Mostly there is no needing for testing for existed tumors at the prostate
you should exam the PSA or Prostate specific Anti-gen this gen is found on the blood and done with the normal blood test from your vein(same with liver enzymes, testosterone etc.)
as long as this gen is low then you're away from prostate cancer or even diseases but if it increased then you're in a big risk, doesn't mean that you have a tumor but you'll get tumor in the following few months or years if you didn't do anything regard it