prostate cancer

Prostate cancer is the uncontrolled growth of cells in the prostate, a gland in the male reproductive system just below the bladder. Early prostate cancer usually causes no symptoms. As the cancer develops, one or more tumors can damage nearby organs causing erectile dysfunction, blood in the urine or semen, and trouble urinating. For some patients, the cancer eventually spread to other areas of the body, particularly the bones and lymph nodes. There, tumors cause severe bone pain, leg weakness or paralysis, and eventually death. Most cases of prostate cancer are detected after screening tests – typically blood tests for levels of prostate-specific antigen (PSA) – indicate unusual growth of prostate tissue. A definitive diagnosis requires a biopsy of the prostate, which is examined by a pathologist under a microscope. If cancer is present, the pathologist assigns a Gleason score of 6 to 10, with higher scores representing a more dangerous cancer disease. Medical imaging is performed to look for cancer spread outside the prostate. Based on the Gleason score, PSA levels, and imaging results, a cancer case is assigned a stage 1 to 4. Higher stage signifies a more advanced, more dangerous disease. Prostate cancer is different from all other common cancers in that as many as three out of four patients have more than one primary cancer focus. The different tumor foci have different properties, including sets of somatic mutations, which complicates the diagnostics and prognostication of the disease. Most prostate tumors remain small and cause no health problems. These are managed with active surveillance, monitoring the tumor with regular tests to ensure it has not grown. Tumors more likely to be dangerous can be destroyed with radiation therapy or surgically removed by radical prostatectomy. Those whose cancer returns or has already spread beyond the prostate, are treated with hormone therapy that reduces levels of the androgens (male sex hormones) that prostate cells need in order to survive. This halts tumor growth for a while, but eventually cancer cells grow resistant to this treatment. This most-advanced stage of the disease, called castration-resistant prostate cancer, is treated with continued hormone therapy alongside the chemotherapy drug docetaxel. Prostate cancer prognosis depends on how far the cancer has spread at diagnosis and on particular biological properties of the cancer cells.