Additional Imaging Prior to Cancer Surgery May Not Be Warranted

Among patients with a specific type of colorectal cancer with limited metastasis to the liver, imaging using positron emission tomography (PET) and computed tomography (CT) before surgery did not significantly change the surgical treatment of the cancer, compared with just using CT scanning.

The findings were published May 13, 2014, in the Journal of the American Medical Association (JAMA). Colorectal cancer is a leading cause of cancer death. About 50% of patients present with or subsequently develop cancer that has spread to the liver. Some patients with liver metastases are candidates for surgery to have the cancer removed. However, unidentified occult metastases at the time of surgery can render the operation noncurative. Therefore, long-term survival after surgical resection (removal) for colorectal cancer liver metastases is only approximately 50%. PET-CT imaging technology could help avoid noncurative surgery by identifying patients with occult metastases, according to the researchers.


Carol-Anne Moulton, MB, BS, from the University Health Network (Toronto, Canada), and colleagues randomly ascribed patients with colorectal cancer treated by surgery with resectable metastases based on CT scans to PET-CT (n = 270) or CT only (n = 134) to determine the effect on the surgical treatment of these patients. The study, conducted between 2005 and 2013, involved 21 surgeons at nine hospitals in Ontario.

Of the 263 patients who received PET-CT scans, 111 provided new data: 62 were categorized as negative and 49 had abnormal or suspicious lesions. Change in management (canceled, more extensive liver surgery, or surgery performed on additional organs) as a result of the PET-CT findings occurred in 8.7% of patients; 2.7% avoided noncurative liver surgery. Overall, liver resection was performed on 91% of patients in the PET-CT group and 92% of the control group.

The median follow-up was three years. The researchers discovered no substantial disparity in survival or disease-free survival between patients in the PET-CT group vs. the control group. “Many countries struggle to maintain quality healthcare within existing budgets. This is difficult because of increasing healthcare costs as a result of an aging population and the expense of new therapies and technologies, including diagnostic and functional imaging,” the authors wrote in their article. “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. These findings raise questions about the value of PET-CT scans in this setting.”

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