The Prostate

The prostate is part of a man's reproductive system. It is located in front of the rectum and under the bladder. It surrounds the urethra, the tube through which urine flows. A healthy prostate is about the size of a walnut. The prostate makes part of seminal fluid. During ejaculation, seminal fluid helps carry sperm out of the man's body as part of semen. Male hormones (androgens) make the prostate grow. The testicles are the main source of male hormones, including testosterone. The adrenal gland also makes testosterone, but in small amounts. If the prostate grows too large, it squeezes the urethra. This may slow or stop the flow of urine from the bladder to the penis.

 

 

Risk Factors

No one knows the exact causes of prostate cancer. Doctors often cannot explain why one man develops prostate cancer and another does not. However, we do know that prostate cancer is not contagious. You cannot "catch" it from another person.

Research has shown that men with certain risk factors are more likely than others to develop prostate cancer. A risk factor is something that may increase the chance of developing a disease.

Studies have found the following risk factors for prostate cancer:

• Age: Age is the main risk factor for prostate cancer. This disease is rare in men younger than 45. The chance of getting it goes up sharply as a man gets older. In the United States, most men with prostate cancer are older than 65.
• Family history: A man's risk is higher if his father or brother had prostate cancer.
• Race: Prostate cancer is more common in African American men than in white men, including Hispanic white men. It is less common in Asian and American Indian men.
• Certain prostate changes: Men with cells called high-grade prostatic intraepithelial neoplasia (PIN) may be at increased risk for prostate cancer. These prostate cells look abnormal under a microscope.
• Diet: Some studies suggest that men who eat a diet high in animal fat or meat may be at increased risk for prostate cancer. Men who eat a diet rich in fruits and vegetables may have a lower risk.

Many of these risk factors can be avoided. Others, such as family history, cannot be avoided. You can help protect yourself by staying away from known risk factors whenever possible.

Scientists have also studied whether BPH, obesity, smoking, a virus passed through sex, or lack of exercise might increase the risk for prostate cancer. At this time, these are not clear risk factors. Also, most studies have not found an increased risk of prostate cancer for men who have had a vasectomy. A vasectomy is surgery to cut or tie off the tubes that carry sperm out of the testicles.

Most men who have known risk factors do not get prostate cancer. On the other hand, men who do get the disease often have no known risk factors, except for growing older.

If you think you may be at risk, you should talk with your doctor. Your doctor may be able to suggest ways to reduce your risk and can plan a schedule for checkups.

 

Screening

Your doctor can check you for prostate cancer before you have any symptoms. Screening can help doctors find and treat cancer early. But studies so far have not shown that screening tests reduce the number of deaths from prostate cancer. You may want to talk with your doctor about the possible benefits and harms of being screened. The decision to be screened, like many other medical decisions, is a personal one. You should decide after learning the pros and cons of screening.

Your doctor can explain more about these tests:

• Digital rectal exam: The doctor inserts a lubricated, gloved finger into the rectum and feels the prostate through the rectal wall. The prostate is checked for hard or lumpy areas.
• Blood test for prostate-specific antigen (PSA): A lab checks the level of PSA in a man's blood sample. A high PSA level is commonly caused by BPH or prostatitis (inflammation of the prostate). Prostate cancer may also cause a high PSA level.

The digital rectal exam and PSA test can detect a problem in the prostate. They cannot show whether the problem is cancer or a less serious condition. Your doctor will use the results of these tests to help decide whether to check further for signs of cancer.

 

Symptoms

A man with prostate cancer may not have any symptoms. For men who have symptoms of prostate cancer, common symptoms include:

• Urinary problems
• Not being able to urinate
• Having a hard time starting or stopping the urine flow
• Needing to urinate often, especially at night
• Weak flow of urine
• Urine flow that starts and stops
• Pain or burning during urination
• Difficulty having an erection
• Blood in the urine or semen
• Frequent pain in the lower back, hips, or upper thighs

Most often, these symptoms are not due to cancer. BPH, an infection, or another health problem may cause them. Any man with these symptoms should tell his doctor so that problems can be diagnosed and treated as early as possible. He may see his regular doctor or a urologist. A urologist is a doctor whose specialty is diseases of the urinary system.

 

Diagnosis

If you have a symptom or test result that suggests cancer, your doctor must find out whether it is due to cancer or to some other cause. Your doctor will ask about your personal and family medical history. You will have a physical exam. You may have lab tests. Your visit may include a digital rectal exam, a urine test to check for blood or infection, and a blood test to measure PSA level.

You also may have other exams:

• Transrectal ultrasound: The doctor inserts a probe into the man's rectum to check for abnormal areas. The probe sends out sound waves that people cannot hear (ultrasound). The waves bounce off the prostate. A computer uses the echoes to create a picture called a sonogram.
• Cystoscopy: The doctor uses a thin, lighted tube to look into the urethra and bladder.
• Transrectal biopsy: A biopsy is the removal of tissue to look for cancer cells. It is the only sure way to diagnose prostate cancer. The doctor inserts a needle through the rectum into the prostate. The doctor takes small tissue samples from many areas of the prostate. Ultrasound may be used to guide the needle. A pathologist checks for cancer cells in the tissue.

If Cancer Is Not Found

If the physical exam and test results do not suggest cancer, your doctor may suggest medicine to reduce symptoms caused by an enlarged prostate. Surgery also can relieve these symptoms. The surgery most often used in such cases is transurethral resection of the prostate (TURP or TUR). In TURP, an instrument is inserted through the urethra to remove prostate tissue that is pressing against the upper part of the urethra and restricting the flow of urine. You should talk to your doctor about the best treatment option.

If Cancer Is Found

If cancer is present, the pathologist studies tissue samples from the prostate under a microscope to report the grade of the tumor. The grade tells how much the tumor tissue differs from normal prostate tissue. It suggests how fast the tumor is likely to grow. Tumors with higher grades tend to grow faster than those with lower grades. They are also more likely to spread.

One system of grading prostate cancer uses G1 through G4. Another way of grading is with the Gleason score. The pathologist gives each area of cancer a grade of 1 through 5. The pathologist adds the two most common grades together to make a Gleason score. Or the pathologist may add the most common grade and the highest (most abnormal) grade to get the score. Gleason scores can range from 2 to 10.

 

Staging

To plan your treatment, your doctor needs to know the extent (stage) of the disease. The stage is based on the size of the tumor, whether the cancer has spread outside the prostate and, if so, where it has spread.

You may have blood tests to see if the cancer has spread. Some men also may need imaging tests:

• Bone scan: The doctor injects a small amount of a radioactive substance into a blood vessel. It travels through the bloodstream and collects in the bones. A machine called a scanner detects and measures the radiation. The scanner makes pictures of the bones on a computer screen or on film. The pictures may show cancer that has spread to the bones.
• CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of areas inside your body. Doctors often use CT scans to see the pelvis or abdomen.
• MRI: A strong magnet linked to a computer is used to make detailed pictures of areas inside your body.

These are the stages of prostate cancer:

• Stage I: The cancer cannot be felt during a digital rectal exam. It is found by chance when surgery is done for another reason, usually for BPH. The cancer is only in the prostate.
• Stage II: The cancer is more advanced, but it has not spread outside the prostate.
• Stage III: The cancer has spread outside the prostate. It may be in the seminal vesicles. It has not spread to the lymph nodes.
• Stage IV: The cancer may be in nearby muscles and organs (beyond the seminal vesicles). It may have spread to the lymph nodes. It may have spread to other parts of the body.
• Recurrent cancer is cancer that has come back (recurred) after a time when it could not be detected. It may recur in or near the prostate. Or it may recur in any other part of the body, such as the bones.

Treatment to follow in another article.