Prostate Cancer Detection

The PSA Test and Digital Rectal Exam

Routine tests for detecting prostate cancer at an early, more treatable state include a blood test for prostate specific antigen (PSA) and a digital rectal exam. The two tests together are considered much better for detection than either test alone.

The PSA test detects a protein called PSA that is produced only by the prostate gland. PSA is not normally found in blood. However, small amounts of PSA may enter into the bloodstream in men with abnormal prostate conditions.

PSA exists in several different forms. Some forms are bound to proteins, and others are unbound (or “free”). Total PSA, as measured by your first PSA test, measures all of the PSA in your blood, both the protein-bound form and the free form. Your physician may request additional blood tests depending on the results of your total PSA test and your DRE.

In the test, a small sample of blood is taken from your arm and sent to a lab. There, it is analyzed for the amount of PSA. High levels of PSA do not harm you. They are only important as a signal to your doctor of possible prostate disease.

One of the most highly regarded total PSA tests is Beckman Coulter’s Hybritech PSA test.
For the digital rectal exam (DRE), your doctor will insert a gloved finger into the rectum, which enables him to feel the prostate gland. He is searching for areas of hardness or irregularity that may indicate prostate disease.

The age at which you should start getting a PSA test and a DRE performed should be determined by you and your physician. The same is true for the regularity – or time between tests – of routine testing. That said, many physicians will recommend that their male patients begin getting a PSA test and a DRE on a yearly basis beginning at age 50. If the patient has risk factors such as African-American heritage or a close relative who has had the disease, a doctor may recommend starting at 45, or in cases of especially high risk, even 40.

Free PSA

If your PSA level is above normal, and/or if your DRE reveals an area of hardness in the prostate, your doctor may recommend certain follow-up tests. Some of the most common include a free PSA test and a biopsy.

If your total PSA level is above normal, but your DRE appears normal, your physician may suggest a free PSA test. This may require that an additional blood sample be taken. The results of this test are compared to the results of the total PSA test to determine the percentage of PSA that is “free” (not bound to protein molecules). The higher the percentage of free PSA compared to total PSA, the more likely it is that the prostate condition is not cancerous. The test is useful in helping some men avoid unnecessary biopsies.

For more information on the Hybritech PSA and free PSA tests, click here.

Prostate Biopsy

A prostate biopsy involves the removal of a small amount of tissue from the prostate. Examination of the biopsied tissue under a microscope is the only way to be certain of the presence of prostate cancer.

A prostate biopsy is performed using transrectal ultrasound to allow precise placement of the biopsy needle through the rectum. In most cases, there is no need for anesthesia, and the procedure is usually done on an outpatient basis. Typically, the urologist will take a number of tissue samples from the prostate, with the precise sample number depending on what is visualized by the ultrasound machine.

The biopsy specimens are then sent to a pathologist for evaluation. The pathologist sends the urologist a report including the following: Which, if any, specimens contain cancer, the extent of malignancy in any specimens showing cancer, the location of malignancy in the specimens, and the grade or grades of cancer in each malignant specimen, if any.

About Your PSA Test Results

Why a High Total PSA Level Usually Doesn’t Mean Prostate Cancer

• Most men who have elevated total PSA levels and further diagnostic tests such as a prostate biopsy are found not to have prostate cancer.
  
• There are several conditions other than cancer that can cause the level of PSA in the bloodstream to rise. The most common of these is enlargement of the prostate gland, called benign prostatic hyperplasia (BPH). BPH is very common in men over 50 years of age, and may cause difficulty with urination. About four out of five men eventually develop enlarged prostates. BPH is not cancer, nor is there evidence that it leads to cancer. This condition can be treated by medication, surgery, or non-surgical alternatives such as microwave therapy.
  
• Higher than normal PSA levels can also be caused by a condition called prostatitis, which is an infection or inflammation of the prostate gland.
  
• The precentage of free PSA will help your physician determine if a high total PSA level may be caused by a non-cancerous condition such as BPH or prostatitis.
  

Why Annual PSA Tests Are an Excellent Idea Even if Your PSA Level is Normal

• There is an excellent reason to get annual total PSA tests even if your risk factors are low or your last total PSA test showed a low level of total PSA. The rate at which a man's PSA rises over time can indicate potential cancer. An increase of 20 percent to 30 percent in a single year may be cause for concern, even if the overall PSA is relatively low. (Eastham, JA, et al, JAMA 2003;289:2695).
  
• The starting age for getting annual tests should be determined by you and your physician, but many physicians recommend that their male patients begin getting an annual total PSA test at age 50. If you have any of these risk factors, your physician may advise that you start getting annual tests at a younger age.

Clinical laboratory tests results should be interpreted in light of the total clinical presentation of the patient, including symptoms, clinical history, data from additional tests and other appropriate information.

What Else a Healthcare Consumer Needs to Know About Prostate Cancer Detection

You can improve your prostate healthcare if you educate yourself about the prostate and prostate testing, and participate actively with your physician in making decisions about your health. No matter how conscientious and knowledgeable your physician is, he may appreciate being reminded about some of the following details about prostate cancer detection:

• Total PSA test. The original research on total PSA testing was conducted with a test called the Hybritech Tandem-R PSA test, offered by Beckman Coulter. It’s widely accepted that a level of 4.0 ng/mL or higher of total PSA cues physicians to recommend a follow-up test for percent-free PSA. This “cutoff level” was established by William Catalona, M.D., in clinical studies using the Hybritech test. (The Tandem-R tests were manual tests; Beckman Coulter now manufactures Access® PSA and free PSA tests, which are run on an automated analyzer. References in this site refer to the Access methods, unless otherwise noted.)

Some PSA tests produced by other manufacturers were developed to align to the Hybritech method and cutoff level, but others were not. In other words, all PSA tests are not standardized. You should verify with your physician that your test result for total PSA is matched to the manufacturer’s cutoff level for the test that was used.

• Free PSA test. If your total PSA level is above normal, but your DRE appears normal, your physician may suggest the Hybritech free PSA test. The results of this test are compared to the results of the total PSA test to determine how much of your PSA is free-floating in your bloodstream as opposed to bound to protein molecules (thus the name free PSA). The higher the percentage of free PSA to total PSA, the more likely it is that the prostate condition is not cancerous. The test is useful in helping men avoid unnecessary biopsies. It is important that total PSA and free PSA tests be calibrated to each other, because the percent free PSA result is based on the total PSA result. That is, it is expressed as a percentage of the level of total PSA.

Therefore, it is highly recommended that a patient’s total PSA test and free PSA test be by the same manufacturer, be done at the same lab, and follow cutoff guidelines made by that manufacturer. For example, a patient whose total PSA was measured with the Hybritech test should have his free PSA measured by the Hybritech method to determine his percent free PSA.

For more information on the Hybritech PSA and free PSA tests for determining your percent free PSA, click here.

• Serial measurement. Your physician may compare this year’s total PSA result to last year’s and look for any suspicious rise in concentration. Because all PSA tests are not standardized, it is important to get each year’s PSA test performed at the same lab using the same test so that “apples are compared to apples.” For example, if your test last year was performed at the ABC Hospital using the Hybritech test, it should be performed at the same hospital this year with the Hybritech test, as well.