Tumor HPV status prognostic in oropharyngeal cancer: study

NEW YORK (Reuters Health) - Tumor HPV status is a strong and independent predictor of survival for patients with stage III or IV squamous cell carcinoma of the oral cavity, pharynx or larynx, according to a study to be reported later this month at the American Society of Clinical Oncology's annual meeting in Orlando.

In the study, patients with HPV-positive tumors (mostly HPV subtype 16) had better outcomes than patients with HPV-negative tumors.

"We are still not entirely sure why this is, but there data provide further evidence that HPV-positive oropharyngeal cancer is a distinct disease entity," Dr. Maura Gillison of The Ohio State University in Columbus noted in an ASCO-issued release.

Dr. Gillison and colleagues compared the survival outcomes for 206 patients with HPV-positive oropharyngeal cancer and 117 with HPV-negative oropharyngeal cancer. All patients received a combination of radiation and chemotherapy.

"At 2 years, 88% of patients with HPV-positive tumors were alive, compared to 66% of patients with HPV-negative tumors," Dr. Gillison said during a pre-meeting press briefing. "The difference increased over time so that by 5 years the absolute difference in survival had increased to 29%."

"In a separate type of survival analysis," Dr. Gillison noted, "we were surprised to find that HPV-positive patients had less than half the risk of dying from their cancer at 5 years when compared to HPV-negative patients, even after considering the effects of six other important factors including treatment assignment."

In addition, HPV-positive patients had approximately half the risk of tumor progression or death at 5 years when compared to HPV-negative patients.

The investigators also looked at rates of second cancers given that patients with head and neck cancers are at high risk of being diagnosed with a second cancer.

They found that rates for second cancers for HPV-positive patients were significantly lower than those for HPV-negative patients. "This was largely due to dramatically reduced rates of second cancers associated with smoking, in particular oral cavity, oropharynx or other head and neck cancers, esophageal cancer and lung cancer," Dr. Gillison reported.

Tumor HPV status evaluation," she concluded, "may now be part of routine clinical care because patients will want to know about it because of its prognostic implications and in the future may impact choice of therapy."

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