Background: Locally advanced colon cancer can result in serious clinical conditions unless treated appropriately. The aim of this study was to examine the feasibility of en bloc resection and the significance of depth of invasion by analyzing the outcomes of the procedure in colon cancer invading adjacent organs.
Methods: Outcomes of 65 locally advanced colon cancer patients who underwent en bloc resections for contiguous invasion were compared with 285 pT3 colon cancer patients.
Results: En bloc combined resection was performed in 75 patients and 10 (13.3%) of them showed no true malignant infiltration into adjacent organs. In both pT3 and pT4 groups, there was no significant difference in major postoperative complications or mortality. The survival rate of pT4 group was similar to that of pT3 group (5-year rate, 64.0% vs. 72.7%; P = 0.287). In multivariate analysis, lymph node metastasis, lymphovascular infiltration, and perineural invasion were independently associated with patient survival.
Conclusions: The prognosis of colon cancer, even in locally advanced cases, is mainly correlated with nodal status rather than depth of invasion. Therefore, en bloc combined resection in locally advanced colon cancer invading adjacent organs can improve survival as well as local control with acceptable morbidity and mortality.