Wylde is correct about prostate CA. By the time a man is in his 60's, there is usually some microscopic evidence of it, and by the 70's almost all men have some small sections of the gland that harbor cancer cells. The malignant cells usually remain well encapsulated, and as Wylde reported, most men die of something else before some physiologic change "lets the dogs out". The question is what makes some men prone to early malignant changes AND why does the encapsulating mechanism fail?
In the meanwhile, take good care of your prostate: have at least 2-3 orgasms a week to keep the plumbing flushed out.