Web Exclusive: Finding Prostate Cancer Early

CURE, Special Issue 2006, Volume 5, Issue 3

The goal of screening for prostate cancer is to find cancer early, before it starts to cause symptoms, in the hope that it can be treated more effectively.

The goal of screening for prostate cancer is to find cancer early, before it starts to cause symptoms, in the hope that it can be treated more effectively.

Prostate cancer can often be found early by testing the amount of prostate-specific antigen (PSA) in your blood. Prostate cancer can also be found early when the doctor performs a digital rectal exam. Because your prostate gland lies just in front of your rectum, the doctor can feel for any nodules or areas of abnormal hardness, which often indicate that cancer is present.

If prostate cancer is detected during routine yearly exams with the PSA test or digital rectal exam, your cancer will probably be at an early, more treatable stage. On the other hand, there are potential problems with the current screening methods. Neither the PSA test nor the digital rectal exam is 100 percent accurate. Inconclusive or false results on testing could cause confusion and anxiety. Some men might undergo a prostate biopsy (which carries its own small risks) when cancer is not present, while others might get a false sense of security from normal test results when cancer is actually present. Until more information is available, you and your doctor must decide whether you should have the PSA test.

The American Cancer Society believes that healthcare professionals should offer the PSA blood test and digital rectal exam yearly, beginning at age 50, to men who have at least a 10-year life expectancy. Men at high risk, such as African Americans and men who have a first-degree relative (father, brother or son) diagnosed with prostate cancer at an early age (younger than age 65), should begin testing at age 45.

Men at even higher risk (because they have several first-degree relatives who had prostate cancer at an early age) could begin testing at age 40. Depending on the results of this initial test, further testing might not be needed until age 45.

Doctors should give men the opportunity to openly discuss the benefits and risks of testing at annual checkups. Men should be involved in the decision by learning about prostate cancer and the pros and cons of early detection and treatment. No major scientific or medical organizations, including the ACS, American Urological Association, U.S. Preventive Services Task Force, American College of Physicians, National Cancer Institute, American Academy of Family Physicians and American College of Preventive Medicine advocate routine testing for prostate cancer in men at average risk. The USPSTF has concluded that studies completed so far do not provide enough evidence to determine whether the benefits of testing for early prostate cancer outweigh the disadvantages.

The PSA test (and its variations described below) can’t tell for sure whether or not cancer is present. If the results of one or more of these tests are abnormal, you will likely need a prostate biopsy to determine if you have cancer.

Prostate-specific antigen is a substance made by the normal prostate gland. Although PSA is mostly found in semen, a small amount is also present in the blood. Most men have levels under 4 nanograms per milliliter (ng/mL) of blood.

When prostate cancer develops, the PSA level usually goes above 4. If your level is in the borderline range between 4 and 10, you have about a 25 percent chance of having prostate cancer. If it is more than 10, your chance of having prostate cancer is over 50 percent and increases further as your PSA level increases.

Your PSA level can be also affected by other factors, including non-cancerous enlargement of the prostate (called benign prostatic hyperplasia, or BPH), something many men develop as they grow older.

If your PSA level is high, your doctor may recommend a prostate biopsy to determine if you have cancer. Before doing that, however, there are some new types of PSA tests that might help determine if you need a prostate biopsy. Not all doctors agree on how to use these additional PSA tests. If your PSA test result is not normal, ask your doctor to discuss your cancer risk and your need for further tests.

Percent-free PSA: PSA occurs in two major forms in the blood. One is complexed (attached) to blood proteins and the other circulates free (unattached). The percent-free PSA test indicates how much PSA circulates free compared to the total PSA level. The percentage of free PSA is lower in men who have prostate cancer than in men who do not. This test is useful in helping decide whether men with a total PSA between 4 and 10 may need a biopsy.

PSA velocity: The PSA velocity is not a separate test, but a measure of how fast the PSA rises over time. Even when the total PSA value isn’t over 4, a high PSA velocity suggests that cancer may be present and a biopsy should be considered. For example, if your PSA was 1.7 and then rose to 3.8 a year later, the rapid rise might be cause for concern.

PSA density: The PSA density is used for men with large prostate glands. The doctor determines the volume of the prostate gland with transrectal ultrasound and divides the PSA number by the prostate volume. A higher PSA density indicates greater likelihood of cancer. PSA density may be useful, but the percent-free PSA test has thus far been shown to be more accurate.

There is no question that the PSA test can help spot prostate cancer. But it can’t tell how dangerous the cancer is. The problem is that some prostate cancers are slow growing and may never cause problems. Yet some patients who might not die from their cancer are being treated with either surgery or radiation because they are uncomfortable not having treatment. Doctors and patients are still struggling to decide who should receive treatment and who can be followed without treatment.

For more information on issues of screening and other cancer topics, visit the American Cancer Society’s website. And read about prostate cancer prevention in CUREXtra.

©American Cancer Society