Intensive CT imaging or blood screening after colorectal cancer surgery provided a small but increased rate of surgical treatment of recurrence with curative intent when compared with minimal follow-up, a study found.
Scheduled blood measurement of carcinoembryonic antigen (CEA) or CT as follow-up to detect recurrent colorectal cancer both provided an advantage, but there was no advantage in combining them, researchers noted.
Study authors conducted a clinical trial among 39 National Health Service hospitals in the United Kingdom among more than 1,200 eligible participants from January 2003 to August 2009 who had undergone curative surgery for primary colorectal cancer, including adjuvant treatment if indicated, and with no evidence of residual disease.
Participants were randomized among 4 groups: CEA only (n = 300), CT only (n = 299), CEA and CT (n = 302), or minimum follow-up (n = 301). Follow-up testing regimens included blood CEA every 3 months for 2 years, then every 6 months for 3 years, and/or CT scans of the chest, abdomen and pelvis every 6 months for 2 years, then annually for 3 years. The minimum follow-up group received no scheduled follow-up except a single CT scan of the chest, abdomen and pelvis at 12 to 18 months if the hospital clinicians requested it at the start of the study.
Results appeared in the Jan. 15 issue of JAMA Internal Medicine.
After a mean 4.4 (SD, 0.8) years of observation, cancer recurrence was detected in 199 participants (16.6%; 95% CI, 14.5% to 18.7%); 41 (3.4%) had locoregional recurrence and 101 (8.4%) had metastatic disease limited to the lung and/or liver.
In the study, 71 of 1,202 participants (5.9%; 95% CI, 4.6% to 7.2%) were treated for recurrence with curative intent, with little difference when broken down by Dukes staging (stage A, 5.1% [13/254]; stage B, 6.1% [34/553]; stage C, 6.2% [22/354]). Surgical treatment of recurrence with curative intent was higher in each of the 3 more intensive follow-up groups compared with the minimum follow-up group: 2.3% (7/301) in the minimum follow-up group compared to 6.7% (20/300) in the CEA group, 8% (24/299) in the CT group, and 6.6% (20/302) in the CEA and 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% (95% CI, 1.0% to 7.9%; adjusted odds ratio [OR], 3.00; 95% CI, 1.23 to 7.33), in the CT group was 5.7% (95% CI, 2.2% to 9.5%; adjusted OR, 3.63; 95% CI, 1.51 to 8.69), and in the CEA and CT group was 4.3% (95% CI, 1.0% to 7.9%; adjusted OR, 3.10; 95% CI, 1.10 to 8.71). The number of deaths was not significantly different in the 3 combined intensive monitoring groups (18.2% [164/901]) compared to the minimum follow-up group (15.9% [48/301]; difference, 2.3%; 95% CI, −2.6% to 7.1%).
Researchers noted that:
• between 12 and 20 patients need to be followed up to identify 1 potentially curable recurrence;
• CEA combined with a single CT scan at 12 to 18 months is not significantly different from CT scanning;
• because CEA testing can be done in primary care, it is likely to be more cost-effective;
• imaging is still necessary to confirm recurrence; and
• in the combined CEA and CT group, two-thirds of recurrences were first detected by CT.
Researchers concluded, “Duplication of monitoring tests does not appear to add value; participants in the CEA groups had a single CT at 12 to 18 months, when 3 recurrences were detected, but otherwise there was no suggestion of benefit from monitoring with both CEA and CT.”