Objective: To determine the most effective, evidence-based, postoperative surveillance strategy for the detection of recurrent colon and rectal cancer. Tests are to be recommended only if they have an impact on the outcomes listed below.

Potential intervention: All tests described in the literature for postoperative monitoring were considered. In addition, the data were critically evaluated to determine the optimal frequency of monitoring.

Outcomes: Outcomes of interest included overall and disease-free survival, quality of life, toxicity reduction, and cost-effectiveness. The American Society of Clinical Oncology (ASCO) Colorectal Cancer Surveillance Expert Panel was guided by the principle of cost minimization, ie, when two strategies were believed to be equally effective, the least expensive test was recommended.

Evidence: A complete MEDLINE search was performed of the past 20 years of the medical literature. Keywords included colorectal cancer, follow-up, and carcinoembryonic antigen, as well as the names of the specific tests. The search was broadened by articles from the tumor marker ASCO panel literature search, as well as from bibliographies of selected articles.

Values: Levels of evidence and guideline grades were rated by a standard process. More weight was given to studies that tested a hypothesis directly relating testing to one of the primary outcomes in a randomized design. BENEFITS/HARMS/COSTS: The possible consequences of false-positive and false-negative tests were considered in evaluating a preference for one of two tests that provide similar information. Cost alone was not a determining factor.

Recommendations: The expert panel's recommended postoperative monitoring schema is discussed in this article.

Validation: Five outside reviewers, the ASCO Health Services Research Committee, and the ASCO Board of Directors examined this document.

Sponsor: American Society of Clinical Oncology.