VALUE OF POSTOPERATIVE SURVEILLANCE AFTER RADICAL SURGERY FOR COLORECTAL-CANCER - RESULTS OF A COHORT STUDY

PURPOSE: Early detection of recurrence after curative resection for pr imary colorectal cancer should improve patients' prognosis. However, t he usefulness of postoperative surveillance programs has not been clar ified yet. The present cohort study was aimed at assessing the effecti veness of systematic follow-up in patients with colorectal cancer who were operated on for cure, regarding both rate of tumor recurrence ame nable to curative-intent surgery and rate of survival. METHODS: One hu ndred ninety-nine colorectal cancer patients who underwent radical pri mary surgery were followed according a well-defined postoperative surv eillance program, which consisted of laboratory studies (including ser um carcinoembryonic antigen assay) every three months, physical examin ation and abdominal ultrasound or computed tomography every six months , and chest radiograph and total colonoscopy once per year. Cohorts we re defined according to patients' compliance with the proposed follow- up program. A multivariate regression model was constructed to predict survival. RESULTS: One hundred forty patients were considered to be c ompliant with the surveillance program, whereas the remaining 59 patie nts occasionally attended follow-up investigations or did not comply a t all. Although there were no differences in the overall recurrence ra te (38 vs. 41 percent; P = 0.52), curative-intent reoperation was poss ible in 18 patients (34 percent) of those with tumor recurrence in the compliant cohort but in only 3 patients (12 percent) in the noncompli ant cohort (P = 0.05). Similarly, the probability of survival was high er in the compliant cohort, both regarding overall (63 vs. 37 percent at 5 years; P < 0.001) and cancer-related (69 vs. 49 percent at 5 year s; P < 0.02) rates. Cox regression analysis disclosed that only a more advanced TNM stage (odds ratio, 8.17; 95 percent confidence interval, 1.13-59.29) and noncompliance with the postoperative surveillance pro gram (odds ratio, 2.32; 95 percent confidence interval, 1.50-3.60) had an independent negative impact on survival. CONCLUSION: Systematic po stoperative surveillance in patients with colorectal cancer who were o perated on for cure increases both the rate of tumor recurrence amenab le to curative-intent surgery and rate of survival.