Background: Up to 9 per cent of patients who undergo resection for colorectal cancer develop metachronous cancers. There is no consensus on the detection and management of such cancers.
Methods: The literature was reviewed exhaustively regarding the incidence, clinical characteristics, detection, treatment and molecular genetics of metachronous colorectal cancers. This was based on a Medline search from 1966 to December 1997 for articles on metachronous colorectal cancers. A manual search was also performed on references quoted in these articles. All publications relevant to this study were included.
Results: Although the underlying causes for metachronous colorectal cancers are yet to be elucidated, risk factors for the disease have been identified. These include the presence of synchronous polyps or cancers, a history of metachronous cancers, and hereditary non-polyposis colorectal cancer (HNPCC).
Conclusion: Preoperative colonoscopy and postoperative colonoscopic surveillance are essential in identifying patients at risk of metachronous colorectal cancer. A total colectomy and ileorectal anastomosis should be considered for some patients, certainly for those with HNPCC.