Prostate Cancer Testing

Scientists are trying to better understand which people are more likely to get certain types of cancer. They also study the things we do and the things around us to see if they cause cancer. This information helps doctors recommend who should be screened for cancer, which screening tests should be used, and how often the tests should be done.

It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms. Screening tests may be repeated on a regular basis.

If a screening test result is abnormal, you may need to have more tests done to find out if you have cancer. These are called diagnostic tests.

What are common tests for prostate changes?
Abnormal findings from any of these tests can help diagnose a problem and suggest the next steps to take:

• DRE (digital rectal exam): an examination of the prostate
• PSA (prostate-specific antigen) test: a blood test
• Biopsy: a test to check for cancer

Can prostate cancer be found before a man has symptoms?
Yes. Two tests can be used to detect prostate cancer in the absence of any symptoms. One is the digital rectal exam (DRE), in which a doctor feels the prostate through the rectum to find hard or lumpy areas. The other is a blood test used to detect a substance made by the prostate called prostate specific antigen (PSA). Together, these tests can detect many “silent” prostate cancers, those that have not caused symptoms.

How reliable are the screening tests for prostate cancer?
Neither of the screening tests for prostate cancer is perfect. Most men with mildly elevated PSA levels do not have prostate cancer, and many men with prostate cancer have normal levels of PSA. PSA is the prostate-specific antigen test. Also, the DRE can miss many prostate cancers. DRE is the digital rectal exam. The DRE and PSA test together are better than either test alone in detecting prostate cancer.

What is a DRE?
One is the digital rectal exam (DRE), in which a doctor feels the prostate through the rectum to find hard or lumpy areas.

What is PSA?
The initials, PSA, stand for prostate specific antigen. PSA is a protein produced by the cells of the prostate gland. The PSA test measures the level of PSA in the blood. The doctor takes a blood sample, and the amount of PSA is measured in a laboratory. Because PSA is produced by the body and can be used to detect disease, it is sometimes called a tumor marker. A tumor marker is a substance sometimes found in the blood, other body fluids, or tissues. A high level of tumor marker may mean that a certain type of cancer is in the body.
It is normal for men to have low levels of PSA in their blood; however, prostate cancer or other conditions can increase PSA levels. As men age, both prostate cancer and other prostate conditions become more frequent. The most common benign prostate conditions are prostatitis (inflammation of the prostate) and benign prostatic hyperplasia (BPH) (enlargement of the prostate). There is no evidence that prostatitis or BPH cause cancer, but it is possible for a man to have one or both of these conditions and to develop prostate cancer as well.

Most men with an elevated PSA test turn out not to have cancer; only 25 to 30 percent of men who have a biopsy due to elevated PSA levels actually have prostate cancer.

PSA levels alone do not give doctors enough information to distinguish the presence of cancer. However, the doctor will take the result of the PSA test into account when deciding whether to check further for signs of prostate cancer.

Why is the PSA test performed?
The U.S. Food and Drug Administration (FDA) has approved the PSA test along with a digital rectal exam (DRE) to help detect prostate cancer in men age 50 and older. During a DRE, a doctor inserts a gloved finger into the rectum and feels the prostate gland through the rectal wall to check for bumps or abnormal areas. Doctors often use the PSA test and DRE as prostate cancer screening tests; together, these tests can help doctors detect prostate cancer in men who have no symptoms of the disease.

The FDA has also approved the PSA test to monitor patients with a history of prostate cancer to see if the cancer has come back. An elevated PSA level in a patient with a history of prostate cancer does not always mean the cancer has come back. A man should discuss an elevated PSA level with his doctor. The doctor may recommend repeating the PSA test or performing other tests to verify the existence of cancer.

It is important to note that a man who is receiving hormone therapy for prostate cancer may have a low PSA reading during, or immediately after, treatment. The low level may not be a true measure of PSA activity in the man’s body. Men receiving hormone therapy should talk with their doctor, who may advise them to wait a few months after hormone treatment before having a PSA test.

Who should have a PSA screening test?
Doctors’ recommendations for screening vary. Some encourage yearly screening for men over age 50, and some advise men who are at a higher risk for prostate cancer to begin screening at age 40 or 45. Others caution against routine screening, while still others counsel men about the risks and benefits on an individual basis and encourage men to make personal decisions about screening. Currently, Medicare provides coverage for an annual PSA test for all men age 50 and older.

Several risk factors increase a man’s chances of developing prostate cancer. These factors may be taken into consideration when a doctor recommends screening. Age is the most common risk factor, with nearly 70 percent of prostate cancer cases occurring in men age 65 and older. Other risk factors for prostate cancer include family history of prostate cancer, race, and possibly diet. Men who have a father or brother with prostate cancer have a greater chance of developing prostate cancer. African American men have the highest rate of prostate cancer, while Asian and Native American men have the lowest rates. In addition, there is some evidence that a diet higher in fat, especially animal fat, may increase the risk of prostate cancer.

How are PSA test results reported?
PSA test results report the level of PSA detected in the blood. The test results are usually reported as nanograms of PSA per milliliter(ng/ml) of blood. In the past, most doctors considered PSA values below 4.0 ng/ml as normal. However, recent research found prostate cancer in men with PSA levels below 4.0 ng/ml. Many doctors are now using the following ranges, with some variation:

• 0 to 2.5 ng/ml is low
• 2.6 to 10 ng/ml is slightly to moderately elevated
• 10 to 19.9 ng/ml is moderately elevated
• 20 ng/ml or more is significantly elevated

There is no specific normal or abnormal PSA level. However, the higher a man’s PSA level, the more likely it is that cancer is present. But because various factors can cause PSA levels to fluctuate, one abnormal PSA test does not necessarily indicate a need for other diagnostic tests. When PSA levels continue to rise over time, other tests may be needed.

What if the test results show an elevated PSA level?
A man should discuss elevated PSA test results with his doctor. There are many possible reasons for an elevated PSA level, including prostate cancer, benign prostate enlargement, inflammation, infection, age, and race.

If no other symptoms suggest cancer, the doctor may recommend repeating DRE and PSA tests regularly to watch for any changes. If a man’s PSA levels have been increasing or if a suspicious lump is detected during the DRE, the doctor may recommend other tests to determine if there is cancer or another problem in the prostate. A urine test may be used to detect a urinary tract infection or blood in the urine. The doctor may recommend imaging tests, such as ultrasound (a test in which high-frequency sound waves are used to obtain images of the kidneys and bladder), x-rays, or cystoscopy (a procedure in which a doctor looks into the urethra and bladder through a thin, lighted tube). Medicine or surgery may be recommended if the problem is BPH or an infection.

Neither of the screening tests for prostate cancer is perfect. Most men with mildly higher PSA (prostate specific antigen) levels do not have prostate cancer, and many men with prostate cancer have normal levels of PSA. Also, the DRE (digital rectal exam) can miss many prostate cancers. The DRE and PSA test together are better than either test alone in detecting prostate cancer.

If cancer is suspected, a biopsy is needed to determine if cancer is present in the prostate. During a biopsy, samples of prostate tissue are removed, usually with a needle, and viewed under a microscope. The doctor may use ultrasound to view the prostate during the biopsy, but ultrasound cannot be used alone to tell if cancer is present.

What are some of the limitations of the PSA test?

• Detection does not always mean saving lives: Even though the PSA test can detect small cancerous tumors, finding a small tumor does not necessarily reduce a man’s chance of dying from prostate cancer. PSA testing may identify very slow-growing tumors that are unlikely to threaten a man’s life. Also, PSA testing may not help a man with a fast-growing cancer that has already spread to other parts of his body before being detected.
• False positive tests: False positive test results (also called false positives) occur when the PSA level is elevated but no cancer is actually present. False positives may lead to additional medical procedures that have potential risks and significant financial costs and can create anxiety for the patient and his family. Most men with an elevated PSA test turn out not to have cancer; only 25 to 30 percent of men who have a biopsy due to elevated PSA levels actually have prostate cancer (3).
• False negative tests: False negative test results(also called false negatives) occur when the PSA level is in the normal range even though prostate cancer is actually present. Most prostate cancers are slow-growing and may exist for decades before they are large enough to cause symptoms. Subsequent PSA tests may indicate a problem before the disease progresses significantly.

Why is the PSA test controversial?
Using the PSA test to screen men for prostate cancer is controversial because it is not yet known if this test actually saves lives. Moreover, it is not clear if the benefits of PSA screening outweigh the risks of follow-up diagnostic tests and cancer treatments. For example, the PSA test may detect small cancers that would never become life threatening. This situation, called overdiagnosis, puts men at risk for complications from unnecessary treatment such as surgery or radiation.

The procedure used to diagnose prostate cancer (prostate biopsy) may cause side effects, including bleeding and infection. Prostate cancer treatment may cause incontinence (inability to control urine flow) and erectile dysfunction (erections inadequate for intercourse). For these reasons, it is important that the benefits and risks of diagnostic procedures and treatment be taken into account when considering whether to undertake prostate cancer screening.

What research is being done to validate and improve the PSA test?
The benefits of screening for prostate cancer are still being studied. The National Cancer Institute (NCI) is currently conducting the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, or PLCO trial, to determine if certain screening tests reduce the number of deaths from these cancers. The DRE and PSA are being studied to determine whether yearly screening to detect prostate cancer will decrease a man’s chance of dying from prostate cancer. Full results from this study are expected in several years. Scientists also are researching ways to distinguish between cancerous and benign conditions, and between slow-growing cancers and fast-growing, potentially lethal cancers. Some of the methods being studied are:

• PSA velocity: PSA velocity is based on changes in PSA levels over time. A sharp rise in the PSA level raises the suspicion of cancer.
• Age-adjusted PSA: Age is an important factor in increasing PSA levels. For this reason, some doctors use age-adjusted PSA levels to determine when diagnostic tests are needed. When age-adjusted PSA levels are used, a different PSA level is defined as normal for each 10-year age group. Doctors who use this method generally suggest that men younger than age 50 should have a PSA level below 2.4 ng/ml, while a PSA level up to 6.5 ng/ml would be considered normal for men in their 70s. Doctors do not agree about the accuracy and usefulness of age-adjusted PSA levels.
• PSA density: PSA density considers the relationship of the PSA level to the size of the prostate. In other words, an elevated PSA might not arouse suspicion if a man has a very enlarged prostate. The use of PSA density to interpret PSA results is controversial because cancer might be overlooked in a man with an enlarged prostate.
• Free versus attached PSA: PSA circulates in the blood in two forms: free or attached to a protein molecule. With benign prostate conditions, there is more free PSA, while cancer produces more of the attached form. Researchers are exploring different ways to measure PSA and to compare these measurements to determine if cancer is present.
• Alteration of PSA cutoff level: Some researchers have suggested lowering the cutoff levels that determine if a PSA measurement is normal or elevated. For example, a number of studies have used cutoff levels of 2.5 or 3.0 ng/ml (rather than 4.0 ng/ml). In such studies, PSA measurements above 2.5 or 3.0 ng/ml are considered elevated. Researchers hope that using these lower cutoff levels will increase the chance of detecting prostate cancer; however, this method may also increase overdiagnosis and false positive test results and lead to unnecessary medical procedures.
• Protein patterns: Scientists are also studying a test that can rapidly analyze the patterns of various proteins in the blood. Researchers hope that this technique can determine if a biopsy is necessary when a person has a slightly elevated PSA level or an abnormal DRE.

What is a biopsy and do I need a biopsy?
A biopsy is the surgical removal of tissue samples, while under local anesthesia in a doctor’s office. Anesthesia is drugs or substances that cause a loss of feeling or awareness. The biopsy is done by a urologist, a doctor who specializes in diseases of the sex organs and urinary tract, the organs of the body that produce and discharge urine. Then a pathologist, a doctor who identifies diseases by studying tissues under a microscope, checks the patient’s tissue for signs of cancer. A biopsy is needed in order to confirm a diagnosis of prostate cancer.

How is prostate cancer diagnosed?
The diagnosis of prostate cancer can be confirmed only by a biopsy. A biopsy is the surgical removal of tissue samples, while under local anesthesia, drugs or substances that cause a loss of feeling or awareness, in a doctor’s office. The biopsy is done by a urologist, a doctor who specializes in diseases of the sex organs and urinary tract, the organs of the body that produce and discharge urine. Then a pathologist, a doctor who identifies diseases by studying tissues under a microscope, checks the patient’s tissue for signs of cancer.

What questions should I ask my physician?
No written information can take the place of talking directly with your health care professionals. If you don't understand the answers to your questions, ask the doctor or his/her staff to explain further.

Many men find it helpful to write down their questions ahead of time. Below are some of the most common questions. You may have others. Jot them down as you think of them, and take the list with you when you see your physician.

• Could my symptoms be a sign of cancer?
• What tests do you recommend? Why?
• If I don't have cancer, what can I do about my symptoms?
• If I do have cancer, what stage is it? What grade? What is my PSA level?
• Would it be useful to get a second opinion from a second pathologist?
• What is my prognosis? Is recurrence likely?
• Do I need additional tests to look for lymph node involvement or metastases?
• What are my treatment options? What are the benefits?
• What are the possible side effects? How can they be managed?
• Are there clinical trials that would be appropriate for me?
• What other doctors should I talk with-a cancer specialist, a surgeon, a radiation oncologist?
• How much experience does your physician have? How many times a year does your physician perform this procedure? If a surgeon, is he familiar with nervesparing techniques?

Should I seek a second opinion?
Once you receive your doctor's opinion about what treatments you need, it may be helpful to get more advice before you make up your mind. Other doctors' opinions can help you make one of the most important decisions of your life. Getting another doctor's advice is normal medical practice, and your doctor can help you with this effort. Many health insurance companies require and will pay for other opinions. Another opinion can help you:

• Confirm or adjust your treatment plan based on the diagnosis and stage of the disease.
• Get answers to your questions and concerns and help you become comfortable with your decisions.
• Decide about taking part in clinical trials of new prostate cancer treatment methods.

You may also consider contacting a prostate cancer support group in your area. Talking with other men who have experienced the various procedures available may help you to understand better the treatment options described by your doctor.