The prostate is a walnut-sized gland located between the bladder and the urethra that produces seminal fluid to protect sperm. Adenocarcinoma of the prostate is the most common form accounting for more than 95 percent of men who are diagnosed with prostate cancer. Abnormal cells slowly progress to become a malignant tumor, often located in the outer part of the prostate. Cancerous tumors can eventually metastasize, or spread beyond the prostate -- a sign of advanced disease. By the age of 50, 1 out of 4 men will have some cancerous cells in his prostate. At age 80, the ratio becomes 1 in 2. However, most men outlive their diagnosis.
WHAT ARE THE SYMPTOMS?
Prostate cancer develops slowly and may cause few, if any, symptoms. If symptoms appear, they may include:
CAUSES AND RISK FACTORS
- Difficulty or an inability to urinate, or pain or burning while urinating;
- Blood in urine;
- Painful ejaculation;
- Loss of appetite and weight; and/or
- Continual lower back, pelvic, or upper thigh pain.
It isn't entirely known what causes prostate cancer. Some prostate cancers may be inherited and caused by DNA mutations. Others may be related to hormones, environment, or diet.
Risk factors include:
- Age: The older a man is, the higher his risk of prostate cancer.
- Race: African-American men have higher incidences of the disease than American men of other ethnicities. Asian-American men have the lowest rates.
- Family history: Rates increase if a person's father or brother has the disease.
- Diet: Some researchers have linked a high-fat diet to prostate cancer. Others have found that eating too many calories (regardless of the food source) raises risk.
Prostate cancer is diagnosed through a biopsy, or the extraction of prostate tissue with a needle. However, biopsies are not performed on all men. They are indicated if a man has:
- An elevated PSA (prostate specific antigen);
- A significant change between one PSA test and the next; and
- An abnormal digital rectal examination (described below).
PSA is a blood test that detects the amount of a protein made by the prostate in the blood that is associated with prostate cancer. Experts recommend annual PSA tests for men starting at age 50 (or at age 40 if any of his close relatives have had prostate cancer). African-American men should get annual PSA tests starting at age 45.
An elevated PSA level does not always indicate cancer. Therefore, to determine the need for a biopsy, physicians may also run the following tests:
- Free PSA: This test measures the percentage of free PSA (PSA that is not bound to other molecules) in the blood. A low percentage of free PSA indicates a greater risk of having prostate cancer.
- PSA velocity: PSA velocity is the annual rate at which the PSA increases. This increase is monitored by physician.
- Digital rectal exam: In this test, which is recommended annually, the physician inserts a finger in the rectum to probe the prostate gland. Abnormally firm areas may be associated with cancer. Digital rectal exams complement PSA tests because each exam detects cancers that the other does not.
- PSA density: Physicians divide the PSA number by the prostate volume to assess the likelihood of cancer.
Certain imaging tests help assess the spread of the disease.
- Transrectal ultrasonography: (A hand-held probe inserted in the rectum that emits sound waves, which are reflected off tissues and analyzed by a computer.)
- Magnetic resonance imaging (MRI)
- Bone scan
- Computed tomography (CT) scans
Treatment for men with prostate cancer depends on:
- The man's age and life expectancy;
- His feelings about the side effects associated with each treatment;
- The grade and stage of the cancer; and
- Other health conditions.
The active treatments for prostate cancer include:
- Surgery, or removing cancer;
- Radiation, or using high-dose x rays or other forms of energy to kill cancer cells;
- Freezing cancer cells (cryotherapy);
- Hormones, which can slow or stop cancer growth; and
- Chemotherapy, or using drugs to kill cancer cells.