Men with more than two oral sex partners are more likely to contract HPV

Men who have had more than two oral sex partners are "significantly" more likely to contract HPV, a viral infection that can develop into oesophageal cancer, a new study has found.

HPV, or the human papillomavirus, causes about 20-25 per cent of oesophageal cancer cases, said Professor Shan Rajendra from UNSW's Ingham Institute.

Men are three times more likely than women to contract HPV through oral sex. Smoking and drinking are also big risk factors causing oesophageal cancer, reports news.com.au.

Actor Michael Douglas, who smoked and drank excessively, famously went public about the cause of his own oesophageal cancer after being diagnosed in August 2010.

"This particular cancer is caused by HPV [human papillomavirus], which actually comes about from cunnilingus." Douglas, the husband of Catherine Zeta Jones, told The Guardian in 2013. "It's a sexually transmitted disease that causes cancer."

The study was presented at the Gastroenterological Society's annual Australian Gastroenterology Week last weekend and was also published in the academic journal Diseases of the Oesophagus.

"What we found was that if you had more than two oral sex partners in your lifetime, then you increase your risk of HPV-associated esophageal cancer significantly," Professor Rajendra said.

"It's sexually transmitted. You swallow the virus and it gets absorbed by the body and gets into the lining of the oesophagus. In some people it doesn't get cleared by the immune system. In most people it gets cleared but if it doesn't get cleared it can cause cancers of the head and neck," he said.

Straight men who perform cunnilingus are three times more likely than women to contract the virus, because vaginal fluid has a higher viral load and men's bodies are less able to clear the virus, Prof Rajendra said.

Australia was the first country in the world to offer a vaccine for HPV. Introduced in 2008, it was a compulsory vaccine for teenage girls in years 11 and 12.

But the good news is the treatment success rates of oesophageal cancer are actually higher among those who contracted the disease via HPV. The prognosis is not as good for people whose throat cancer is caused by poor lifestyle choices such as smoking and drinking.

Professor Shan Rajendra's study of 142 patients with esophageal cancer found those who were "virus positive" — meaning they developed the disease through having HPV — had the earliest stage cancers and responded best to treatment.

"They were responding to surgery or endoscopic treatments so much better than those who were virus negative. They also responded better to chemotherapy and radiotherapy," he said.

"People with the virus live longer because their cancer proteins knock off the normal conventional pathway to cancer. That gives a favourable prognosis."