There is an article from physicians at the Cleveland clinic in the journal of clinical oncology:
Aggressiveness of Familial Prostate Cancer

The important points for men who have a family history of prostate cancer is that the 10 year biochemical relapse-free survival were worse for patients with a family history of prostate cancer before 1992, but since then were similar.

I think that awareness and screening has helped survival in patients that probably have more aggressive forms of prostate cancer.