Most prostate cancers are first found during screening with a PSA blood test and/or a digital rectal exam (DRE). Early prostate cancers usually don’t cause symptoms, but more advanced forms may be found because of symptoms they cause. Whether prostate cancer is suspected based on screening tests or the presence of symptoms, the actual diagnosis is made with a biopsy of the prostate.
A pathologist studies prostate tissue samples collected during a biopsy under a microscope to determine the grade of the tumor (i.e., how different the tumor tissue is from normal prostate tissue).
Sometimes primary cancer is discovered only after the metastatic tumor begins to cause symptoms. For example, if your prostate cancer has spread to the bones in your pelvis, you may have lower back pain. Although not common, this may happen before you experience any symptoms from the primary tumor in your prostate.