Prolonged surveillance of colorectal cancer patients after curative surgeries beyond five years of follow-up.

Background: Local or distant recurrence may develop beyond 5 years after radical resection for colorectal cancer (CRC). There is little evidence of a pattern of recurrence after the routinely recommended 5 years of follow-up. We aimed to investigate the efficacy of the prolonged follow-up beyond 5 years.
Methods: We retrospectively analyzed clinical and survival data of 1,054 CRC patients who underwent radical resections from 1980 to 1996 in our center. The prolonged surveillance was recommended for each patient with a duration of over 20 years.
Results: The follow-up rates of 5, 10, 15, and 20 years were 92.6%, 86.9%, 82.3% and 76.8%, respectively. Overall survival (OS) rates of 5, 10, 15, and 20 years were 68.4%, 57.7%, 52.6% and 45.0%, respectively. Totally, 112 (10.6%) patients developed local recurrences and 174 (16.5%) patients developed distant metastases. The 99.2% postoperative local recurrences and distant metastases occurred within the first 15 years of surveillance. Survival differed between four age groups. Local recurrence was mainly diagnosed among rectal cancer patients, especially in those with lower-third rectal cancer. Metastases were commonly found in the liver and lungs. Patients with colon cancer and stage I/II manifested significantly longer OS than patients with rectal cancer and stage III/IV (both P<0.001).
Conclusions: In this study, postoperative local recurrences and distant metastases was rarely found after 15 years of enhanced surveillance, which indicated a "true cure" if the patient did not develop recurrences and metastases after 15 years.
Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.
(2019 Annals of Translational Medicine. All rights reserved.)