Real-world effectiveness of total neoadjuvant therapy in locally advanced rectal cancer: a multicenter retrospective study

Abstract

Background This study aims to evaluate the effectiveness and real-world applicability of total neoadjuvant therapy (TNT) in patients with locally advanced rectal cancer (LARC), focusing on pathological complete response (pCR) and disease-free survival (DFS) across different chemotherapy regimens. Methods In this multicenter retrospective study, patients treated between January 2019 and January 2023, 437 patients with locally advanced rectal cancer who underwent total neoadjuvant therapy followed by surgery were analyzed. Standard fluoropyrimidine-based chemotherapy regimens (CAPOX, FOLFOX, or FOLFIRINOX) were used according to institutional practice, and long-course chemoradiotherapy constituted the predominant radiotherapy approach. Patients were grouped based on chemotherapy sequencing as induction, consolidation, or sandwich regimens. Outcomes were evaluated using multivariable logistic regression for pathological complete response and Kaplan-Meier analysis with Cox proportional-hazards modeling for disease-free survival.The median follow-up duration was 66 months. Results The overall pCR rate was 26.3% (n = 115). pCR rates did not differ significantly between induction, sandwich, and consolidation chemotherapy regimens. A longer interval (> 8 weeks) between radiotherapy and surgery was associated with a higher likelihood of achieving pCR. In contrast, cT4 disease and baseline CEA levels > 3 ng/ mL were associated with lower pCR rates.The estimated 3-year disease-free survival (DFS) rate was 83.8%. Recurrence rates within 3 years were numerically higher in patients receiving induction and sandwich regimens compared with consolidation chemotherapy, although these differences did not reach statistical significance. In multivariable analysis, poor tumor regression grade, ypT4 stage, ypN + disease, and post-TNT CEA >= 3 ng/mL were independently associated with an increased risk of recurrence. Conclusion TNT is effective and feasible in real-world settings, achieving pCR and DFS outcomes comparable to clinical trials. No statistically significant differences were observed in pCR or recurrence rates between induction, consolidation, and sandwich chemotherapy regimens. Prospective phase III trials are needed to compare DFS and OS outcomes across these treatment strategies.