Synchronous colorectal cancer

Purpose: Synchronous colorectal cancer is clinically significant because there is a chance to miss concurrent lesions. The aim of this study is to investigate the clinical features of synchronous colorectal cancer. Methods: Retrospectively, the records of 4,494 colorectal cancer patients who underwent a potentially curative resection for colorectal cancer from September 1994 to December 2005 were reviewed. Synchronous colorectal cancer was defined according to the following two criteria: 1) two or more colorectal cancers had to be found simultaneously in the same patient and 2) each of the tumors had to be distinctly separated by an intact bowel wall. Results: Synchronous colorectal cancer was diagnosed in 114 patients (2.5%). Synchronous colorectal cancer shows different features compared with single colorectal cancer. Synchronous colorectal cancer occurs at a older age, occurs more frequently in the colon, has a bigger size, and has more polyps. There was no difference of stage based on survival rate between synchronous and single colorectal cancer patients. The preoperative diagnosis rate of synchronous colorectal cancer was 74.6%. Eleven (9.6%) synchronous colorectal cancer patients underwent a total colectomy, and there were no significant differences in survival or complications compared with the other group. Conclusion: Synchronous colorectal cancer is difficult to diagnose preoperatively. Early postoperative examination for synchronous colorectal cancer is required, especially in patients who did not have a complete preoperative evaluation.