Is preoperative PET/CT necessary for advanced colon cancer?

PET/CT prior to hepatic resection for advanced colorectal cancer patients with liver metastases may not be as beneficial as previously thought, according to a study published today in the Journal of the American Medicine Association.

It was once thought that it would behoove patients with colon cancer advanced to the point of liver metastasis to have a PET/CT scan to help determine the best route for surgery and to prevent unnecessarily invasive treatments if they would be noncurative. In a turn, clinical trial co-investigator Steven Gallinger, MD, head of the hepatobiliary/pancreatic surgical oncology program at University Health Network and Mount Sinai Hospital, and professor of surgery at the University of Toronto, landed on less than overwhelming results that raise questions about PET/CT’s benefit in this case.  

“To our knowledge, our study is the largest, based on high-quality imaging and reading of scans, to understand the role of PET/CT in selecting the best colorectal cancer candidates whose cancer has spread to the liver for surgery,” said Gallinger in a statement. “We did not anticipate that PET/CT would have such a small impact on hepatic surgery in our patients.”

For this study, the team evaluated PET/CT in patients with advanced colon cancer with liver metastases and compared the results with patients who had not undergone PET/CT imaging prior to surgery to see the effect of imaging on surgery management, patient survival and any potential link between standardized uptake value and survival.

A total of 263 patients were assessed for this randomized trial conducted between 2005 and 2013 at nine hospitals and five academic institutions across Ontario. Results showed that 21 of the patients who had undergone PET/CT prior to surgery had a change in surgical management, or about 8 percent. Of these, 7 patients went on to have more extensive liver resection and 9 needed surgery for additional organ involvement.

About 91 percent of patients who underwent PET/CT went on to have liver surgery, similarly to the 92 percent of the controls who also had surgery. Fatality rate after 36 months for the PET/CT group was 11.13 events per 1000 person-months. For the control group, it was 12.71.

“Among patients with potentially resectable hepatic metastases of colorectal adenocarcinoma, the use of PET-CT compared with CT alone did not result in frequent change in surgical management,” wrote the authors. “These findings raise questions about the value of PET-CT scans in this setting.”