Effect of 3-5 years of scheduled CEA and CT follow-up to detect recurrence of colorectal cancer: FACS randomized controlled trial.

Abstract

3500 Background: Intensive long-term follow-up after surgery for colorectal cancer is common practice but neither the actual benefit nor the optimal methodology is known. Methods: Pragmatic factorial randomised controlled trial in 39 UK hospitals, comparing minimum follow-up (which included a single CT scan at 12-18 months) with 3-6 monthly blood carcinoembryonic antigen (CEA) testing and 6-12 monthly computerised tomography (CT) imaging of the chest, abdomen and pelvis following 1202 participants for 3-5 (mean 3.7) years. Results: The proportion of participants with recurrence treated surgically with curative intent was lower than predicted (6.0% overall) but was about 3x higher in the more intensive than minimum follow-up arms (p=0.019). The adjusted odds were 2.7 for CEA only (p=0.035) and 3.4 for CT only (p=0.007); the absolute differences in detection rate in the more intensive arms compared to minimum follow-up were 4.3-5.7% (5.8-8.0% per protocol). Combining CEA and CT provided no additional benefit (adjusted odds for CT+CEA arm = 2.9). The absolute difference in the proportion of participants with recurrence treated surgically with curative intent in the factorial comparison was 1.4% for CEA (p=0.28) and 2.8% for CT (p=0.04). There was no statistical difference in colorectal cancer deaths nor overall deaths in the minimum compared to the intensive follow-up arms. Conclusions: Both regular CEA measurement and CT scanning result in significantly higher rates of diagnosis of operable recurrent colorectal cancer compared to minimal follow up. There is no benefit in monitoring with both CEA and CT. To date no difference in the overall mortality has been demonstrated. CEA monitoring combined with a single CT scan at 12-18 months seems likely to be cost effective. Clinical trial information: 41458548.