A few thoughts to offer. It sounds as if you were given a standard systematic 12 core biopsy, which takes 12 samples from different zones of your prostate. I would think that having 2 of those cores positive with cancer indicates a fairly sizeable lesion or more than one lesion. What is your PSA? Have you had a 3T MRI. The MRI will shed much better light on the size and location of your tumor or if there is more than one lesion. A genetic test of the tumor tissue such as Decipher or Oncotype dx would shed light on how aggressive the Gleason 4 cells might be. Your urologist could and should be ordering these kinds of tests for you and advocate for yourself that they be done, if this isn't the case. This kind of additional information will go a long way in helping you make a better informed decision on what to do for your particular case.