Oncological Outcomes of Varying Resection Margin Lengths in Colon Cancer Surgery: A Retrospective Analysis.

Background/aim: In colon cancer surgery, the current Japanese guidelines recommend a resection margin of ≥10 cm to prevent local recurrence. However, achieving this length can be difficult in certain clinical scenarios. The optimal resection margin length and its impact on oncological outcomes remain controversial.

Patients and methods: This retrospective study analyzed 148 patients with stage II/III colon cancer who underwent curative laparoscopic resection between 2013 and 2019. Patients were grouped by the shortest resection margin as follows: Group 1 (<5.0 cm), Group 2 (5.0-9.9 cm), and Group 3 (≥10.0 cm). Disease-free survival (DFS) and overall survival (OS) were evaluated using Kaplan-Meier and Cox regression analyses. Propensity score matching (PSM) was applied to minimize selection bias between Groups 2 and 3.

Results: Group 1 had significantly poorer DFS and OS than Groups 2 and 3 (p=0.004 and p=0.0448, respectively). No significant differences in DFS or OS were found between Groups 2 and 3 before or after PSM. After 1:1 matching, DFS and OS remained comparable between the two groups (p=0.9339 and p=0.4857, respectively).

Conclusion: A resection margin ≥5.0 cm was associated with oncological outcomes equivalent to those achieved with margins ≥10.0 cm. Margins of <5.0 cm were linked to poorer survival, suggesting a higher risk of recurrence. These findings support a revision of the rigid 10-cm margin guideline, and suggest that a ≥5.0-cm margin may be sufficient for favorable outcomes in laparoscopic colon cancer surgery.