Comparative Effectiveness of Neoadjuvant Chemotherapy in Locally Advanced Colon Cancer: Evidence from A Propensity Score–Matched Cohort

Neoadjuvant chemotherapy (NAC) has shown value in managing locally advanced colon cancer (LACC). The National Comprehensive Cancer Network lists it as a therapeutic choice for patients with clinical T4b colon cancer. Yet, the long-term survival gains from NAC in LACC remain contested because conclusive clinical trial evidence pinpointing which patients derive the greatest benefit is lacking. The present study set out to determine the effectiveness of NAC in LACC patients, stratified by histological subtype. This retrospective analysis included 3,709 LACC patients who underwent curative resection at Harbin Medical University Cancer Hospital from 2014 through 2018. The cohort was divided into two arms: one receiving neoadjuvant chemotherapy (NAC) and the other adjuvant chemotherapy (AC). Propensity score matching (PSM) was used to balance confounding variables, and survival differences between the two arms across distinct histological subtypes were assessed using Kaplan-Meier (K-M) curves and log-rank testing. Among individuals with non-mucinous adenocarcinoma (NMAC), those managed with NAC achieved markedly superior 5-year OS (76.3% vs. 69.2%, P = .039) and DFS (67.2% vs. 60.1%, P = .041) rates compared with those who received AC. Conversely, within the mucinous adenocarcinoma (MAC) and signet ring cell carcinoma (SRCC) subgroups, overall survival and disease-free survival did not differ significantly between the two treatment modalities. The prognostic utility of NAC in LACC patients was histology-dependent. NMAC may stand as a marker for enhanced long-term survival following NAC in this population.