The adequacy of the distal resection margin after preoperative chemoradiotherapy for rectal cancer

Aim: The study aimed to determine the adequacy of the distal margin in patients having preoperative chemoradiotherapy (CRT) followed by restorative surgery for rectal cancer. Method: A total of 368 patients with locally advanced rectal cancer treated for cure at our institution between July 1999 and March 2009 were included in the study. All underwent preoperative CRT and sphincter-sparing surgery. The distal margin and other factors were examined for their effect on recurrence and survival. The median duration of follow-up was 48 months. Results: The length of distal margin ranged from 0 to 9.0 cm (median 1.5 cm). The pelvic control and disease-free survival rates at 5 years for patients with a margin of ≤ 3 mm were no different from those in whom it was > 3 mm (P = 0.6 and 0.8). The 5-year pelvic control rates between the ≤ 3 mm and > 3 mm groups were 66.7 and 86.2% in patients with a ypT3-4 tumour (P = 0.049) and 70.0 and 89.1% in patients who showed no response to CRT (P = 0.039). Conclusion: The results suggest that a distal margin of < 3 mm in the surgical specimen after preoperative CRT is associated with a lower rate of pelvic tumour control at 5 years in patients with Stage ypT3-4 tumours or in those who do not respond to CRT.