What is a PSA test?

Prostate-specific antigen (PSA) is a protein produced by both cancerous (malignant) and noncancerous (benign) prostate tissue. PSA helps liquefy the semen. A small amount enters the bloodstream. Cancer cells usually make more PSA than do benign cells, causing PSA levels in your blood to rise. However, determining what a high PSA score means can be complicated. Besides the PSA number itself, your doctor will consider a number of other factors to evaluate your PSA scores:

* Your age

* The size of your prostate gland

* How quickly your PSA levels are changing

* Whether you're taking medications that affect PSA measurements, such as finasteride (Propecia, Proscar), dutasteride (Avodart) and even some herbal supplements

When elevated PSA isn't cancer

While high PSA levels can be a sign of prostate cancer, a number of conditions other than prostate cancer also can cause PSA levels to rise. These other conditions could cause what's known as a "false-positive" — meaning a result that falsely indicates you might have prostate cancer when you don't. Conditions that could lead to an elevated PSA level in men who don't have prostate cancer include:

* Benign prostate enlargement (benign prostatic hyperplasia)

* A prostate infection (prostatitis)

* Other less common conditions

False-positives are common. Only about one in four men who have a positive PSA test turns out to have prostate cancer.

Why you Should Consider a Prostate Cancer Psa Test Today

Prostate Cancer kills if allowed to grow. If ever there was a good reason to have a simple blood test, this is it. The Prostate cancer PSA (Prostate Specific Antigen) test is one of the tests given to determine if cancer cells are present in an otherwise healthy prostate. It is a simple blood test to help doctors diagnose and identify the existence of prostate cancer.

The PSA test, although considered a prostate specific test is not really an absolute definitive test for the cancer. Depending on the research conducted, the PSA test is known to be somewhere between 85 and 95% accurate in identifying prostate cancer.

While an elevated PSA test may suggest the presence of prostate cancer, it's not an absolute. If however you have an elevated result, your doctor will probably want to do additional testing for a more complete and accurate assessment of the potential cancer. The last thing you want to do is to allow prostate cancer to grow beyond the prostate gland.

The good news is that BPH or Benign Prostatic Hyperplasia, better known as an enlarged prostate can also elevate the PSA test results. Even Prostatitis and Lower Urinary Tract symptoms can show elevated levels of PSA so if you have an elevated test result don't panic! A normal result from a PSA test, doesn't guarantee that your free from cancer, nor does a higher than normal result means you do have cancer

It's critical that you follow your doctor's lead in regard to dealing with the Prostate Specific Antigen test results. The results are an indication in a tool only to develop a complete diagnosis. To complicate matters more, PSA levels can also increase with age. Oh and the relative size of your prostate also plays a factor in interpreting the results.

Remember that as many as two out of three people with elevated the PSA readings DO NOT have a malignancy

Here's a quick list of the benefits and reasons why you should consider getting a PSA test

1. It's possible to detect a cancerous condition before any symptoms are known

2. Early detection catches prostate cancer before it is spread increasing the chances of a complete cure

3. The PSA blood test has been recognized as a contributing factor that has significantly reduced the number of prostate cancer death

The PSA test also delivers a false positive, which is a normal PSA level in about 20% of the time. It is still recognized as a good indicator of potential cancerous conditions and should be taken seriously. A 2005 Harvard study indicated that men having an annual PSA test were almost 3 times LESS likely to die of prostate cancer than men who didn't bother with the test. So the best reason to have the test is that without it, you greatly increase the chances of dying from prostate cancer!

What if the test results show a rising PSA level after treatment for prostate cancer?

A man should discuss rising PSA test results with his doctor. Doctors consider a number of factors before recommending further treatment. Additional treatment based on a single PSA test result is often not recommended. Rather, a rising trend in PSA test results over a period of time combined with other findings, such as an abnormal DRE, positive prostate biopsy results, or abnormal CT (computed tomography) scan results, may lead to a recommendation for further treatment.

According to the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology for Prostate Cancer (4), additional treatment may be indicated based on the following PSA test results:

* For men who have been in the watchful waiting phase—their PSA level has doubled in fewer than 3 years or they have a PSA velocity (change in PSA level over time) of greater than 0.75 ng/mL per year, or they have a prostate biopsy showing evidence of worsening cancer (4).

* For men who have had a radical prostatectomy (removal of the prostate gland)—their PSA level does not fall below the limits of detection after surgery or they have a detectable PSA level (> 0.3 ng/mL) that increases on two or more subsequent measurements after having no detectable PSA (4).

* For men who have had other initial therapy, such as radiation therapy with or without hormonal therapy—their PSA level has risen by 2 ng/mL or more after having no detectable PSA or a very low PSA level (4).

Please note that these are general guidelines. Prostate cancer is a complex disease and many variables need to be considered by each patient and his doctor.

What is a normal PSA level?

Most authorities agree that if you have a PSA greater than 4 ng/ml, you should have further investigations. Some suggest that if your PSA is greater than the 'normal for age' range shown in Table 1, or if it is rising rapidly, it should be investigated.

Depending on your age and family history, your doctor may then refer you directly to a Urologist, or may repeat the test before referring you for further investigation.

If cancer is present, the level of PSA in the blood rises as the tumour grows. This means that small rises in PSA are found in association with small tumours which may be still confined to the prostate gland (localised). PSA levels of 10ng/ml or less have the best chance of being localised 3. The PSA level and the cancerous characteristics of the tumour cells themselves (called "grade") can indicate the risk that a tumour has grown beyond the prostate.

If cancer is present, the rate at which the PSA level increases over a series of tests (called PSA velocity) also gives information about the risk that cancer will recur after treatment

Why is the PSA test controversial in screening?

Using the PSA test to screen men for prostate cancer is controversial because it is not yet known for certain whether this test actually saves lives. Moreover, it is not clear that 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 of complications from unnecessary treatment.

The procedure used to diagnose prostate cancer (prostate biopsy) may cause harmful side effects, including bleeding and infection. Prostate cancer treatments, such as surgery and radiation therapy, may cause incontinence (inability to control urine flow), erectile dysfunction (erections inadequate for intercourse), and other complications. 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 is the PSA test and who might have it done?

It is a blood test that measures the level of PSA in your blood. PSA stands for Prostate Specific Antigen. PSA is a protein made by the prostate which naturally leaks into the bloodstream.

Some men with symptoms of a prostate problem may consider having the test. The symptoms of benign prostate enlargement can be similar to the symptoms of a developing prostate cancer. Some men without any symptoms consider having the test to 'screen' for prostate cancer.

However, in both of these situations, the decision to have a PSA test is controversial as there are pros and cons.

Why is the PSA test performed?

The U.S. Food and Drug Administration (FDA) has approved the use of the PSA test along with a digital rectal exam (DRE) to help detect prostate cancer in men 50 years of age or 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 use of the PSA test to monitor patients who have a history of prostate cancer to see if the cancer has recurred (come back). If a man’s PSA level begins to rise, it may be the first sign of recurrence. Such a “biochemical relapse” typically precedes clinical signs and symptoms of a relapse by months or years. However, a single elevated PSA measurement in a patient with a history of prostate cancer does not always mean the cancer has come back. A man who has been treated for prostate cancer should discuss an elevated PSA level with his doctor. The doctor may recommend repeating the PSA test or performing other tests to check for evidence of a recurrence. The doctor may look for a trend of rising PSA measurements over time rather than a single elevated PSA level.

It is important to note that a man who is receiving hormone therapy for prostate cancer may have a low PSA level during, or immediately after, treatment. The low level may not be a true measure of the man’s PSA level. 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.

When prostate cancer doesn't increase PSA

Some prostate cancers, particularly those that grow quickly, may not produce much PSA. In this case, you might have what's known as a "false-negative" — a test result that incorrectly indicates you don't have prostate cancer when you do.

Because of the complexity of these relating factors, it's important that a physician experienced in interpreting PSA levels evaluates your situation. You want to avoid unnecessary follow-up testing and treatment, but you want to be aware of false-negatives, so don't ignore warning signs.

What if I have got early prostate cancer?

Even if you are diagnosed as having prostate cancer, there is still some disagreement among experts as to when to treat it, and if so, what is the best treatment. The decision to treat depends on factors such as the type, grade and stage of the cancer. (See leaflet called Prostate Cancer for details.)

For example, there is no proof that treating early prostate cancers helps men live any longer than they would have done. Most men with early prostate cancer will not die as a result of it; in particular older men in their 70's or 80's, or those with a slow-growing cancer. Also, some of the treatments for prostate cancer can cause serious side effects in some cases.

What is the prostate-specific antigen (PSA) test?

Prostate-specific antigen (PSA) is a protein produced by 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 biological marker or a tumor marker.

It is normal for men to have a low level of PSA in their blood; however, prostate cancer or benign (not cancerous) conditions can increase a man’s PSA level. As men age, both benign prostate conditions and prostate cancer become more common. The most frequent 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 causes cancer, but it is possible for a man to have one or both of these conditions and to develop prostate cancer as well.

A man’s PSA level alone does not give doctors enough information to distinguish between benign prostate conditions and 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.

What's risky about a PSA test?

You may wonder how getting a test for prostate cancer could have a downside. After all, there's little risk involved in the test itself — it requires simply drawing blood for evaluation in a lab. However, there are some potential dangers once the results are in. These include:

* Worry about false-positive results caused by elevated PSA levels from something other than prostate cancer.

* Invasive, stressful, expensive or time-consuming follow-up tests.

* False reassurance from a PSA test that doesn't reveal cancer (false-negative), leading to a missed diagnosis of aggressive prostate cancer that needs treatment.

* Stress or anxiety caused by knowing you have a slow-growing prostate cancer that doesn't need treatment.

* Deciding to have surgery, radiation or other treatments that cause side effects that are more harmful than untreated cancer.

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), a component of the National Institutes of Health, is currently conducting the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, or PLCO trial, to determine whether certain screening tests can help reduce the number of deaths from these cancers. The PSA test and DRE are being evaluated to determine whether yearly screening to detect prostate cancer will decrease a man’s chances of dying from this disease.

Initial results from the trial showed that annual PSA testing for 6 years and annual DRE testing for 4 years (performed in the same years as the first four PSA tests) did not reduce the number of deaths from prostate cancer through a median follow-up period of 11.5 years (range 7.2 to 14.8 years) (5). At 7 years of follow-up, a point in time when follow-up of the participants was essentially complete, 23 percent more cancers had been diagnosed in the screening group than in the control group. In the control group, men were randomly assigned to “usual care.”

These results suggest that many men were diagnosed with, and treated for, cancers that would not have been detected in their lifetime without screening and, as a consequence, were exposed to the potential harms of unnecessary treatments, such as surgery and radiation therapy. Nevertheless, it remains possible that a small benefit from the earlier detection of these “excess” cancers could emerge with longer follow-up. Follow-up of the PLCO participants will continue, therefore, until all participants have been followed for at least 13 years.

In contrast, initial results from another large randomized, controlled trial of prostate cancer screening, called the European Randomized Study of Screening for Prostate Cancer (ERSPC), found a 20 percent reduction in prostate cancer deaths associated with PSA testing every 4 years (6). At the time the results were reported, the participants had been followed for a median of 9 years. The average number of PSA tests per participant in ERSPC was 2.1. Most participating centers in this study used a lower PSA cutoff value as an indicator of abnormality than was used in the PLCO trial (3.0 ng/mL versus 4.0 ng/mL). As in the PLCO trial, many more cancers were diagnosed in the screening group than in the control group. The ERSPC researchers estimated that 1,410 men would have to be screened and 48 additional cancers would have to be detected to prevent one death from prostate cancer (6).

Scientists are also researching ways to improve the PSA test, hopefully to allow cancerous and benign conditions, as well as slow-growing cancers and fast-growing, potentially lethal cancers, to be distinguished from one another. Some of the methods being studied include the following:

* PSA velocity: PSA velocity is the change in PSA level over time. A sharp rise in the PSA level raises the suspicion of cancer and may indicate a fast-growing cancer. A 2006 study found that men who had a PSA velocity above 0.35 ng/mL per year had a higher relative risk of dying from prostate cancer than men who had a PSA velocity less than 0.35 ng/mL per year (7). More studies are needed to determine if a high PSA velocity more accurately detects prostate cancer early.

* PSA density: PSA density considers the relationship between the level of PSA and the size of the prostate. In other words, an elevated PSA level 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. The free PSA test is more often used for men who have higher PSA values. Free PSA may help tell what kind of prostate problem a man has. With benign prostate conditions (such as BPH), there is more free PSA, while cancer produces more of the attached form. If a man’s attached PSA level is high but his free PSA level is not, the presence of cancer is more likely. In this case, more testing, such as a prostate biopsy, may be done. Researchers are exploring additional ways of measuring PSA and comparing these measurements to determine whether cancer is present.

* Alteration of PSA cutoff level: Some researchers have suggested lowering the cutoff levels used to determine whether 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. (See ERSPC trial results above.)