The main function of the prostate is to produce semen, the milky fluid that transports sperm. Sperm is produced in the testicles, which also produce the main male hormone testosterone. Testosterone stimulates the growth and function of the prostate during puberty, as well as the production of prostatic fluid for semen.
During sexual climax (orgasm), the muscles of the prostate contract to push the semen through the urethra and out through the penis. The urethra also carries urine, a waste product made by the kidneys and stored in the bladder. When the penis is erect during sexual intercourse, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.
The prostate is located directly beneath the bladder and in front of the rectum. Because the upper portion of the urethra passes through the prostate, if the gland becomes enlarged it can obstruct the passage of urine or semen through the urethra.
Prostate cancer is the most common cancer in men, and the second leading cause of cancer death among men in the U.S. More than 180,000 men in the U.S. will be diagnosed with prostate cancer this year, and more than 40,000 will die of the disease. Eighty percent of men who reach age 80 have prostate cancer.
Prostate cancer is a malignant tumor that usually begins in the outer part of the prostate. In most men, the cancer grows very slowly. In fact, many men with the disease will never know they had the condition. Early prostate cancer is confined to the prostate gland itself, and the majority of patients with this type of cancer can live for years with no problems.
Prostate cancer is characterized by both “grade” and “stage.” The size and extent of the tumor determine its stage. Early stage prostate cancer, Stages T1 and T2, are limited to the prostate gland. Stage T3 prostate cancer has advanced to tissue immediately outside the gland. Stage T4 prostate cancer has spread to other parts of the body.
Like many cancers, the cause of prostate cancer is unknown. But doctors do know that it is more common in African-American men and men with a family history of the disease. The male sex hormone testosterone also contributes to its growth.
Prostate cancer, by nature, is silent in its initial stages. Its symptoms don’t appear until later, when patients may notice a need to urinate frequently, particularly at night. Prostate cancer may also cause a difficulty or inability to urinate, a weak or interrupted flow of urine or painful and burning urination. Other symptoms may include painful ejaculation, blood in urine or semen, and frequent pain or stiffness in the lower back, hips or extremities.
The number of cases of prostate cancer has declined among white American men. The incidence of the disease in black men and the mortality rate among black men is more than twice that of white men, according to the American Cancer Society.
The following are some of the risk factors for prostate cancer:
The PSA test is believed to detect most prostate cancers. PSA is a protein secreted by the prostate into the bloodstream. Elevated levels of this antigen may indicate the presence of prostate cancer.
If cancer is suspected, a prostate biopsy (removal of tiny pieces of prostate tissue) will be performed. By removing a tissue sample from the tumor and examining it, doctors can confirm or rule out a diagnosis of cancer and determine whether the disease has spread to other organs.
Fortunately, most prostate cancers have not spread at the time they are diagnosed, and the cancer is most often confined to the prostate gland.
To help predict the aggressiveness of the prostate cancer, your physician will look at your PSA levels before the biopsy and will also calculate the “Gleason Score.” The Gleason Score is a sum of the grades of the two most common prostate tumors. After looking at microscopic sections of the biopsied prostate tissue, the pathologist assigns a grade (from 3 to 5, with 3 being closest to normal appearance and 5 being least normal) to the tumors based on their appearance. The Gleason Score is therefore a score that ranges from 6 to 10, with 6 representing the least aggressive form (confined to the gland) and 10 representing the most aggressive form of cancer (highest risk of spreading outside the gland).
From the PSA levels and the Gleason Score, a treatment plan is devised. For men with a low risk of the cancer having spread outside the gland, staging studies such as bone scans and computed tomography scans are not needed. Men with cancer with a higher likelihood of spreading may require these staging studies to determine where the cancer may have spread.
Physicians tailor prostate cancer treatment plans to their patient’s needs, taking into account the type of cancer, the age of the individual, the degree to which the cancer has spread and the general health of the patient.
Eighty-nine percent of the men diagnosed with prostate cancer will survive at least 5 years, while 63% will survive 10 years or longer.
Because prostate cancer is a slow-growing disease, many affected men will die from other causes. Evidence also indicates that many patients detect their prostate cancer, at a curable stage, because of annual screening.
© Copyright 1995-2018 The Cleveland Clinic Foundation. All rights reserved.
This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition.
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