40 were enrolled with a median follow-up duration of 4.1 years. The study was closed early after results of the OPRA trial suggested a benefit of sequencing radiation prior to chemotherapy when seeking organ preservation. Four of the twelve patients (33%, 95% CI = (9.9%, 65.1%)) achieved cCR or nCR after TnT and underwent NOM; one patient had local regrowth 5.5 months after the completion of TnT and underwent TME. All four were free of disease at time of analysis. The 1-year DFS was 100%. The median OS was not reached. All surgical resections were R0 with no local recurrence after TME. Conclusions: This paper suggests that TnT with FOLFOX followed by SCRT is a safe and effective approach for treating locally advanced rectal cancer. This approach can be considered in select patients. The 33% of patients offered NOM is lower than the published 74% in OPRA, however, suggesting that chemotherapy followed by SCRT may not be the most optimal approach if organ preservation is the primary treatment aim.