The fear of having prostate cancer can be devastating to men. However, it is most successfully treated when found early. Consider these statistics from the American Cancer Society (ACS):
- More than 90 percent of all prostate cancers are discovered while they are either localized (confined to the prostate) or regional (nearby). The five-year survival rate for men diagnosed with prostate tumors discovered at these stages is nearly 100 percent.
- In the past 25 years, the five-year survival rate for all stages combined has increased from 68 to nearly 100 percent.
- Prostate cancer is the most common cancer among men, excluding skin cancer.
- For 2012, the ACS estimates 241,740 new cases of prostate cancer will be diagnosed in the U.S.
- Year 2012 estimates also include 28,170 deaths occurring from prostate cancer in the U.S. alone, making it the second leading cause of cancer death in men.
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The prostate is a sex gland in men. It is about the size of a walnut, although it can grow larger, and surrounds the neck of the bladder and urethra—the tube that carries urine from the bladder. It is partly muscular and partly glandular, with ducts opening into the prostatic portion of the urethra. It is made up of three lobes: a center lobe with one lobe on each side.
The prostate gland secretes a slightly alkaline fluid that forms part of the seminal fluid, a fluid that carries sperm.
There are usually no specific signs or symptoms of early prostate cancer. A prostate-specific antigen (PSA) blood test and digital rectal exam (DRE) can provide the best chance of identifying prostate cancer in its earliest stages, but these tests can have drawbacks. Talk to your doctor about whether prostate cancer screening is right for you.
The following are the most common symptoms of prostate cancer. However, each individual may experience symptoms differently. Symptoms may include:
- Weak or interrupted flow of urine
- Urinating often (especially at night)
- Difficulty urinating or holding back urine
- Inability to urinate
- Pain or burning when urinating
- Blood in the urine or semen
- Nagging pain in the back, hips, or pelvis because cancer has spread to the bones
- Painful ejaculation
The symptoms of prostate cancer may resemble other conditions or medical problems. Always consult your doctor for a diagnosis.
As a man gets older, his prostate may grow bigger and obstruct the flow of urine, or interfere with sexual function. An enlarged prostate gland—a condition called benign prostate hyperplasia— may require treatment with medicine or surgery to relieve symptoms. This common benign prostate condition, which is not cancer, can cause many of the same symptoms as prostate cancer.
In general, all men are at risk for prostate cancer. However, there are specific risk factors that increase the likelihood that certain men will develop the disease, including the following:
- Age. Age is a risk factor for prostate cancer, especially for men 50 and older. Nearly two-thirds of all prostate cancers are diagnosed in men over the age of 65.
- Race. Prostate cancer is more common among African-American men than it is among white American men. Japanese and Chinese men native to their country have the lowest rates of prostate cancer. Interestingly, when Chinese and Japanese men immigrate to the U.S., they have an increased risk of and mortality rate from prostate cancer, when compared to their native populations. In Japan, the incidence of prostate cancer has increased as Western diets and lifestyles have been adopted.
- Diet. Epidemiological data suggest that the diet consumed in Western industrialized countries may be a factor in developing prostate cancer. Consider the following information regarding diet and its effect on the risk for prostate cancer:
- Fat. Some studies suggest that men who eat a high-fat diet, especially if it is high in red meat or high-fat dairy products, may have a greater chance of developing prostate cancer.
- Fruits and vegetables. Diets high in fruits and vegetables may lower prostate cancer risk, although it is not clear which nutrient(s) may be responsible for this.
- Vitamin E and selenium. Vitamin E, an antioxidant, combined with selenium, has been shown to inhibit tumor growth in laboratory animals. But a large study found that supplements of these substances did not lower the risk of prostate cancer in men. In fact, the men taking vitamin E had a slightly higher risk of prostate cancer.
- Carotenoids. Carotenoids such as lycopenes have been shown to inhibit the growth of human prostate cancer cells in tissue cultures (cells grown in the laboratory). The primary source of lycopenes is processed tomatoes. Again, however, it is not clear if lycopenes affect prostate cancer risk in men, as not all studies have found a benefit.
- Obesity. Most studies have not found obesity to affect the risk of getting prostate cancer, but obese men may be more likely to develop more aggressive forms of prostate cancer.
- Environmental exposures. Some studies show an increased risk of prostate cancer in men who are farmers, or those exposed to the metal cadmium while making batteries, welding, or electroplating. Additional research is needed in this area to confirm whether this is a true association.
- Having a vasectomy, BPH (benign prostatic hyperplasia), or an STD (sexually transmitted disease). Researchers have looked at whether men who have had a vasectomy, BPH, or those who have been exposed to a sexually transmitted disease are at increased risk for prostate cancer. Some studies suggest a link, while others do not support these claims.
- Family history of prostate cancer. Having a father or brother with prostate cancer more than doubles a man's risk of developing this disease. The risk is even higher for men with several affected relatives, particularly if the relatives were young at the time of diagnosis. Geneticists (doctors and scientists who study inheritance and the causes of genetic disease) divide families into three groups, depending on the number of men with prostate cancer and their ages of onset, including the following:
- Sporadic. A family with prostate cancer present in one man, at a typical age of onset; sporadic means occurs by chance.
- Familial. A family with prostate cancer present in more than one person, but with no definitive pattern of inheritance and usually an older age of onset.
- Hereditary. A family with a cluster of three or more affected relatives within any nuclear family (parents and their children), a family with prostate cancer in each of three generations on either the mother or father's side, or a cluster of two relatives affected at a young age (55 or younger). Five to 10 percent of prostate cancer cases are considered hereditary.
- Genetic factors. In the center of each cell of the human body, our genetic material—chromosomes—are found. Normally, cells contain 46 chromosomes, or 23 pairs, half of which are inherited from our mother, half from our father. The chromosomes contain genes, the body's blueprint. Genes code for traits, such as eye color and blood type, and also control important regulatory functions in the body, such as the rate of cell growth. Some genes, when altered or mutated, give a higher risk for uncontrolled cell growth, which, in turn, can lead to tumor development. These genes have various names, but overall are referred to as cancer susceptibility genes. Approximately five to 10 percent of all prostate cancers are known to be attributed to an inherited DNA change, such as the cancer susceptibility gene.
In addition to regular physical examinations that may include blood, urine, and possibly other laboratory tests, many groups, such as the American Cancer Society, suggest talking to your doctor to learn more about the pros and cons of screening for prostate cancer to help you decide if it is right for you. Other expert groups have different recommendations. For example, the U.S. Preventive Services Task Force recommends against routine prostate cancer screening because the task force believes the benefit does not outweigh the harm. The tests used for screening include:
- DRE (digital rectal examinations). The doctor places a gloved and lubricated finger into the rectum to examine the rectum and feel the prostate gland. DREs may be conducted annually for men over the age of 50 who choose to be screened. Men in high-risk groups, such as African-Americans, or those with a strong family history of prostate cancer, should consult their doctors about being tested at age 45.
- PSA (prostate-specific antigen). PSA is a substance produced by the prostate gland, which may be found in higher amounts in the blood of men who have prostate cancer. PSA tests may be done annually for men over the age of 50 who choose to be tested. Men in high-risk groups, such as African Americans, or those with a strong family history of prostate cancer, should consult their doctors about being tested at an earlier age.
If the DRE or PSA results are unusual, your doctor may repeat the tests or request other procedures. These evaluation tools may include:
- Prostate biopsy. A test where the doctor inserts thin, hollow needles into the prostate to get samples for examination under a mircoscope to determine if cancer cells are present.
- Transrectal ultrasound (TRUS). A test using sound wave echoes to create an image of the prostate gland to visually inspect for abnormal conditions such as gland enlargement, nodules, penetration of tumor through capsule of the gland, and/or invasion of seminal vesicles; may also be used for guidance of needle biopsies of the prostate gland and/or guiding the nitrogen probes in cryosurgery.
- Computed tomography scan (also called a CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
- Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
- Radionuclide bone scan. A nuclear imaging method that helps to show whether the cancer has spread from the prostate gland to the bones. The procedure involves an injection of radioactive material that helps to locate diseased bone cells throughout the entire body, suggesting possible metastatic cancer.
- Lymph node biopsy. A procedure in which tissue samples are removed (with a needle or during surgery) from the lymph nodes for examination under a microscope; to determine if cancer or other abnormal cells are present.
The diagnosis of cancer is confirmed only by a biopsy.
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