A video introduction to the PSA test.
What is the PSA test?
Prostate-specific antigen(PSA) is a protein produced by normal, as well as malignant, cancerous cells of the prostate gland.
The PSA test measures the level of PSA in a man’s blood. For this test, a blood sample is sent to a laboratory for analysis. The results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood.
The blood level of PSA is often elevated in men with prostate cancer, but can be elevated for different reasons. An elevated PSA test does not mean that you definitely have prostate cancer. In addition to prostate cancer, a number of benign (not cancerous) conditions can cause a man’s PSA level to rise. The most frequent benign prostate conditions that cause an elevation in PSA level are prostatitis (inflammation of the prostate) and benign prostatic hyperplasia (BPH) (enlargement of the prostate). There is no evidence that prostatitis or BPH leads to prostate cancer, but it is possible for a man to have one or both of these conditions and to develop prostate cancer as well.
Prostate Antigens were first discovered and tested in the 1970s and studies in normal men and men with prostate cancer were then performed in the late 1970s and early 1980s. The PSA test was originally approved by the FDA in 1986 to monitor the progression of prostate cancer in men who had already been diagnosed with the disease. In 1994, the FDA approved the use of the PSA test in conjunction with a digital rectal exam (DRE) to test asymptomatic men for prostate cancer.
There is no specific normal or abnormal level of PSA in the blood, and levels may vary over time in the same man. In the past, most doctors considered PSA levels of 4.0 ng/mL and lower as normal. Therefore, if a man had a PSA level above 4.0 ng/mL, doctors would often recommend a prostate biopsy to determine whether prostate cancer was present.
However, we know that truly normal PSA numbers are less than one for normal young men at low risk of prostate cancer. ANY PSA above 1.5 begins to increase the risk that you have prostate cancer.
A THRESHOLD VALUE for determing what PSA number to use for a biopsy is typically based on a man’s age and other risk factors for prostate cancer as well as his health status to deterimine his riks of dying from prostate cancer.
In addition, various factors can cause a man’s PSA level to fluctuate. For example, a man’s PSA level often rises if he has prostatitis or a urinary tract infection. Prostate biopsies and prostate surgery also increase PSA level. Conversely, some drugs—including finasteride and dutasteride, which are used to treat BPH—lower a man’s PSA level. PSA level may also vary somewhat across testing laboratories.
Another complicating factor is that studies to establish the normal range of PSA levels have been conducted primarily in populations of white men. Although expert opinions vary, there is no clear consensus regarding the optimal PSA threshold for recommending a prostate biopsy for men of any racial or ethnic group.
In general, however, the higher a man’s PSA level, the more likely it is that he has prostate cancer. Moreover, a continuous rise in a man’s PSA level over time may also be a sign of prostate cancer.
1. If a man is found to have an elevated PSA level, get another PSA test to confirm the original finding. If the PSA level is still high, then a man has to make a decision about getting further testing such as an MRI or a biopsy or choose to follow the PSA test over time.
2. If if a suspicious lump is detected during a DRE along with an elevated PSA most likely we are going to be discussing a biopsy of your prostate.
What is a prostate biopsy?
a prostate biopsy. During this procedure, multiple samples of prostate tissue are collected by inserting hollow needles into the prostate and then withdrawing them. Most often, the needles are inserted through the wall of the rectum (transrectal biopsy). A pathologistthen examines the collected tissue under a microscope. The doctor may use ultrasound to view the prostate during the biopsy, but ultrasound cannot be used alone to diagnose prostate cancer.
Is the PSA test recommended for prostate cancer screening?
Until about 2008, some doctors and professional organizations encouraged yearly PSA screening for men beginning at age 50. Some organizations recommended that men who are at higher risk of prostate cancer, including African American men and men whose father or brother had prostate cancer, begin screening at age 40 or 45. However, as more was learned about both the benefits and harms of prostate cancer screening, a number of organizations began to caution against routine population screening. Most organizations recommend that men who are considering PSA screening first discuss the risks and benefits with their doctors.
Currently, Medicare provides coverage for an annual PSA test for all Medicare-eligible men age 50 and older. Many private insurers cover PSA screening as well.
What are some of the limitations and potential harms of the PSA test for prostate cancer screening? Why is it so controversial?
Detecting prostate cancer early may not reduce the chance of dying from prostate cancer.
When used in screening, the PSA test can help detect small tumors that do not cause symptoms. Finding a small tumor, however, may not necessarily reduce a man’s chance of dying from prostate cancer. Many tumors found through PSA testing grow so slowly that they are unlikely to threaten a man’s life. Detecting tumors that are not life threatening is called “overdiagnosis,” and treating these tumors is called “overtreatment.”
Overtreatment exposes men unnecessarily to the potential complications and harmful side effects of treatments for early prostate cancer, including surgery and radiation therapy. The side effects of these treatments include urinary incontinence (inability to control urine flow), problems with bowel function, erectile dysfunction (loss of erections, or having erections that are inadequate for sexual intercourse), and infection.
In addition, finding cancer early may not help a man who has a fast-growing or aggressive tumor that may have spread to other parts of the body before being detected.
The PSA test may give false-positive or false-negative results. A false-positive test result occurs when a man’s PSA level is elevated but no cancer is actually present. A false-positive test result may create anxiety for a man and his family and lead to additional medical procedures, such as a prostate biopsy, that can be harmful. Possible side effects of biopsies include serious infections, pain, and bleeding.
Most men with an elevated PSA level turn out not to have prostate cancer; only about 25% of men who have a prostate biopsy due to an elevated PSA level actually are found to have prostate cancer when a biopsy is done (2).
A false-negative test result occurs when a man’s PSA level is low even though he actually has prostate cancer. False-negative test results may give a man, his family, and his doctor false assurance that he does not have cancer, when he may in fact have a cancer that requires treatment.
Are there other tests?
How is the PSA test used in men who have been treated for prostate cancer?
The PSA test is often used to monitor patients who have a history of prostate cancer to see if their cancer has recurred (come back). If a man’s PSA level begins to rise after prostate cancer treatment, it may be the first sign of a recurrence. Such a “biochemical relapse” typically appears months or years before other clinical signs and symptoms of prostate cancer recurrence.
However, a single elevated PSA measurement in a patient who has a history of prostate cancer does not always mean that 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 level over time rather than a single elevated PSA level.
What does an increase in PSA level mean for a man who has been treated for prostate cancer?
If a man’s PSA level rises after prostate cancer treatment, his doctor will consider a number of factors before recommending further treatment. Additional treatment based on a single PSA test is not recommended. Instead, a rising trend in PSA level over time in combination with other findings, such as an abnormal result on imaging tests, may lead a man’s doctor to recommend further treatment.
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