The number of oral cancer cases in the UK has for the first time surged past 6,000 incidences a year, according to a report released on Friday. 

Cancer Research UK said that ten years ago the oral cancer rate was just over 4,400 cases of oral cancer a year compared to the latest figures of 6,200, with two thirds of the cases in men.

While experts attribute most cases to smoking and excessive alcohol use, they believe another main factor contributing to the spike in mouth cancer rates may be infections from the human papillomavirus (HPV) that commonly spreads through oral sex.

Experts believe up to 80 percent of the UK population has at some point in their lives been infected with HPV, although most cases are harmless, high-risks strains of the virus are not only linked to oral cancers, but also cervical and other genital cancers.

HPV infections are usually on the fingers, hands, mouth and genitals and experts say that most people will never even know they’ve had the virus. Only a few strains are considered high-risk because they can lead to cell changes which could develop into cancer, especially the notorious HPV-16 strain. 

“We have seen a rapid increase in the number of HPV16-positive cases of oral cancer. We have also noticed that patients with HPV-related oral cancers tend to be younger, are less likely to be smokers and have better outcomes from treatment than those whose tumors show no evidence of HPV,” Richard Shaw, a Cancer Research UK expert in head and neck cancers, based at the Liverpool Cancer Research UK Center, said in a statement released on Friday.

Researchers said that there were two particularly sharp rises in the incidence rates of two specific types of oral cancers that have been linked to HPV: cancer tumors at the base of the tongue rose by almost 90 percent from 284 to 595, and a 70 percent rise in tonsil cancers from 573 to 1,052 over a decade.

“This raises questions as to exactly how these cancers develop and why they only affect a small proportion of people who are exposed,” Shaw said noting that HPV-related cancers appeared to behave differently than other oral cancers not related to the virus.

Experts said that oral cancer has traditionally been associated with risk factors like tobacco and alcohol, and oral cancers tend to take at least a decade to develop, so by examining lifestyles 20 to 30 years ago can help researchers understand the reason behind the rise in cases.

Smoking rates in the UK have halved over the last three decades, but while there was a seven percent increase in the amount of alcohol bought in the UK over the last two decades, experts believe alcohol consumption alone cannot fully explain the recent spike in oral cancer rates. 

“It’s worrying to see such a big rise in oral cancer rates. But like many other cancers, if oral cancer is caught early, there is a better chance of successful treatment,” Sara Hiom, director of information at Cancer Research UK said in a statement.  “So it’s really important for people to know the signs and symptoms of oral cancer - mainly mouth ulcers that just won’t heal, any lumps or thickening in the mouth, lips or throat, or red or white patches in the mouth that won’t go away.”

Doctors as well as dentists all play a significant part in spotting oral cancer, and health care providers should all encourage their patients to take care of their mouths and attend regular dental checkups, Hiom added.