Prostate cancer

Prostate cancer is the uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Early prostate cancer causes no symptoms. Most cases are detected after screening tests – typically blood tests for levels of prostate-specific antigen (PSA) – indicate unusual growth of prostate tissue. Diagnosis requires a biopsy of the prostate. If cancer is present, the pathologist assigns a Gleason score, with a higher score representing a more dangerous tumor. Medical imaging is performed to look for cancer that has 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.

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 spreads beyond the prostate are treated with hormone therapy that reduces levels of the androgens (male sex hormones) that prostate cells need to survive. 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. Some tumors 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.

Prostate cancer prognosis depends on how far the cancer has spread at diagnosis. Most men are diagnosed with tumors confined to the prostate; 99% of them survive more than 10 years from their diagnoses. Tumors that have metastasized to distant body sites are most dangerous, with five-year survival rates of 30–40%.

The risk of developing prostate cancer increases with age; the average age of diagnosis is 67. Those with a family history of prostate cancer are more likely to have prostate cancer. Each year 1.2 million cases of prostate cancer are diagnosed, and 350,000 die of the disease, making it the second-leading cause of cancer and cancer death in men. One in eight men is diagnosed with prostate cancer in his lifetime and one in forty dies of the disease. Prostate tumors were initially thought to be rare and an 1893 report described just 50 cases in the medical literature. As surgery became more common, prostate tumors were found in surgical specimens from enlarged prostates. Surgery and radiation treatments were developed over the course of the 20th century. Major work describing prostate tumors' need for male sex hormones, and the subsequent development of hormone therapies for prostate cancer, earned Charles B. Huggins the 1966 Nobel Prize in Physiology or Medicine, and Andrzej W. Schally the 1977 Nobel Prize in Physiology or Medicine.