[Monitoring colorectal cancer after surgical resection]

POSTOPERATIVE FOLLOW-UP: Despite adjuvant therapy, approximately 50% of all patients undergoing curative surgery for Dukes C colorectal cancer will develop a recurrence within 3-5 years and 95% of these will die from their cancer shortly thereafter. ENDOSCOPY: Generally performed every 3 years after checking that all cancerous foci have been removed, colonoscopy is required to detect adenomes and metachronic cancers. Its contribution to screening for local recurrence is however rather limited since most recurrences develop in an extraluminal localization. CEA: Assayed at 8 months, repeated carcinoembryonic antigen assay can detect asymptomatic recurrence in 50 to 60% of the cases, usually 4 to 8 months prior to other explorations. Specificity is high (85% to 95% depending on the series), allowing exploratory laparotomy if CEA alone is elevated. However, the only randomized study evaluating CEA was unable to demonstrate any prolongation of survival with monthly tests. OPTIMAL FOLLOW-UP: There is some debate about the usefulness of intensive clinical and radiographic follow-up as the 4 randomized studies available were unable to demonstrate any beneficial effect. It must be noted however that the number of patients included in these studies was too low to evidence a small improvement in survival rates. In France, a 6% improvement at 5 years would result in 200 fewer deaths due to Duke C colorectal cancer annually. A large multicentric randomized study will be initiated shortly in France to evaluate the impact of intensive CEA monitoring versus no monitoring and intensive versus periodical radiological follow-up.