I've never heard of it being done.

It is done in a small minority of cases for breast cancer.  But in those
cases, a gene has been identified which is very strongly associated with
the disease.  women who possess that gene may in some cases have
prophylactic surgery.  I don't believe there is anything similar for
prostate cancer.

If your relatives had prostate cancer after age 65, your risk may not be
specially high.   In any case, your best strategy is to have regular
examinations including PSA tests and digital rectal examination.  You
might even have this done yearly by a urologist.   You should pay
special attention to whether or not the PSA seems to be rising.  A
urologist should be able to tell if such a rise merits a biopsy.
Finally, you might discuss whether havinga free PSA test would be of any
value.

I believe that even among rational skeptics about PSA testing, it would
be agreed that you are a prime candidate for such testing.