A lot of men die with prostate cancer, because only very few die from it. And if you belong to the former group, knowing about it or doing any kind of intervention means a massive loss in quality of life. So the best course of action overall is to close our eyes and stop looking. And hope you don't belong to the latter group.
edit: Ah ok. Risk of over-treatment by broad scanning? "Active surveillance aims to avoid unnecessary treatment of harmless cancers while still providing timely treatment for those who need it." according to NHS.