Colorectal cancer follow-up: a reassessment of empirical evidence on effectiveness

Colorectal cancer is an important cause of death in the Western world, with a propensity of cancer recurrence even after resection with curative intent. Active follow-up has been advocated as a means to detect cancer recurrence at an earlier stage and thereby improve the survival of colorectal cancer patients. The present study assesses published evidence on the effectiveness of follow-up. Articles were obtained from a 20-year Medline search and from cross-references between articles. Articles were included, scored for quality, and extracted by explicit criteria. Regression analysis and chi-squared analysis was performed to assess (1) whether detection of recurrence at earlier asymptomatic disease stage leads to better post-treatment prognosis, and (2) whether active follow-up does improve overall (quality adjusted) survival, as compared to symptom-guided care only. The relationship between disease stage of recurrence (symptoms, number and size) and survival was analysed from 42 articles, 10 of which provided adequate data. Absence of symptoms and small number of recurrence were significantly related to better survival, smaller size insignificantly so. The potential of active follow-up seemed related to a marginally better outcome, larger gains being found in lower quality studies. Available data do suggest that survival gains vary between 0.5 and 2%, 1% seeming to be a best estimate of overall survival gain. Neither the notion that earlier detection of recurrences does significantly improve outcome, nor the hope that active follow-up provides a statistically and clinically significant gain in (quality adjusted) survival, are so far supported by adequate evidence. Colorectal cancer follow-up still fails to meet the criteria for evidence based medicine.