The Incidence of Metachronous Colorectal Cancer after Surgical Resection of Left and Right Sides Colon

[ABSTRACT] [Background] : The increase in the amount of secondary bile acids into the colon has been reported as a cause of the increased incidence of colorectal cancer in rats. After completing digestion, bile acids are reclaimed in the terminal ileum by ileal bile acid transporter. We have hypothesized that resection of the terminal ileum increases the risk of metachronous colorectal cancer. Therefore, to assess this hypothesis, the present study compared the incidence of metachronous colorectal cancer in patients who had undergone resection of the right side or the left side of the colon. [Methods] : From January 2005 through December 2012, the medical records of 141 patients with colorectal cancer who had undergone curative resection (RO) at our hospital were reviewed. The final participants were patients who had undergone colon resection on the left side (L group, 92 patients) or on the right side (R group, 44 patients) . This retrospective study compared the incidence of metachronous colorectal cancer in between these groups. [Results] : Clinicopathological factors, including sex, pathological type, and disease stage, did not differ significantly between the groups. The overall survival rate for each disease stage was similar between the groups. The L group had a significantly higher rate of metachronous adenoma (p=0.022) , although the incidence of metachronous cancer was similar between the groups (p=0.898) . [Conclusion] : Resection of the terminal ileum does not increase the risk for metachronous colorectal cancer.