Don't trust GI Joe--ignorance is half the battle, at least according to the US Preventative Services Taskforce. The task force recommended against screening healthy men for prostate cancer because most of the prostate cancers detected will not kill the patient, and the complications from treatment can be quite severe (impotence, loss of bladder control, etc).
Still, I find the panel's conclusion strange. Couldn't one screen for the cancer, and then just opt out of treatment? How can more information be bad?