PET-CT Passes Test in Head and Neck Cancer

In up to 40% of patients with advanced head and neck cancer, chemotherapy and radiotherapy don't eliminate the cancer from the lymph nodes. A recently reported study in The New England Journal of Medicine shows that using PET-CT to check for this persistent cancer can spare many patients from surgery—without reducing their odds of survival.

The standard adjunct to treatment for advanced head and neck cancer has been surgery to remove neck lymph nodes in case they carry residual disease. Doctors have been shifting toward a different strategy that involves operating only if PET-CT shows that cancer remains in the lymph nodes. However, evidence supporting the switch came largely from results of small single-center studies, and unequivocal data from large randomized prospective trials have been lacking.

To determine whether the two approaches are equally effective, Hisham Mehanna, MD, PhD, of the University of Birmingham in the United Kingdom, and colleagues randomly assigned 564 patients, all of whom had advanced head and neck cancer and were treated at one of 37 head and neck treatment centers in the United Kingdom, to either of two groups. One group had neck surgery to remove lymph nodes either before or after they finished chemotherapy and radiotherapy. The other had PET-CT 12 weeks after completing chemotherapy and radiotherapy. Patients in the second group had surgery only if imaging showed residual cancer in the lymph nodes or if the results were equivocal. In the end, 54 of the 282 patients in PET-CT group had surgery.

After monitoring nearly all of the patients for 2 years, and some for up to 5 years, the researchers detected no difference in survival. They found that 84.9% of the patients in the PET-CT group were still alive after 2 years, versus 81.5% in the surgery group. “The worry was that if PET-CT was not good enough, you'd be missing people with cancer in the neck,” says Mehanna. “We found that it didn't do that. It was as good as a neck dissection.”

PET-CT's effectiveness didn't depend on whether patients had been infected with the human papillomavirus (HPV), a leading cause of head and neck cancer. Seventy-five percent of patients had HPV-positive tumors, and their odds of survival were the same as those of patients with HPV-negative tumors.

Mehanna and colleagues identified two advantages to PET-CT. About 80% of the patients in the PET-CT group avoided surgery—and its potential complications. The other benefit was the cost, which was $2,190 less per patient for PET-CT surveillance, the researchers reported.

One issue that still needs to be resolved, says Mehanna, is the best follow-up for patients whose PET-CT results are equivocal. In the study, these individuals underwent surgery, but that may not be necessary for patients with HPV-positive disease, because residual cancer might be absent from their lymph nodes. Researchers need more data to find out whether these patients are as likely to survive if they forgo surgery, he says.

“People are moving away from planned neck dissections following definitive chemoradiation, and we've gotten more comfortable with monitoring patients using PET-CT,” says Jennifer Grandis, MD, of the University of California, San Francisco, who wasn't connected to the research. “This study is reassuring that PET-CT is a reasonable approach to monitor disease activity.” –Mitch Leslie