Neoadjuvant chemotherapy in patients undergoing colonic resection for locally advanced nonmetastatic colon cancer: A nationwide propensity score matched cohort study

Abstract

Aim: Neoadjuvant chemotherapy (NCT) for nonmetastatic colon cancer is not routinely used, and is currently only recommended as a treatment option for a subgroup of patients with T4b colon cancers in clinical guidelines. However, NCT may cause downstaging of the tumour, increase resectability, eradicate micrometastases and thereby improve long-term outcomes for patients with nonmetastatic colon cancer. The aim of this study was to investigate the short-term postoperative outcomes in a nationwide cohort of patients with locally advanced colon cancer (LACC) receiving NCT.

Method: Using the Danish Colorectal Cancer Group Database, data were retrieved on patients diagnosed with LACC (defined as clinical T3 with extramural tumour invasion >5 mm or T4) and treated with resection with a curative intent between 2015 and 2019. Propensity score matching (PSM) in a 1:1 ratio was performed to compare short-term surgical and oncological outcomes in patients receiving NCT with patients operated on without receiving NCT.

Results: A total of 179 LACC patients were treated with NCT and 1131 were not. After PSM, 145 patients remained in each group. We found no significant differences in any short-term postoperative outcomes between the two groups. We found significant differences in favour of NCT regarding radicality and pathological N category [86% vs. 81% R0 (P = 0.029) and 51% vs. 46% pN0 (P = 0.017), respectively].

Conclusion: Neoadjuvant chemotherapy for LACC does not result in worse short-term postoperative outcomes and may increase the R0 rate as well as node-negative disease. Results on long-term benefits including survival are awaited from several ongoing randomized controlled trials.

Keywords: colon cancer; nationwide cohort study; neoadjuvant chemotherapy; propensity score matching; short-term outcomes.