For patients with potentially resectable hepatic metastases of colorectal adenocarcinoma, the use of positron emission tomography with computed tomography (PET-CT) compared with CT alone did not result in frequent changes in surgical management of those patients, which raises questions about the value of using PET-CT scans in this setting. That was the conclusion of a study in the May 14 issue of the Journal of the American Medical Association (2014;311:1863-1869).
The study included 400 patients with colorectal cancer who had resectable colorectal liver metastases based on contrast-enhanced CT scans of the chest, abdomen, and pelvis within the previous 30 days, who had had a clear colonoscopy within the previous 18 months. A total of 263 patients were randomly assigned to receive PET-CT scans after the initial staging CT scan (the other patients served as the control group and had CT scans only).
Of the patients receiving PET-CT, 111 of those scans provided new information: 62 patients had liver metastases as seen on the CT, but not on the PET scan, and 49 had abnormal (37 patients) or suspicious (12) lesions as interpreted by the PET-CT reader.
Twenty-two patients had positive PET-CT scans, which on further investigation or follow-up were determined not to be cancer.
A change in surgical management as a result of the PET-CT scans occurred for 23 patients (8.7 percent of the cases): to either have no surgery (9 patients), more extensive surgery (4 patients), further nonhepatic surgery including biopsy (9 patients), or more extensive and further nonhepatic surgery (1 patient).
Liver resection was performed on 91 percent of patients in the PET-CT group and 92 percent of the patients in the control group.
The study's corresponding author, Mark Levine, MD, MSc, FRCPC, Professor and Chair of the Department of Oncology and the Buffett-Taylor Chair in Breast Cancer Research at McMaster University, noted in an email that this is the largest, prospective, randomized clinical trial to address this question of the value of PET scans for these patients. "We need to use what resources we have wisely," he said. "The benefit from doing a PET was very modest, and the funds could be used elsewhere."
Asked for his opinion for this article, Alan P. Venook, MD, the Madden Family Distinguished Professor of Medical Oncology and Translational Research at the University of California, San Francisco-who recently wrote about the management of patients with metastatic colon cancer for OT (3/25/14 issue), agreed: "I do not believe that PET-CT adds in making decisions throughout the treatment cycles, because of false-negatives from the effects of chemotherapy-making it questionable even with patients going to resection," he said via email. "The findings [from this trial] support my views."
Levine noted that he and his colleagues are now working on a formal cost-effectiveness analysis of the findings. "This is an RCT which should influence health policy," he said.