The damage is cumulative. So yes, it is quite likely that her cancer had to do with her smoking. It is the same reason that doctors strongly recommend sunscreen for young children. Not for the skin cancers they will develop the next day, but to prevent the skin cancers they will develop in 30 years due to the radiation damage.Strangely enough, I agree. I had a rather eye opening event about this. A dear friend died of breast cancer a few years ago, and she had been a smoker but had quit smoking about 20 years before her cancer appeared. Her death was attributed to smoking even though there was no evidence that it had any contribution to her cancer but the policy is to that if you smoked and you get cancer (and probably other illnesses) your cause of death is due to smoking.