Screening for Prostate Cancer

Screening maximizes the chances of finding cancer while its curable. According to the American Cancer Society (ACS), 80% of prostate cancers are found while still in the localized and regional stages. The 5-year relative survival rate for patients in whom prostate cancer is found in these stages is 100%.

Prostate cancer screening methods have been hotly debated and challenged. The difficulty is that there is no direct way to assess the health of the prostate gland. In addition, prostate cancer is a very slow developing cancer, which means it can go undetected and show no symptoms for months. It is important to talk with your doctor to decide how best to screen for prostate cancer based on your personal medical and family history.

National Guidelines

Prostate cancer screening tests look for disease even though a person may have no symptoms. Currently, the ACS and the American Urological Association (AUA) recommend specific tests at specific intervals for the early detection of prostate cancer in men who do not have symptoms. Beginning at age 50, the prostate-specific antigen (PSA) blood test and the Digital Rectal Exam (DRE) should be offered yearly to men who are expected to live at least 10 more years. The ACS and AUA also recommend that men at high risk for prostate cancer (including African American men and men with a first-degree relative, such as a father or brother, who was diagnosed with prostate cancer at a young age) begin testing at age 45.

Digital Rectal Exam (DRE)

The DRE can be performed during a regular office visit. Men are asked to bend forward over a table, kneel, or lay on one side. A gloved and lubricated finger is inserted into the rectum to feel the sides and back of the prostate gland to check its size, firmness, and texture. The provider feels for any abnormal hardened areas or lumps. This exam is brief, usually lasting less than a minute, and generally not painful, though a bit uncomfortable.

Since not all of the prostate can be felt during the DRE and a very small lump may be missed, it is frequently coupled with the PSA blood test.

The Prostate-Specific Antigen (PSA) Test

The PSA screening test is a blood test that looks for a specific tumor marker. In general, tumor markers are produced by the tumor itself or by our body in response to the presence of cancer or non-cancerous conditions. If a tumor marker level is higher than normal, the patient is examined more closely to look for cancer or other conditions. The most commonly tested tumor marker for the prostate gland is prostate specific antigen. It is normally present in low levels in the blood of all adult men. The normal range is 0 to 4 ng/ml.

PSA is prostate-specific, not cancer-specific. A variety of conditions can raise PSA levels: prostatitis (prostate inflammation), benign prostatic hypertrophy (prostate enlargement), and prostate cancer. PSA levels can also be influenced by a number of other things. Some prostate glands normally produce more PSA than others. PSA levels tend to increase with age. And, PSA levels can vary with race: African Americans often have higher PSA levels; Asian men often have lower PSA levels.

As a screening tool, PSA is controversial because it is not yet proven to save lives. Formal clinical trials are currently underway to determine whether screening lowers the death rate from prostate cancer.

Biopsy and Transrectal Ultrasound (TRUS)

If either the DRE or PSA are abnormal, a biopsy is recommended. Some 20% of men with prostate cancer detected on biopsy have a normal PSA, and many with elevated levels of PSA do not have cancer. Transrectal Ultrasound (TRUS) may be used to guide the needle biopsy or to assess the size of the prostate gland. During the TRUS, a small probe (about the size of an index finger) is inserted into the rectum. The probe sends out high frequency sound waves. These sound waves bounce off the prostate gland producing an echo pattern that a computer converts into a picture (sonogram) of the prostate gland. The doctor can look for tissue patterns to distinguish between healthy and abnormal tissue.

National Prostate Cancer Awareness Week

The Prostate Cancer Education Council established the National Prostate Cancer Awareness Week in 1989 with the goals of educating people about prostate cancer and offering low-cost or free prostate cancer screening to men across the country. This annual event will be held September 17-21, 2001. Visit the Council’s Web at www.pcaw.com or call 1-888-755-PCAWfor more information

Philana Chen, MPH

Betty May, MS

References

1. Walsh, Patrick C. The Prostate: A Guide for Men and The Women Who Love Them, Warner Books, Inc. New York, 1997.

2. American Cancer Society Cancer Facts and Figures, 2001

3. National Cancer Institute Understanding Prostate Changes: A Health Guide for All Men, 1999.

4. CancerNet Web site: Screening for Prostate Cancer (PDQ), 2000. http://cancernet.nci.nih.gov

5. National Cancer Institute Web site: Cancer Facts- Tumor Markers, 1998. http://cis.nci.nih.gov/fact/5_18.htm