CR30P
METACHRONOUS COLORECTAL CANCER

Purpose:   The purpose of this article is to review the current knowledge relating to risk factors, tumorigenesis and survival of patients with metachronous colorectal cancer to address potential advances in surveillance and management of patients with colorectal cancer.Methodology:   The Cochrane Library, PubMed, EMBASE and Ovid databases were searched from 1966 to December 2008 for both published reviews and published articles on metachronous colorectal cancer regarding incidence, carcinoma sequence, clinical characteristics, risk factors, detection, treatment, surveillance and survival. Further articles were obtained by a manual review of the reference lists of all retrieved articles. All publications relevant to this study were included.Results:   Factors likely to increase the risk of developing metachronous colorectal cancer include; age, personal and family history of multiple malignancies, synchronous polyps, hereditary non‐polyposis colorectal cancer and microsatellite instability.Conclusion:   Pre‐operative colonoscopic polyp status and biopsy analysis regarding microsatellite instability are essential in identifying patients at risk of metachronous colorectal cancer. A rapid adenoma‐carcinoma sequence less than the accepted 2 to 5 years would warrant stringent colonoscopic surveillance. Thus, frequent colonoscopic surveillance is recommended, within the first 5 years post‐operatively, for the detection of metachronous colorectal cancer.