One isn't subject to (incontinence/impotence) from a false positive PSA. One could be subject to a biopsy from a false positive PSA, but biopsies don't lead to incontinence and impotence, and it's always the patients choice anyway not to get a biopsy.
You’re right. Sorry for the lack of clarity. I meant to say that the PSA (as opposed to the digital exam) may turn up cancer that is slow growing and may be better subjected to “watchful waiting,” rather than surgery that may lead to the aforementioned complications. Although many will want the cancer out no matter what (and I would probably be one of them) some, especially those who are well past fifty, might want a more conservative approach.