Circumferential resection margin and local recurrence after rectal cancer surgery: a population-based study cohort

Aim: Studies have suggested that there is a difference in risk of local recurrence(LR) with circumferential resection margins (CRM) less than 1.0 mm. We aimed toexamine how exact resection margins affect LR risk.
Method: Data from the Swedish Colorectal Cancer Registry (SCRCR) were usedfor retrospective analysis of resected rectal cancers between 2005 and 2013. Primaryendpoint was LR.
Results: 12146 cases were identified of which 8666 cases were analysed after exclusion. 388 cases had CRM < 1.0 mm and 8278 cases CRM ≥ 1.0 mm. There were 42LR (11.4%) when CRM < 1.0 mm and 280 LR (3.5%) when CRM ≥ 1.0 mm. LRrate was 17% (n = 27/159), 7.1% (n = 15/210), 5.5% (n = 26/473) and 3.4%(n = 254/7550) when CRM was 0.0 mm, 0.1–0.9 mm, 1.0–1.9 mm andCRM ≥ 2 mm respectively. LR risk at CRM 0.0 mm was significantly increased compared to all other groups. No significant difference in LR between CRM 1.0–1.9 mm and ≥ 2 mm was observed. LR was diagnosed earlier when CRM < 1.0 mm.
Conclusion: LR risk is related with accuracy to the surgical circumferential resec-tion margin distance. There was no difference in LR risk above CRM 1.0 mm.Most LRs occurred within two years after surgery when CRM was below 1.0 mm