The impact of neoadjuvant chemotherapy on safety and long-term survival in patients with locally advanced colon cancer.

[BACKGROUND] Neoadjuvant chemotherapy (NAC) has proven effective for various tumors and is increasingly being adopted as the standard of care for many cancer types. However, its role in the management of locally advanced colon cancer (LACC) remains uncertain. This study aims to evaluate the feasibility and efficacy of NAC in patients with LACC.

[METHODS] We retrospectively reviewed patient records from a prospective database of individuals who underwent colon surgery between January 2015 and May 2019. Among 1,879 patients, 143 received NAC. To minimize selection bias and ensure comparability between groups, a 1:2 propensity score matching (PSM) was performed between the NAC and upfront surgery groups.

[RESULTS] After matching, the NAC group included 134 patients and the upfront surgery group included 268 patients, showing no significant differences in baseline demographic and oncological characteristics. In the NAC group, 16 (11.9%) achieved a pathological complete response (TRG 0), 26 (19.4%) had a moderate response (TRG 1), 55 (41.0%) showed a minimal response (TRG 2), and 37 (27.6%) had a poor response (TRG 3). The R0 resection rate was higher in the NAC group at 97.8% (131/134) compared to 92.5% (248/268) in the upfront surgery group. The rates of severe postoperative complications, bowel function recovery, length of hospital stay, and 30-day readmission were similar between the groups. The 5-year disease-free survival (DFS) rate was significantly higher in the NAC group than in the upfront surgery group (75.2% vs. 63.4%,  = 0.034). However, the 5-year overall survival (OS) rates were 80.4% in the NAC group and 76.3% in the upfront surgery group, with no statistically significant difference ( = 0.098).

[CONCLUSION] NAC increases R0 resection and 5-year DFS rates in LACC patients without elevating the risk of severe postoperative complications, demonstrating its safety and feasibility.