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Prostate cancer, also known as carcinoma of the prostate, is the development of cancer in the prostate, a gland in the male reproductive system.〔(【引用サイトリンク】url=http://www.cancer.gov/cancertopics/types/prostate )〕 Most prostate cancers are slow growing; however, some grow relatively quickly.〔 The cancer cells may spread from the prostate to other parts of the body, particularly the bones and lymph nodes. It may initially cause no symptoms.〔 In later stages it can lead to difficulty urinating, blood in the urine, or pain in the pelvis, back or when urinating. A disease known as benign prostatic hyperplasia may produce similar symptoms. Other late symptoms may include feeling tired due to low levels of red blood cells.〔 Factors that increase the risk of prostate cancer include: older age, a family history of the disease, and race. About 99% of cases occur in those over the age of 50. Having a first degree relative with the disease increases the risk 2 to 3 fold. In the United States it is more common in the African American population than the White American population. Other factors that may be involved include a diet high in processed meat, red meat, or milk products or low in certain vegetables.〔 An association with gonorrhea has been found, but a reason for this relationship has not been identified. Prostate cancer is diagnosed by biopsy. Medical imaging may then be done to determine if the cancer has spread to other parts of the body.〔 Prostate cancer screening is controversial.〔〔 Prostate-specific antigen (PSA) testing increases cancer detection but does not decrease mortality. The United States Preventive Services Task Force recommends against screening using the PSA testing, due to the risk of over-diagnosis and over-treatment as most cancer diagnosed would remain asymptomatic. The USPSTF concludes that the potential benefits of testing do not outweigh the expected harms. While 5α-reductase inhibitors appear to decrease low grade cancer risk they do not affect high grade cancer risk and thus are not recommended for prevention.〔 Supplementation with vitamins or minerals does not appear to affect the risk.〔 Many cases can be safely followed with active surveillance or watchful waiting. Other treatments may include a combination of surgery, radiation therapy, hormone therapy or chemotherapy.〔 When it only occurs inside the prostate it may be curable. In those in whom the disease has spread to the bones, pain medications, bisphosphonates and targeted therapy, among others, may be useful. Outcomes depend on a person's age and other health problems as well as how aggressive and extensive the cancer is. Most people with prostate cancer do not end up dying from the disease.〔 The five year survival rate in the United States is 99%.〔(【引用サイトリンク】url=http://seer.cancer.gov/statfacts/html/prost.html )〕 Globally it is the second most common type of cancer and the fifth leading cause of cancer-related death in men. In 2012 it occurred in 1.1 million men and caused 307,000 deaths.〔 It was the most common cancer in males in 84 countries,〔 occurring more commonly in the developed world. Rates have been increasing in the developing world. Detection increased significantly in the 1980s and 1990s in many areas due to increased PSA testing.〔 Studies of males who died from unrelated causes have found prostate cancer in 30% to 70% of those over age 60.〔 ==Signs and symptoms== Early prostate cancer usually has no clear symptoms. Sometimes, however, prostate cancer does cause symptoms, often similar to those of diseases such as benign prostatic hyperplasia. These include frequent urination, nocturia (increased urination at night), difficulty starting and maintaining a steady stream of urine, hematuria (blood in the urine), and dysuria (painful urination). A study based on the 1998 Patient Care Evaluation in the US found that about a third of patients diagnosed with prostate cancer had one or more such symptoms, while two thirds had no symptoms.〔 Prostate cancer is associated with urinary dysfunction as the prostate gland surrounds the prostatic urethra. Changes within the gland, therefore, directly affect urinary function. Because the ''vas deferens'' deposits seminal fluid into the prostatic urethra, and secretions from the prostate gland itself are included in semen content, prostate cancer may also cause problems with sexual function and performance, such as difficulty achieving erection or painful ejaculation. Advanced prostate cancer can spread to other parts of the body, possibly causing additional symptoms. The most common symptom is bone pain, often in the vertebrae (bones of the spine), pelvis, or ribs. Spread of cancer into other bones such as the femur is usually to the proximal or nearby part of the bone. Prostate cancer in the spine can also compress the spinal cord, causing tingling, leg weakness and urinary and fecal incontinence. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「prostate cancer」の詳細全文を読む スポンサード リンク
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