Patients with certain oral cancers that contain the human papillomavirus (HPV) have better outcomes than similar patients with tumors that lack the virus, according to researchers from Ohio State University.
Their study involved 323 patients with stage III or IV oropharyngeal cancer (cancers of the upper throat) who were part of a Radiation Therapy Oncology Group clinical trial. Of these patients, 206 had HPV-positive tumors and 117 had HPV-negative tumors.
"Our findings show that HPV status is as strong a predictor of outcome as cancer stage for patients with oropharyngeal cancers, even after considering other factors such as age and smoking history," said lead author Maura Gillison, M.D., Ph.D., a medical oncologist and head and neck cancer specialist at the Ohio State University Comprehensive Cancer Center-James Cancer Hospital and Solove Research Institute. "We're still not entirely sure why this is, but these data provide further evidence that HPV-positive oropharyngeal cancer is a distinct disease entity."
Previous smaller studies by Dr. Gillison and others have suggested that oropharyngeal cancer patients with HPV-positive tumors fare better than their HPV-negative counterparts. But patients with HPV-positive oropharyngeal cancer tend to be younger and have smaller tumors at diagnosis, and they are less likely to smoke than HPV-negative patients. This is the first study large enough to consider HPV together with these other factors in patients who received the same therapy in a large clinical trial, according to the researchers.
Dr. Gillison and her colleagues compared the patients for overall survival and progression-free survival, the time it took for cancer to again progress.
After a median follow-up of 4.5 years and controlling for possible confounding factors such as therapy and smoking status, 88% of the HPV-positive patients were still alive after two years compared with 66% of HPV-negative patients. Progression-free survival for HPV-positive patients was 72% and 50% for HPV-negative patients after two years. The incidence of second primary cancers among HPV-positive patients was less than half that of HPV-negative patients: 4% versus 11%.
The findings suggest that patients with HPV-positive tumors have less than half the chance of dying from their cancers in five years compared to those with HPV-negative tumors, the researchers concluded.
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