No Single Answer for Testing or Treatment - Part 2
Detecting Prostate Cancer
The prostate is a male sex gland, about the size of a walnut. It produces a thick fluid that helps propel sperm through the urethra and out of the penis during sex. Because the prostate is just below the bladder and directly in front of the rectum, a doctor can check the size and condition of the gland by inserting a rubber-gloved finger into the rectum. This digital rectal exam (DRE) has for years been the gold standard for detecting prostate cancer as well as the noncancerous disorder benign prostatic hyperplasia (
see Noncancerous Prostate Disorder)
In 1985, FDA approved the first test for monitoring blood levels of a substance called prostate specific antigen (PSA), which, when elevated, can indicate cancer presence. Several companies now have approved PSA tests, which, experts say, have revolutionized the screening and monitoring of patients.
PSA is an ideal marker for prostate cancer because it is basically restricted to prostate cells. A healthy prostate will produce a stable amount--typically below 4 nanograms per milliliter, or a PSA reading of "4" or less--whereas cancer cells produce escalating amounts that correspond with the severity of the cancer. A level between 4 and 10 may raise a doctor's suspicion that a patient has prostate cancer, while amounts above 50 may show that the tumor has spread elsewhere in the body.
Most PSA tests measure "total PSA," or the amount that is bound to blood proteins. In 1998, FDA approved the Tandem R test, which measures not only total PSA but another component called "free PSA," which floats unbound in the blood. Comparing the two helps doctors rule out cancer in men whose PSA is mildly elevated from other causes. A 1995 study in the Journal of the American Medical Association showed that the free PSA test can reduce unnecessary prostate biopsies by 20 percent in patients with a PSA between 4 and 10.
The availability of increasingly sensitive testing devices has created a debate over when men should be tested for prostate cancer, how often, and whether men under 50 with no symptoms should be routinely screened. Opponents say mass screening would be expensive, and the verdict is still out on whether early detection can curb the disease's mortality rate. But proponents say early detection is the closest thing currently to a cure and that it can save lives. The American Cancer Society and the American Urological Association recommend annual PSA tests--along with the digital exam--for all men over 50 and for high-risk men over 40.
The PSA test, though a powerful tool, "is not perfect," says Jean Fourcroy, M.D., a urologist and medical officer in FDA's Center for Devices and Radiological Health. Besides being thrown off by noncancerous conditions, the tests can vary between manufacturers. "Patients and physicians should use the same brand of PSA test throughout monitoring because of these possible variations," Fourcroy says.
When PSA or digital tests indicate a strong likelihood that cancer is present, doctors usually order a transrectal ultrasound (TRUS), a probe inserted into the rectum that uses sound waves to "map" the prostate and show any suspicious areas. Doctors then may take biopsies of various sectors of the prostate using tiny hollow needles inserted through the rectum. Biopsies are the only definitive way to determine if prostate cancer is present.
If the biopsy indicates cancer, the doctor then
"stages" the tumor based on which biopsy specimens contain cancer, the extent of cancer, and the location of cancer in the specimens. Staging also depends on the extent and location of cancer outside the confines of the prostate.
Another important measure, the Gleason score, gauges the probable aggressiveness of the tumor based on the cellular differences of the cancer. Tumor cells that look similar to normal cells tend to be less aggressive, while those distributed randomly with uneven edges are likely to spread rapidly. Two numbers, each from 1 to 5, are assigned. The higher the numbers when the two are added, the more aggressive the tumor is likely to be.
Doctors also examine the ploidy, or number of sets of chromosomes in a cancer cell. Diploid cells, for example, have a complete set of normally paired chromosomes, and tend to grow slowly and respond well to therapy.
Recently, some doctors have begun using Partin Tables, a scoring method developed at Johns Hopkins University that uses PSA, Gleason number, and staging to predict if the disease is confined or has spread to other sites. Doctors also can determine cancer spread with imaging techniques such as bone scans and computerized tomography (CT) scans.
Read more about how doctors are treating the disease.
Along with the abundance now of printed prostate materials, the burgeoning popularity of the Internet has helped spawn a new breed of prostate cancer patient, a well-informed man who is in charge of his destiny. Huge amounts of reliable material from organizations such as the American Cancer Society, the National Cancer Institute, and the physicians with Advanced Healthcare and Columbia St. Mary's here in the Milwaukee area are available online.
Patients also are using the Internet to connect with fellow patients through electronic mailing lists. This allows them to compare notes and get feedback on treatment decisions. Many prostate cancer doctors post messages to mailing lists and answer patient questions.
"I'm not sure I'd be alive today if it weren't for information I've gotten on the Internet," says prostate cancer patient Russ Ingram, who has located experts online who have helped him select the latest treatments for his spreading cancer.
--J.H.
For More Information
Contact any of these organizations for more on prostate cancer, support groups, and joining Internet mailing lists.
American Cancer Society
1-800-ACS-2345 (1-800-227-2345)
www.cancer.org
American Foundation for Urologic Disease
1128 N. Charles St.
Baltimore, MD 21201
1-800-828-7866
National Cancer Institute
Building 31, Room 10A03
31 Center Drive, MSC 2580
Bethesda, MD 20892-2580
1-800-4-CANCER (1-800-422-6237)
www.cancer.gov
National Prostate Cancer Coalition
1158 15th St., N.W.
Washington, DC 20005
(202) 463-9455
www.4npcc.org
US Too International Inc.
930 N. York Road, Suite 50
Hinsdale, IL 60521-2993
1-800-808-7866
www.ustoo.com
Source: This article originally appeared in the September-October 1998 FDA Consumer and contains revisions made in May 2000. The article is no longer being updated. For related information on this topic, visit http://www.fda.gov/cder/cancer/index.htm.
