PSA - Early Detection - Screening - Prevention of Prostate Cancer
Medically reviewed by Dr C.H. Weaver M.D. 6/2019
One man in six will develop prostate cancer
There are no symptoms for early-stage prostate cancer, but it can be detected through screening. The term screening refers to the regular use of certain examinations or tests in persons who do not have any symptoms of a cancer but are at risk for that cancer. When individuals are at high risk for a type of cancer, this means that they have certain characteristics or exposures, called risk factors, that make them more likely to develop that type of cancer than those who do not have these risk factors. (1,2,3,
The American Urological Association says men should have their first screening for prostate cancer at age 40. Usually doctors recommend that men repeat the screening annually, but depending on your unique risk factors, your doctor may suggest a different screening schedule. A screening exam consists of a digital rectal exam (DRE) and a blood prostate-specific antigen test (PSA)
Digital Rectal Exam: A physician inserts a gloved finger into the rectum to assess the texture and size of the prostate. The DRE is the most common prostate screening procedure and has been used for many years; however, whether the test is effective in decreasing the number of deaths from prostate cancer has yet to be determined.
PSA Blood 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 of PSA normally enters the bloodstream. Prostate cancer cells usually make more PSA than do benign cells, causing PSA levels in your blood to rise. But PSA levels can also be elevated in men with enlarged or inflamed prostate glands. Therefore, 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
About BRCA: Inherited mutations in two genes—BRCA1 and BRCA2—have been found to greatly increase the lifetime risk of developing breast, ovarian, and now prostate cancer. Mutations in these genes can be passed down through either the mother’s or the father’s side of the family.
The BRCA1 and 2 genes, have been linked to an increased risk of developing breast and ovarian cancer for several years. Women with BRCA have their risk of developing cancer managed aggressively with increased screening and occasionally preventative surgery.
The BRCA gene is thought to be present in about 5% of men, and these men have an increased risk prostate specific antigen) testing to help detect the disease earlier.
Researchers have found that men who carry the BRCA2 genetic mutation are almost twice as likely to be diagnosed with prostate cancer than those without the mutation and men with BRCA2 have more serious cancers. The BRCA2 defect increases the risk of prostate cancer in men and shows that a better test is needed to diagnose them.
Men may get tested for BRCA due to a family history of breast cancer, as they could pass the gene onto their daughters, there is no prevention pathway currently in place for men to find out they’re a carrier for BRCA. It may be that men who carry the BRCA2 gene should undergo earlier and more regular PSA testing so that they can be diagnosed and treated earlier.
Should You Get a PSA Test?
Cancer screening tests—including the prostate-specific antigen (PSA) test—can be a good idea. Prostate cancer screening can help identify cancer early on, when treatment is most effective. And a normal PSA test, combined with a digital rectal exam, can help reassure you that it’s unlikely you have prostate cancer. But getting a PSA test for prostate cancer may not be necessary for some men, especially men 75 and older.
Professional organizations vary in their recommendations about which men should get a PSA screening test. While some have definitive guidelines, others leave the decision up to men and their doctors. Organizations that do recommend PSA screening generally encourage the test in men between the ages of 40 and 75 and in men with an increased risk of prostate cancer.
Ultimately, whether you have a PSA test is something you should decide after discussing it with your doctor, considering your risk factors, and weighing your personal preferences.
A Simple Test, A Not-so-simple Decision: Pros and Cons of PSA Screening
Pros of PSA Screening
- PSA screening may help you detect prostate cancer early.
- Cancer is easier to treat and is more likely to be cured if treated early.
- PSA testing can be done with a simple, widely available blood test.
- For some men, knowing is better than not knowing. Having the test can provide you with a certain amount of reassurance (either that you probably don’t have prostate cancer or that you do have it and can now have it treated).
- The number of deaths from prostate cancer has gone down since PSA testing became available.
Cons of PSA Screening
- Some prostate cancers are slow growing and never spread beyond the prostate gland, meaning that they would not require treatment.
- Not all prostate cancers need treatment. Treatment for prostate cancer may have risks and side effects, including urinary incontinence, erectile dysfunction, or bowel dysfunction.
- PSA tests aren’t foolproof. It’s possible for your PSA levels to be elevated when cancer isn’t present, and to not be elevated when cancer is present.
- A diagnosis of prostate cancer can provoke anxiety and confusion. Concern that the cancer may not be life-threatening can make decision making complicated.
- It’s not yet clear whether the decrease in deaths from prostate cancer is due to early detection and treatment based on PSA testing or due to other factors.
When an Elevated PSA Isn’t Cancer
While high PSA levels can be a sign of prostate cancer, a number of conditions other than prostate cancer 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 with a positive PSA test actually has prostate cancer.
7 common things that can affect your PSA level
Older men’s normal PSA levels run a little higher than those of younger men. Normal levels tend to vary a little between different ethnic groups, but in general…
2. Prostate size
Because PSA is naturally produced at a very low level by the healthy prostate, a man with a larger-than-usual prostate may have a higher-than-usual PSA level. Your doctor will be able to detect this with a DRE, and will take this into consideration when looking at your PSA test results.
Prostatitis is a painful condition in which the prostate is inflamed, swollen, and tender. It can be caused by a bacterial infection or just simply be inflamed. In some cases, an elevated PSA level may be another effect of this illness.
4. Benign prostatic hyperplasia (BPH)
Different from simply having a larger-than-usual prostate, BPH is an enlarged prostate. It’s somewhat common among men over 50, and it may make urination or ejaculation difficult, which could send you to the doctor to have it checked. Along with the swelling, a prostate with BPH may produce more PSA than usual. Your doctor may recommend additional tests to confirm BPH.
5. Urinary tract infection or irritation
An infection of the urinary tract, as well as irritation caused by medical procedures involving the urethra or bladder, may irritate the prostate and cause it to produce more PSA. If you have experienced any of these, be sure to let your doctor know. You’ll need to give the area some time to heal and calm down before running a PSA test.
6. Prostate stimulation
Any prostate stimulation can trigger the release of extra PSA. This can include some sexual activity, including ejaculation, but even having a DRE can raise PSA levels. For this reason, doctors usually draw blood before performing the DRE to avoid affecting the PSA test results.
Some medications can artificially lower the PSA, such as finasteride (Proscar or Propecia) or dutasteride (Avodart). Be sure to remind your doctor of any and all medications you may be taking, so they can factor them in when assessing your PSA test results. (8)
PSA levels can fluctuate, and they can be influenced by a number of different factors. Your normal PSA levels might just be a little higher than most men in your demographic category. The important thing is to be able to freely talk over the possible factors so that your doctor can realistically assess your scores and you can monitor them over time.
- Statins May Reduce PSA Levels
The use of cholesterol-lowering drugs known as statins is associated with a decline in prostate specific antigen (PSA) levels. (4,5) Furthermore, some evidence has linked statins with the prevention of cancer, including a Finnish study that reported a 50-65% reduction in prostate cancer risk among statin users versus non-users. Researchers from Duke University also reported a 4.1% average PSA decline and a 27.5% average LDL decline. Men with higher initial PSA levels had larger declines after beginning statin therapy than men with low initial PSA levels. Furthermore, the PSA decline appeared to be correlated with the magnitude of LDL decrease. In other words, the more the LDL declined, the more the PSA declined. The questions left unanswered by these studies are whether statins might prevent prostate cancer, treat prostate cancer, or simply affect PSA levels alone.
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, or 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 to have a doctor who is experienced in interpreting PSA levels evaluate your situation.
What’s the Advantage of a PSA Test?
Detecting certain types of prostate cancer early can be critical. Elevated PSA results may reveal prostate cancer that’s likely to spread to other parts of your body (metastasize), or they may reveal a quick-growing cancer that’s likely to cause other problems.
Early treatment can help catch the cancer before it becomes life-threatening or causes serious symptoms. In some cases, identifying cancer early means you will need less aggressive treatment, thereby reducing your risk of certain side effects, such as erectile dysfunction and incontinence.
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 simply requires 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
Think about Your Risk Factors for Prostate Cancer
Knowing the risk factors for prostate cancer can help you determine if and when you want to begin prostate cancer screening. The main risk factors include:
- Age: As you age, your risk for prostate cancer increases. After age 50, your chance of having prostate cancer increases substantially. The majority of prostate cancers are found in men age 65 or older. The option to have PSA testing begins at age 40 and continues until you’re at the age when your life expectancy is 10 years or fewer. Once you reach that age, the likelihood that a prostate cancer would progress and cause problems during the remainder of your lifetime is small. ()
- Race: For reasons that aren’t well understood, black men have a higher risk of developing and dying of prostate cancer.
- Family history: If a close family member (your father or brother) was diagnosed with prostate cancer before age 65, your risk of the disease is greater than that of the average American man. If several of your first-degree relatives (father, brothers, sons) have had prostate cancer at an early age, your risk is considered very high. Researchers have estimated that approximately 9 percent of prostate cancers may be the result of heritable susceptibility genes. Approximately 15 percent of men with prostate cancer have a first-degree male relative (father or brother) with prostate cancer, compared with 8 percent of the general population.
- Diet: A high-fat diet and obesity may increase your risk of prostate cancer.
- Hormones: Some research indicates that high testosterone levels may increase the risk of prostate cancer.
How often should PSA testing be performed? Consider the varying recommendations?
American Urological Association (AUA)
- The AUA recommends that doctors offer a baseline PSA test to men who wish to be screened at age 40. It also encourages men who expect to live at least another 10 years to discuss the risks and benefits of PSA testing with their doctors.
American Cancer Society (ACS)
- The ACS recommends that men consult with their doctors to make a decision about PSA testing. According to the ACS, men should explore the risks and benefits of the PSA test starting at age 50 if they are at average risk of prostate cancer, at age 45 if they are at high risk and at age 40 if they are at very high risk (those with several first-degree relatives who had prostate cancer at an early age).
Centers for Disease Control and Prevention (CDC)
- The CDC recommends against PSA-based screening for men who do not have symptoms, but supports discussions between men and their doctors to make informed decisions about screening based on individual risks and preferences.
U.S. Preventive Services Task Force (USPSTF)
- The USPSTF recommends against PSA-based screening, regardless of age. The USPSTF states that there is moderate to high certainty that PSA testing has no net benefit or that harms outweigh benefits.
American College of Preventive Medicine (ACPM)
- The ACPM recommends that a man decide about whether to have PSA testing after discussing the risks and benefits with his doctor. The ACPM considers the need for screening questionable in older men with other chronic illnesses and men with life expectancies of fewer than 10 years.
With a positive PSA, when should a prostate biopsy be performed?
According to research published in the Journal of the American Medical Association (JAMA), there is no defined PSA level that provides both acceptable sensitivity and specificity in the detection of prostate cancer.
Historically, a PSA level of 4.0 ng/ml in the blood was the cut-off level used to determine when a man would undergo a prostate biopsy to establish whether cancer actually existed. However, recent studies have indicated that a cut-off of 2.5 or 2.6 ng/ml is a more effective level from which to proceed to a biopsy. Studies using this cutoff level resulted in the detection of significantly more cases of prostate cancer, while rates of unnecessary biopsies remained acceptable. Unnecessary biopsies should be kept to a minimum since they are associated with increased medical costs, time commitments for patients and the medical system, pain, anxiety and possible infection. The optimal PSA level that provides both acceptable sensitivity (detection of prostate cancer) as well as specificity (discerning between cancerous and non-cancerous conditions) is currently under debate.
It is important for patients to speak with their physician regarding their individual risks and benefits of undergoing prostate biopsies according to specific PSA levels. (7)
- Efstathiou J, et al. Evidence to Support that Serial Screening Decreases Prostate Cancer-Specific Mortality. Proceedings from the 47th annual meeting of the American Society of Therapeutic Radiation Oncology (ASTRO). October, 2005. Denver, Colorado. Abstract #185.
- Hamilton RJ, Goldberg KC, Platz EA. The influence of statin medications on prostate-specific antigen levels. Journal of the National Cancer Institute. 2008;100:1511-1518.
- Murtola TJ, Tammela TLJ, Maattanen L. Statins and prostate cancer among men participating in the Finnish Prostate Cancer Screening Trial. American Urological Association Meeting, Anaheim, California; 2007. Abstract 1719. .
- Crawford D, Chia D, Andriole G, et al. PSA testing interval reduction in screening intervals: data from the prostate, lung, colorectal and ovarian cancer (PLCO) screening trial.
- Thompson I, Ankerst D, Chi C, et al. Operating characteristics of prostate-specific antigen in men with an initial PSA level of 3.0 ng/mL or lower. *Journal of the American Medical Association.*2005;294:66-70.
- D’Amico AV, Roehrborn C. Effect of 1 mg/day Finasteride on Concentration of Serum Prostate-specific Antigen in Men with Androgenic Alopecia: A Randomized Controlled Trial. Lancet Oncology [early online publication]. December 5, 2006.
- Mäkinen T, Teuvon T, Tammela LJ, et al. Family History and Prostate Cancer Screening With Prostate-Specific Antigen. Journal of Clinical Oncology. 2002;20:2658-2663.
- Crawford D, Chia D, Andriole G, et al. PSA testing interval reduction in screening intervals: data from the prostate, lung, colorectal and ovarian cancer (PLCO) screening trial. Proceedings from the 38th Annual Meeting of the American Society of Clinical Oncology. 2002;21 (Abstract 4).