Synchronous colorectal cancers: a review of clinical features, diagnosis, treatment, and prognosis.

BACKGROUND/AIMS With the development of early diagnostic technologies, more synchronous colorectal cancers (SCRCs) can be clinically detected. Although SCRCs are recognized as a significant clinical entity, their clinical features, diagnosis, treatment, and prognosis have yet to be definitively established. In order to obtain a comprehensive understanding of this disease and to establish an efficient profile by which to recognize individuals at high risk of developing SCRCs, we carried out a review of the relevant literature. METHODS The PubMed database was searched for publications of 'synchronous colorectal carcinoma/cancer/adenocarcinoma' and 'multiple colorectal carcinomas'. All publications up to January 2011 were considered, and then only articles in English were retrieved for inclusion in this review. RESULTS The incidence of SCRCs was found to be higher in older and male patients. The prognosis in patients with SCRCs was equivalent to that in patients with solitary CRC. The failure to diagnose synchronous lesions before and during the operation was associated with repeated surgery. CONCLUSION SCRCs possess distinctive features compared to solitary CRC. While all colorectal patients should be carefully assessed to rule out the presence of concurrent colon adenomas, since missed lesions can result in additional surgery and poor prognosis, particular attention should be given to the high-risk group of older male patients.