Prostate cancer. Coloured axial magnetic resonance imaging (MRI) scans of the lower abdomen of a 74- year-old man who has an adenocarcinoma of the prostate gland. The front of the body is at top on each scan, which is a view seen from below. The prostate gland (orange) is at the centre of each scan. It has been highlighted by the injection of a gadolinium contrast medium. The bladder (grey), partially seen above the enlarged prostate gland in the lower two scans, is being compressed by the cancer, affecting urination. The circular areas at left and right in each scan are the tops of the thigh bones. The causes of prostate cancer are not known, but it is most prevalent in men over 50 years of age. Treatment is with hormone therapy, chemotherapy, or surgery to remove the prostate gland. This advanced cancer has a Gleason score of 9. The patient has a PSA reading of 13.