ASCO Saturday 1^st June 2013 – Dr Nick Maisey

Following a curative operation to remove bowel cancer, relapses can occur and if they do, tend to happen between 2 to 3 years post-op. There has long been controversy about how best we should monitor patients after their initial operation. Does regular CT scanning increase our chance of detecting a relapse which might be removable if caught early, or does it just add extra radiation exposure to our patients?

Carcinoembryonic antigen (CEA) is a blood test that is used to monitor the activity of bowel cancer in patients with metastatic disease. What is the role of this blood test in monitoring for a recurrence? In the first presentation in the colorectal session on Saturday, a team from Oxford University led by Professor Mant (abstract 3500), presented the results of their clinical trial. Over 1000 patients whose primary cancer had been removed and where there was no evidence of secondaries, were randomised to be followed up according to one of four possible strategies. One group had minimal follow-up, consisting of a single CT scan between 12 to 18 months post-operation and any other tests only if new symptoms developed. The second group had regular CEA blood tests (3 monthly for 2 years, then 6 monthly for 3 years) as well as the single CT scan. The third group had regular CT scans (6 monthly for 2 years, then yearly for 3 years). Finally the fourth group had the most intense follow-up with a combination of regular blood tests and CT scans. The study was designed to compare how successful each strategy was in picking up early recurrences that were amenable to a second curative operation.

The results of this showed that there was a three times better chance of detecting an early treatable recurrence in the more intensive groups compared to the minimal approach. Interestingly there did not appear to be any difference between the three intensive strategies.

These results suggest that we need to be vigilant in our follow-up programmes, but that intensive blood testing with a single follow-up CT may be adequate and so we may be able to limit our patients exposure to unnecessary radiation.