Effect of Pathological Response After Neoadjuvant Chemotherapy on Long-term Outcomes in Locally Advanced Colorectal...

Few studies have examined how the response to neoadjuvant chemotherapy (NAC) for locally advanced colorectal cancer affects prognosis.

A total of 162 patients who received NAC followed by radical resection with curative intent between April 2016 and December 2024 were included. Patients were classified into two groups: good response (n=43) and poor response (n=119). Clinicopathological characteristics and prognosis were compared between the groups.

The good response group had a lower rate of combined resection of adjacent organs (11.6% vs. 25.2%, p=0.046), higher clinical N status before NAC (93.0% vs. 71.4%, p=0.002), lower pathological T4 rate (2.3% vs. 23.5%, p<0.001), and less lymphovascular invasion (30.2% vs. 68.9%, p<0.001). Median follow-up duration was 41 months (range=1-66 months). Good responders tended to have better relapse-free survival (RFS; 83.7% vs. 70.5%; p=0.092). Overall survival was similar between the groups (88.6% vs. 78.6% p=0.629). In the poor response group, patients who received adjuvant chemotherapy had significantly better RFS than those who did not (67.3% vs. 70.1%, p<0.05).

Patients with a good response to NAC tended to have a better prognosis. Adjuvant chemotherapy might improve outcomes in patients with poor response to NAC.