Prostate cancer is an uncontrolled (malignant) growth of cells in the prostate gland. The gland is a walnut-sized structure at the base of the bladder, wrapped around the urethra, the tube that carries urine out of the body. It is responsible for helping control urination as well as forming part of the semen. The PSA blood test is commonly done to screen men for prostate cancer and may often detect cancers before they cause any symptoms. Prostate biopsy (taking tissue samples) is used to confirm a cancer diagnosis and assess it. Prostate cancer treatment varies depending on the stage of the disease. In the early stages when the cancer has not spread, surgery and radiation therapy are options. Surgery to remove the prostate and some of the tissue around it is called radical prostatectomy. Radiation therapy uses high-powered X-rays or radioactive seed implants to kill cancer cells. Prostate cancer that has spread may be treated with drugs to reduce testosterone levels, surgery to remove the testes, or chemotherapy. Testosterone is the main male hormone, and prostate tumours need testosterone to grow. Prostate cancer is the most commonly diagnosed cancer, and the third most common cause of cancer deaths in men.