CT After Colorectal Cancer Surgery Offers Only Small Advantages

Patients who have undergone curative surgery for primary colorectal cancer who receive follow-up with CT and blood tests may go on to have more surgery - but their survival advantage is small, according to an article published in the JAMA.

Researchers from the University of Southampton and the University of Oxford in the U.K. sought to assess the effect of scheduled blood carcinoembryonic antigen (CEA) and CT as follow-up to detect recurrent colorectal cancer treatable with curative intent. Currently, such follow-up is based on limited evidence.

A total of 1,202 patients who had undergone curative surgery for primary colorectal cancer were recruited between January 2003 and August 2009. The patients may also have undergone adjuvant treatment.

The patients were randomly assigned to one of four groups: CEA only (300 patients), CT only (299 patients), both CEA and CT (302 patients), and minimal follow-up (301 patients). Blood CEA was measured every three months for two years, then every six months for three years. Patients who underwent CT had scans of the chest, abdomen, and pelvis every six months for two years, then annually for three years. The patients in the minimum follow-up group only received follow-up if symptoms occurred.

The results showed that after a mean 4.4 years of observation, cancer recurrence was detected in 199 participants (16.6 percent) overall. Of the total 1,202 participants, 71 (5.9 percent) were treated for recurrence with curative intent, with little difference according to Dukes staging (stage A, 5.1 percent [13/254]; stage B, 6.1 percent [34/553]; stage C, 6.2 percent [22/354]). Seven of the 301 patients (2.3 percent) in the minimum follow-up group underwent surgical treatment of recurrence with curative intent, as did 20 of 300 (6.7 percent) in the CEA group, 24 of 299 (8 percent) in the CT group, and 20 of 302 (6.6 percent) in the CEA plus CT group.

“Compared with minimum follow-up, the absolute difference in the percentage of patients treated with curative intent in the CEA group was 4.4 percent (95 percent CI, 1.0 percent to 7.9 percent; adjusted odds ratio [OR], 3.00; 95 percent CI, 1.23 to 7.33), in the CT group was 5.7 percent (95 percent CI, 2.2 percent to 9.5 percent; adjusted OR, 3.63; 95 percent CI, 1.51 to 8.69), and in the CEA+CT group was 4.3 percent (95 percent CI, 1.0 percent to 7.9 percent; adjusted OR, 3.10; 95 percent CI, 1.10-8.71),” the authors wrote. “The number of deaths was not significantly different in the combined intensive monitoring groups (CEA, CT, and CEA+CT; 18.2 percent [164/901]) versus the minimum follow-up group (15.9 percent [48/301]; difference, 2.3 percent; 95 percent CI, −2.6 percent to 7.1 percent).”

The researchers concluded that survival advantage to any of these follow-up strategies were likely to be small.