Clinicians Question Usefulness of Multiple Post-Treatment PET/CT Scans for Head and Neck Cancer

So far, insurance reimbursement hasn’t been an issue at the University of Pittsburgh; however, Dr. Branstetter sees trouble brewing on the horizon and has heard from plenty of colleagues in other states where insurers would never permit similar protocols. Even so, he contends that such restrictions have routinely taken effect, with limited or no science to support or refute them. “I recognize that our scheme is very much reliant on where we are practicing, and that our success is reliant on that as well,” he said. “We’re taking advantage of that while we can, so we can put science in place to justify either more or less utilization than what people are using.”

The university’s surveillance also comes with important caveats. A recent study of 512 patients by Dr. Branstetter and colleagues, for example, suggests that a single negative PET/CT scan carries a negative predictive value of 91 percent for recurrence of head and neck squamous cell carcinoma, an inadequate cure rate for deferring further surveillance (Am J Neuroradiol. 2013;34:1632-1636). Two consecutive negative results, however, yielded a negative predictive value of 98 percent. After the second negative result, Dr. Branstetter said, doctors can stop all imaging surveillance unless the patient develops symptoms. “It’s powerful information, and it genuinely changes the surveillance protocols in a subset of patients,” he said.

At Johns Hopkins, Dr. Gourin said her practice group has decided not to use subgroup analysis to determine which asymptomatic patients might benefit from post-treatment surveillance imaging. Although a patient treated for a more aggressive disease such as piriform sinus cancer may be at much higher risk for recurrence and distant disease, she said, cancer persistence after treatment would likely show up on the three-month scan. And if the cancer recurs after chemotherapy or radiation, she added, finding the tumor before signs or symptoms materialize offers no advantage. “Just to routinely scan the asymptomatic and otherwise healthy patient does not make sense,” she said. “We follow them clinically.”

As in the United States, protocols vary throughout Europe, though physicians abroad generally face a higher level of scrutiny with repeated use. In France, a clinical trial of 91 patients suggested that a single scan at 12 months after treatment is highly effective in detecting recurrence, despite a false positive rate of 23 percent (J Nucl Med. 2009;50:24-29).