Multivisceral resection for locally advanced rectal cancer: adequate length of distal resection margin

PURPOSE: Locally advanced rectal cancer may require an intraoperative decision regarding curative multivisceral resection (MVR) of adjacent organs. In bulky tumor cases, ensuring sufficient distal resection margin (DRM) for achievement of oncologic safety is very difficult. This study is designed to evaluate the adequate length of DRM in multiviscerally resected rectal cancer. METHODS: A total of 324 patients who underwent curative low anterior resection for primary pT3-4 rectal cancer between 1995 and 2004 were identified from a prospectively collected colorectal database. RESULTS: Short lengths of DRM (≤1 cm) did not compromise essentially poor oncologic outcomes in locally advanced rectal cancer (P = 0.736). However, especially in rectal cancers invading adjacent organs, DRM of less than 2 cm showed poor survival outcome. In 5-year and 10-year survival analysis of MVR, a shorter DRM (<2 cm) showed 41.9% and 30.5%, although a longer DRM (≥2 cm) showed 72.4% and 60.2% (P = 0.03, 0.044). In multivariate analysis of MVR, poorly differentiated histology, ulceroinfiltrative growth of tumor, and short DRM (<2 cm) were significant factors for prediction of poor survival outcome, although short DRM was not significantly related to local and systemic recurrence. CONCLUSION: In locally advanced rectal cancer of pT3-4, a short length of DRM (≤1 cm) did not compromise essentially poor oncologic outcome. In rectal cancers invading adjacent organs and requiring MVR, a shorter DRM (<2 cm) was found to be related to poor survival outcome.