Adequate Margins to Prevent Local Re-recurrence of Rectal Cancer: Viewpoint of Pathological Findings

Background: A sufficient surgical margin is critical for preventing re-recurrence and achieving R0 status after resection of a local recurrence of rectal cancer (LRRC).

Patients and methods: Re-recurrence-free survival was analyzed in 110 cases of LRRC according to histological type of primary lesion. The circumferential resection margin (CRM) was classified as 'R1' (x=0 μm), 'R0 shortness' (0 μm <x<2,000 μm), or 'R0 longness' (x≥2,000 μm). The histological change from the primary lesion to the recurrent lesion was classified as 'No change pattern', from well- to moderately-differentiated (W/M) to an expanding lesion; as 'Change pattern', from W/M to an infiltrating lesion.

Results: Re-recurrence-free survival was better in 'R0 longness' than 'R0 shortness' groups and showed that 'No change pattern' cases had considerably better prognosis than 'Change pattern' cases.

Conclusion: Ensuring a CRM >2,000 μm during resection of LRRC is more likely to prevent re-recurrence. Cases with poorly differentiated carcinoma from the primary lesion to the recurrent lesion tend to have poor prognoses.