The PSA > 4.0 will prompt a DRE (you are right about this) and a follow up PSA likely within the next 6 months. This level of PSA could be due to BPH more commonly than prostate cancer but prostate cancer does begin to become a concern. I've seen such levels return to more normal levels on follow up at times but I've also seen cases such as yours later be confirmed as prostate cancer. You will likely have at least one follow up PSA level and a DRE before the decision is made to biopsy. The decision to biopsy would depend on these next results both of the DRE and repeat PSA. A continued rise in the PSA would probably prompt the recommendation to biopsy.
I hope this information helps. Further questions are welcome if you have others. If my answer has been helpful and to your satisfaction then please remember to press the "ACCEPT" button. Thank You and Best Regards,
Anthony Bray MD