Abstract
BACKGROUND: Evidence on adherence, diagnostic performance and impact on survival to intensive follow-up after surgery for colorectal cancer (CRC) is limited. AIM: To analyze the diagnostic performance of surveillance colonoscopy, computed tomography (CT), and tumor markers (TMs) in detecting CRC recurrence or metastasis during follow-up after CRC resection. Secondary objectives included degree of adherence to clinical practice guidelines surveillance recommendations and factors associated with adherence and all-cause and CRC mortality. METHODS: The single-center retrospective cohort study including patients undergoing curative resection of stage I-III CRC during 2010-2015. Follow-up was performed using TMs every 6 months, yearly CT for 5 years, and colonoscopy at years 1 and 4. Demographic, primary tumor data, and results at follow-up were collected. RESULTS: Of 574 included patients included, 153 had recurrences or metastases. Of this group, 136 (88.9%) were diagnosed by CT, 10 (6.5%) by CT and colonoscopy, and 7 (4.6%) by colonoscopy; only 67.8% showed TMs elevation. Adherence to follow-up recommendations was 68.8% for the first colonoscopy, 74% for the first CT scan, and 96.6% for the first blood test; these values declined over time. Younger age at diagnosis [odds ratio (OR) 0.93; 95%CI: 0.91-0.95], CRC stages I-II (OR 0.38; 95%CI: 0.24-0.61), and adherence to follow-up recommendations (OR 0.30; 95%CI: 0.20-0.46) were independently associated with lower risk for all-cause death at 5 years. CONCLUSION: CT scan had the highest diagnostic yield. Adherence to follow-up recommendations was low and decreased during follow-up. Younger age at diagnosis, stage, and follow-up adherence were associated with lower 5-year mortality.