Close distal margin is associated with locoregional rectal cancer recurrence: A multicenter study

The importance of the radial margin for rectal cancer resection is well understood. However, surgeons have deemphasized the distal margin, accepting very close distal margins to perform sphincter-preserving surgery. We hypothesized that distal margins < 1 cm would be an independent risk factor for locoregional recurrence. The objective was to determine whether close distal margins are associated with increased locoregional recurrence risk.This was a multi-institutional retrospective cohort study conducted at six academic medical centers including patients who received low anterior resection surgery for primary rectal cancer between 2007 and 2018.Of 556 low anterior resection patients, the rate of close distal margin was 12.8% (n = 71), and the locoregional recurrence rate was 5.0% (n = 28). The locoregional recurrence rate for close distal margin cases was 9.9% (n = 7) compared to 4.3% (n = 21) for distal margins ≥1.0 cm. In multivariable analysis, the only factor significantly associated with locoregional recurrence was close distal margin (adjusted odds ratio: 2.80, confidence interval: 1.08-7.25, p = 0.035).Rectal cancer patients with close distal margins (<1 cm) following low anterior resection had a significantly higher risk for locoregional recurrence. Therefore, the decision to perform low anterior resection with margins < 1 cm should be taken with caution.