Many, perhaps even most, men develop prostate cancer as they age. Most of those cases don't need any treatment. In almost all men with low risk prostate cancer I recommend surveillance (no active treatment - only repeat PSA tests, rectal exams, and repeat biopsies at 1 and 3 years which is still not anything most men want to do) as opposed to radiation or prostatectomy.

But many men get super worried and want treatment anyway. So you can have a true positive result with a PSA test, get surgery or radiation (or worse cryotherapy or high energy ultrasound) to treat that cancer and develop ED or incontinence even though you never really needed any treatment at all.

I'm not all in on no PSA tests like the government task force suggests but I certainly understand their reasoning.