Intensive imaging or carcinoembryonic antigen (CEA) screening each gave an increased rate of surgical treatment of recurrence with curative intent compared with minimal follow-up for patients who had undergone curative surgery for primary colorectal cancer, according to a study published online Jan. 15 by JAMA. Combining modalities failed to provide any advantage.
Two elements of follow-up regimens for metastatic recurrence of colorectal cancer are CT of the chest, abdomen, and pelvis and regular blood CEA measurement. Both have the ability to detect isolated metastatic recurrence at an early and surgically treatable stage. John N. Primrose, MD, FRCS, of the University of Southampton in England, and colleagues assessed the effect of both procedures as follow-up to detect recurrent colorectal cancer treatable with curative intent.
Primrose and colleagues conducted a Follow-up After Colorectal Surgery (FACS) trial that was a factorial two by two pragmatic randomized clinical trial. Participants from 39 centers in the United Kingdom were involved in the study and were independently randomized to undergoing CT imaging every six to 12 months or minimum follow-up and CEA testing every three to six months of minimum follow-up. Follow-up occurred for five years after trial entry.
Findings revealed that cancer recurrence that was locoregional was detected in 199 of the 1,202 participants. Metastatic disease limited to the lung and/or liver was found in 101 of the study’s population. Three intensive interventions generally detected recurrence earlier but the differences in detection were not statistically significant. No recurrences were treatable with curative intent detected in the minimum follow-up group after the second year. The researchers found that two-thirds of the recurrences were discovered by a scheduled follow-up investigation.
Of the study’ participants, 5.9 percent experienced recurrence surgically treated with curative intent. Surgical treatment of recurrence with curative intent was found to be higher in each of the three more intensive follow-up groups than the minimum follow-up group. The odds ratio for the group that used CT and CEA together was similar to that of the groups in which the procedures were performed alone, indicating that no advantage comes from using them together. Surgical treatment of recurrence with curative intent was performed in 2.3 percent of the minimum follow-up group, 6.7 percent in the CEA group, 8 percent in the CT group, and 6.6 percent in the combined group.
“Because of the detailed investigation performed before trial entry to exclude residual disease, our results also provide data on the timing of recurrence that can strengthen the evidence base for choosing the optimal frequency of testing,” wrote the study’s authors. “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.”