Source: Dotmed
Author: Heather Mayer

For some time now, experts have suspected a link between the human papillomavirus and oral cancer. DOTmed News reported in April that HPV could be linked to a nearly one-quarter increase in mouth and throat cancers in the United States (see DM 12140). But now it’s been shown that not only can HPV cause oral cancer, but it can increase a patient’s chance of survival, according to a study from the Ohio State University Comprehensive Cancer Center.

The report, published last week in the New England Journal of Medicine found that the presence of HPV, the virus that causes cervical cancer, is the most important predictor of survival for people with oropharyngeal cancer — cancer of the back of the mouth.

Lifetime smoking history and cancer stage follow HPV as survival predictors.

“We believe HPV cancers are likely more susceptible to radiation treatment than tobacco tumors,” says Brian Hill, founder and executive director of the Oral Cancer Foundation and cancer survivor.

While historically, most oral cancers were caused by tobacco and alcohol, within the past couple of decades, HPV has become a key player in causing the cancer, explains Hill. He points out that the cells in the back of mouth are attractive to the virus.

Lead researcher and neck cancer specialist Dr. Maura Gillison, conducted the retrospective study, analyzing the tumors and outcomes of 323 patients with stage 3 or 4 oropharyngeal cancer. Of these patients, 206 had HPV-positive tumors, and 117 tested negative for HPV tumors.

Three years after treatment, 82 percent of patients with HPV-positive tumors were still alive, compared with 57 percent of patients with HPV-negative tumors. Cancer relapse rates at three years were 74 percent for HPV-positive and 43 percent for HPV-negative patients.

The researchers took into account smoking and found that at three years, 93 percent of patients with HPV-positive tumors who never smoked or were light smokers were alive; 70 percent of patients with HPV-positive tumors who were smokers survived; as well as 46 percent of patients with HPV-negative tumors who were smokers.

With these findings, researchers hope to be able to use a less aggressive treatment for patients with HPV-positive tumors. In some cases, advanced tumors require 72 grays of radiation, which is close to the maximum lifetime dose, says Hill. But because HPV is more susceptible to treatment, 50 or 60 grays may be effective.

Gillison says there is a clinical trial in the works to test whether it’s possible to reduce radiation dosage from 70 to 54 grays. Patient enrollment is imminent.

It’s also possible, explains Hill, that somewhere down the line, the HPV vaccine currently marketed to young women to prevent cervical cancer, could be used to prevent HPV-16, which causes oral cancer.

“We can’t say for certain this will happen, but it’s plausible,” he says.