Poison Drummer Rikki Rockett: I Have Cancer ... Michael Douglas Was Right

Rikki Rockett is fighting oral cancer, and says it was caused by HPV ... the same way Michael Douglas got it.

Poison's drummer was on the Sirius XM show "Eddie Trunk Live" when he revealed his diagnosis, saying it all started over the summer when he had a cold and a sore throat. He says doctors at USC eventually did a biopsy and discovered a tumor at the base of his tongue.

Rikki says the human papillomavirus is behind his diagnosis -- "This is very similar to [Iron Maiden's] Bruce Dickinson, very similar to Michael Douglas, similar to [Aerosmith's] Tom Hamilton, as far as I know."

Been a rough year for Rikki -- as we first reported, he filed to divorce his wife Melanie in July.

The good news -- 54-year-old Rikki says he's been responding well to treatment and his prognosis is "excellent."