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THURSDAY, Feb. 20, 2014 (HealthDay News) -- Patients with recurrent mouth and throat cancers are more likely to survive if the tumors are caused by the human papillomavirus (HPV) and not smoking, according to new research.
"Until this study, we thought that once these cancers came back, patients did equally poorly regardless of whether their disease was linked to HPV," said study leader Dr. Carole Fakhry, an assistant professor in the department of otolaryngology at the Johns Hopkins University School of Medicine.
"Now we know that once they recur, HPV status still matters," Fakhry said in a university news release. "They still do better."
The study included nearly 200 patients with late-stage mouth or throat cancer who had undergone successful chemotherapy and radiation treatment. Of those patients, 58 percent had cancers caused by HPV and 42 percent had cancers triggered by smoking or other causes.
The median time between the end of treatment and the reappearance of cancer was similar -- a little more than eight months for those with HPV-positive cancers and about seven months for those with HPV-negative cancers.
But about 55 percent of patients with HPV-positive cancers were alive two years after recurrence, compared with 28 percent of those with HPV-negative cancers, according to the study.
The researchers also found that patients whose recurrent cancer could be treated with surgery -- regardless of whether it was HPV-related or not -- were 52 percent less likely to die than those who did not have surgery.
The study was scheduled for presentation Thursday at the Multidisciplinary Head and Neck Cancer Symposium in Scottsdale, Ariz.
"Historically, if you had a recurrence, you might as well get your affairs in order, because survival rates were so dismal," Fakhry said. "It was hard to say, 'Yes, you should go through surgery.'"
"But this study shows us that surgery may have a significant survival benefit, particularly in HPV-positive patients," she said.
It's not clear why patients with HPV-related mouth and throat cancers are more likely to survive than those with HPV-negative cancers, the researchers said, but it might be that HPV-related cancers are less aggressive or respond better to chemotherapy or radiation treatment.
Throat and mouth cancers were once linked primarily to heavy smoking. Now they are more often caused by HPV, a sexually transmitted virus. About 70 percent of mouth and throat cancers in the United States are HPV-positive, according to the study.
Data and conclusions presented at meetings typically are considered preliminary until published in a peer-reviewed medical journal.
The U.S. National Cancer Institute has more about oral cancer.