Oral sex caused my throat cancer: Michael Douglas

'Basic Instinct' star Michael Douglas believes his throat cancer was triggered by oral sex.

It has been widely thought that the 68-year-old Hollywood star's years of drinking and smoking were to blame for the stage four cancer, which was first diagnosed in 2010.

Douglas said he initially thought that stress was behind his near fatal condition but now he has come to believe that HPV virus, transmitted through oral sex, was responsible for it, the Guardian reported.

Asked if he now regretted his years of smoking and drinking, he said, "No, because without wanting to get too specific, this particular cancer is caused by HPV, which actually comes about from cunnilingus.

"I did worry if the stress caused by my son's incarceration didn't help trigger it. But yeah, it's a sexually transmitted disease that causes cancer. And if you have it, cunnilingus is also the best cure for it."

Douglas, 68, who is married to Catherine Zeta Jones, and has three children, was diagnosed with cancer in August 2010, following many months of oral discomfort.

The actor embarked on an intensive eight-week course of chemotherapy and radiation. Douglas lost 20kg on a liquids-only diet while he was in treatment.

"That's a rough ride. That can really take it out of you. Plus the amount of chemo I was getting, it zaps all the good stuff too. It made me very weak."

Douglas is now more than two years clear of cancer. The actor goes for check-ups every six months and believes that this kind of cancer does not come back 90 per cent of the time".