Prostate cancer- what are the best diagmostic tool- biopsi/mri/serology -psa values? What is the best treatment option? Male 64- obese- high bp

Biopsy. A biopsy should be done but if the psa is very high, > 100 unlikely anything else. A biopsy will give tissue diagnosis, grade of the tumor, and help the physician decide on therapy. Hope this helps.
Prostate ca. If there's a suspicion of prostate cancer, the first step is to do digital rectal exam and psa. If both or any of those are elevated/suspicious for a malignant tumor, the next step is biopsy. Mri doesn't play a major rôle in the diagnosis of prostate cancer. It may be used later when the diagnosis of cancer is established to check for possible spread. Treatment depends on stage/aggressiveness.