Abstract

Puttiporn Naovaset66315* and Weerapat Suwanthanm66317

Background and objectives: A 1 cm Distal Resection Margin (DRM) was recommended. Controversy still exists if we can obtain DRM less than 1 cm who had preoperative Chemoradiotherarpy (CRT). Our study aimed to determine the clinical outcomes who had subcentimeter DRM.

Methods: 740 patients with rectal cancer were assessed. 145 patients with rectal cancer underwent curative resection after preoperative CRT were included. The median follow-up time was 28 months.

Results: 36 (24.8%) patients had DRM <1 cm. Local recurrence occurred in 27 patients (18.6%). Overall recurrence was significantly higher in patients with DRM ≤ 0.4 cm than DRM >0.4 cm (50% vs. 16.1%; p=0.015). Moreover, patients who had DRM ≤ 0.4 cm were significantly associated with higher local recurrence than systemic recurrence (p=0.037). Disease Free Survival (DFS) of patients with DRM >0.4 cm was significantly higher than that of patients with DRM ≤ 0.4 cm (p=0.002). In patients with DRM <0.5 cm and >0.5 cm, there were no statistically significant differences in recurrence (p=0.068) and DFS (p=0.107).

Conclusion: The results suggest that cutoff point at 0.5 cm was a minimally acceptable DRM. Minimizing DRM to <1 cm to increase chance of sphincter-saving. Intense adjuvant therapy should be used in these patients to reduce recurrence.