Prostate cancer • How it works? Researched 12 times

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«Prostate cancer is the development of cancer in the prostate, a gland in the male reproductive system.^[6] Most prostate cancer are slow growing; however, some grow relatively quickly.^[1]^[3] The cancer cell may spread from the prostate to other areas of the body, particularly the bone and lymph nodes.^[7] It may initially cause no symptoms.^[1] In later stages, it can lead to difficulty urinating, blood in the urine or pain in the pelvis, back, or when urinating.^[2] A disease known as benign prostatic hyperplasia may produce similar symptoms.^[1] Other late symptoms may include feeling tired due to low levels of red blood cell.^[1]

Factors that increase the risk of prostate cancer include older age, a family history of the disease, and race.^[3] About 99% of cases occur in males over the age of 50.^[3] Having a first-degree relative with the disease increases the risk two to threefold.^[3] In the United States, it is more common in the African American population than the White American population.^[3] Other factors that may be involved include a diet high in processed meat, red meat or milk products or low in certain vegetables.^[3] An association with gonorrhea has been found, but a reason for this relationship has not been identified.^[8] An increased risk is associated with the BRCA mutations.^[9] Prostate cancer is diagnosed by biopsy.^[2]Medical imaging may then be done to determine if the cancer has spread to other parts of the body.^[2]

Prostate cancer screening is controversial.^[3]^[10]Prostate-specific antigen (PSA) testing increases cancer detection, but it is controversial regarding whether it improves outcomes.^[10]^[11]^[12] Informed decision making is recommended when it comes to screening among those 55 to 69 years old.^[13]^[14] Testing, if carried out, is more reasonable in those with a longer life expectancy.^[15] 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.^[3] Supplementation with vitamins or minerals does not appear to affect the risk.^[3]^[16]

Many cases are managed with active surveillance or watchful waiting.^[2] Other treatments may include a combination of surgery, radiation therapy, hormone therapy or chemotherapy.^[2] When it only occurs inside the prostate, it may be curable.^[1] In those in whom the disease has spread to the bone, pain medications, bisphosphonate and targeted therapy, among others, may be useful.^[2] Outcomes depend on a person's age and other health problems as well as how aggressive and extensive the cancer is.^[2] Most men with prostate cancer do not end up dying from the disease.^[2] The 5-year survival rate in the United States is 99%.^[4] Globally, it is the second most common type of cancer and the fifth leading cause of cancer-related death in men.^[5] In 2012, it occurred in 1.1 million men and caused 307,000 deaths.^[5] It was the most common cancer in males in 84 countries,^[3] occurring more commonly in the developed world.^[17] Rates have been increasing in the developing world.^[17] Detection increased significantly in the 1980s and 1990s in many areas due to increased PSA testing.^[3] Studies of males who died from unrelated causes have found prostate cancer in 30% to 70% of those over age 60.^[1]

Early prostate cancer usually has no clear symptoms. Sometimes 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.^[18]

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.^[18]

Metastatic prostate cancer that has spread to other parts of the body can cause additional symptoms. The most common symptom is bone pain, often in the vertebrae (bone of the spine), pelvis, or ribs. Spread of cancer into other bone 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.^[19]

A complete understanding of the causes of prostate cancer remains elusive.^[20] The primary risk factors are obesity, age, and family history. Prostate cancer is very uncommon in men younger than 45, but becomes more common with advancing age. The average age at the time of diagnosis is 70.^[21] Many men never know they have prostate cancer. Autopsy studies of Chinese, German, Israeli, Jamaican, Swedish, and Ugandan men who died of other causes have found prostate cancer in 30% of men in their fifties, and in 80% of men in their seventies.^[22] Men who have first-degree family members with prostate cancer appear to have double the risk of getting the disease compared to men without prostate cancer in the family.^[23] This risk appears to be greater for men with an affected brother than for men with an affected father. In the United States in 2005, there were an estimated 230,000 new cases of prostate cancer and 30,000 deaths due to prostate cancer.^[24] Men with high blood pressure are more likely to develop prostate cancer.^[25] There is a small increased risk of prostate cancer associated with lack of exercise.^[26] A 2010 study found that prostate basal cell were the most common site of origin for prostate cancer.^[27]

Genetic background may contribute to prostate cancer risk, as suggested by associations with race, family, and specific gene variants. Men who have a first-degree relative (father or brother) with prostate cancer have twice the risk of developing prostate cancer, and those with two first-degree relatives affected have a fivefold greater risk compared with men with no family history.^[28] In the United States, prostate cancer more commonly affects black men than white or Hispanic men, and is also more deadly in black men.^[29]^[30] In contrast, the incidence and mortality rates for Hispanic men are one third lower than for non-Hispanic whites. Studies of twins in Scandinavia suggest that 40% of prostate cancer risk can be explained by inherited factors.^[31]

No single gene is responsible for prostate cancer; many different genes have been implicated. Mutations in BRCA1 and BRCA2, important risk factors for ovarian cancer and breast cancer in women, have also been implicated in prostate cancer.^[32] Other linked genes include the Hereditary Prostate cancer gene 1 (HPC1), the androgen receptor, and the vitamin D receptor.^[29]TMPRSS2-ETS gene familyfusion, specifically TMPRSS2-ERG or TMPRSS2-ETV1/4 promotes cancer cell growth.^[33] These fusions can arise via complex rearrangement chains called chromoplexy.^[34]

Two large genome-wide association studies linking single-nucleotide polymorphisms (SNPs) to prostate cancer were published in 2008.^[35]^[36] These studies identified several SNPs which substantially affect the risk of prostate cancer. For example, individuals with TT allele pair at SNP rs10993994 were reported to be at 1.6 times higher risk of prostate cancer than those with the CC allele pair. This SNP explains part of the increased prostate cancer risk of African American men as compared to American men of European descent, since the C allele is much more prevalent in the latter; this SNP is located in the promoter region of the MSMB gene, thus affects the amount of MSMB protein synthesized and secreted by epithelial cell of the prostate.^[37]

Finally, obesity^[38] and elevated blood levels of testosterone^[39] may increase the risk for prostate cancer.» (wikipedia)