Heroin abuse plus cigarettes is a clinically proven direct cause of cancer because if your immune system is only running at 70%; as it is with heroin; you're body is no longer physically able to protect itself from cancer or if you continue to use after you are diagnosed with cancer you will never recover.

This is a possible cause of throat cancer; which I'm mentioning; because some people never tell the whole story; as in regards to the Micheal Douglas case.