Other than skin cancer, prostate cancer is the most common type of cancer in U.S. men. Early detection and improvements in therapy have resulted in a dramatic decrease in prostate cancer deaths (by 40 to 50 percent) since the early 1990s.
Screenings to detect prostate cancer early
One of the best ways to detect prostate cancer early is through screening — testing to find the disease in men with no prostate cancer symptoms.
Screening can help find some types of cancer at an early stage, when they may have a better prognosis. In fact, screening alone is credited for one-third of the recent decrease in prostate cancer deaths.
The two most common screening tests for prostate cancer are:
- Digital rectal exam (DRE)
- Prostate-specific antigen (PSA) test
Talk with your doctor about the benefits and risks of these screenings. Decisions should be based on:
- Your individual prostate cancer risk
- Your overall health and life expectancy
- Your desire for treatment if you are diagnosed with the disease
Digital rectal exam
For a DRE, a doctor inserts a gloved, lubricated finger into your rectum to:
- Feel your prostate gland.
- Assess the texture of the back of the gland, where most prostate cancers begin.
- Check for any bumps (nodules) or hard areas that might be cancer.
This exam usually isn’t painful and only takes a few seconds.
Since the PSA test was introduced in the late 1980s, doctors have commonly used it along with a DRE to screen for prostate cancer. Because the DRE can sometimes find cancers in men with normal PSA levels, Seattle Cancer Care Alliance (SCCA) recommends men 55 or older talk to their doctor about whether DRE is right for them. For some men, such as African-Americans or those with a family history of cancer, doctors may recommend screenings starting at an earlier age.
The PSA test is a blood test that measures a protein released in the blood by prostate cells. The higher a man’s total PSA level, the more likely he is to have prostate cancer. A few things to keep in mind about this test:
- Both normal and cancerous prostate cells secrete the protein.
- Elevated PSA levels are usually caused by noncancerous conditions, such as benign prostatic hyperplasia or prostatitis.
- Some men who have prostate cancer do not have elevated PSA.
While there is no perfect screening test for prostate cancer, a PSA test is the most common screening.
Most urologists consider these PSA levels to be normal:
- Men younger than 60 — total PSA of 2.5 ng/mL or lower
- Men 60 or older — total PSA of 4.0 ng/mL or lower
PSA screening risks and benefits
In recent years, PSA screening has come under fire because of concerns that it has led to overdiagnosis and overtreatment. At SCCA, we believe there are several good reasons to continue PSA screening.
Screening helps detect early-stage disease
PSA screening has yielded a dramatic transformation in how prostate cancer patients present — meaning, the status of their disease when they first get the diagnosis. More men begin care with early-stage and potentially curable disease.
Screening and treatment can be done selectively, based on a man's individual situation
PSA screening has likely saved many lives, but it also uncovers many cases of prostate cancer that may not need to be treated. The main harm in screening is not the PSA test itself but the possibility that the results may lead to overtreatment of low-risk cancers in older men.
Men who are younger and appear to be healthy are most likely to benefit from screening that leads to early detection and treatment. Some low-risk prostate cancers can be carefully followed with active surveillance rather than treated initially with the typical more aggressive measures.
Screening studies in the medical literature have limitations
Published screening studies have had limited follow-up and a lower death rate than expected in the absence of screening. What does this mean? The studies almost certainly understated the lives saved over the long term and produced an overly negative view of the benefits of screening. Also, almost all men in these studies who were assigned to the “no screening” group actually did have screening either before or during the study. Several more recent studies reveal greater benefits for healthier, younger men.
Most importantly, there is no doubt that prostate cancer deaths have decreased by about 40 percent since the advent of PSA screening, as shown in a National Cancer Institute investigation.1
DRE and PSA screening guidelines
SCCA’s prostate cancer specialists recommend the following:
- Men under 40 — DRE and PSA screenings are not recommended for men at average risk.
- Men 40 to 54 — DRE and PSA screenings are not recommended for men at average risk.
- Men 55 to 69 — DRE, PSA or both screenings may be right for you. Talk with your doctor about the risks and benefits.
- Men 70 or older — DRE and PSA screenings are generally not recommended, but older men who are in excellent health may benefit from screening.
Talk with your doctor about screenings if:
- You have any questions about whether DRE or PSA is right for you.
- You have risk factors, such as a family history of certain cancers or inherited genetic mutations that may increase risk.
SCCA prostate cancer doctors are well equipped to discuss the benefits and risks of screening and whether regular screenings are right for you.
Other screening tests
If your total PSA test results are high or abnormal, your doctor may use other screening tests to help determine if you need a biopsy, which is the only way to definitively diagnose prostate cancer.
A free-PSA test checks for the amount of PSA in your blood that is not bound to other proteins. This is a subset of your total PSA. The test is usually ordered only if your total PSA is elevated. It can help your doctor determine whether you need further diagnostic tests. Your free-PSA level is divided by your total PSA to get the percentage of free PSA. A result of less than 10 percent means you have a higher risk for prostate cancer. The lower the percentage, the higher the risk.
Prostate health index (PHI)
A PHI is a blood test to detect and predict the probability of prostate cancer. It uses two of your PSA subset values to create a cancer risk ratio that may help your doctors determine whether they should perform a biopsy. Studies of the accuracy of this test are ongoing.
Urinary PCA3 test
This is a urine test for proteins that are specific to prostate cancer. Unlike PSA, PCA3 is produced only by prostate cancer cells, and the level is not affected by your prostate size. This test can be used with total and free PSA tests to help determine whether you need a biopsy. It is not used as a stand-alone test, and it is used more often in men who’ve had a negative biopsy (meaning cancer was not detected) to determine whether another biopsy may be warranted.
This is a specialized magnetic resonance imaging (MRI) scan of your prostate to identify potentially suspicious areas that doctors can target at the time of your biopsy (a method called MRI-fusion biopsy). This test is used most often in men whose biopsy did not show cancer but whose PSA level is rising or raises persistent concern. It’s possible to have a normal MRI but still have prostate cancer, so doctors often perform standard biopsies even when MRI results appear normal.
Preventing prostate cancer
Doctors don’t know the exact cause of prostate cancer, and many prostate cancer risk factors cannot be controlled, so it is not possible to prevent the disease. However, there are some things you can do, such as eat a healthy diet and exercise, that might help lower your risk (and might help you deal with the disease if you do develop it). The section on diet and exercise for men with prostate cancer may also help those who do not have the disease.
Hormone therapy to prevent prostate cancer
In 2003, a study called the Prostate Cancer Prevention Trial showed that hormone therapy with finasteride (Proscar) reduced the risk of developing prostate cancer by 25 percent. Finasteride is approved to treat benign prostatic hyperplasia (noncancerous enlargement of the prostate). This study was the first to show that a drug could be used to prevent prostate cancer.
In 2010, a similar drug, dutasteride (Avodart), was also found to reduce the risk of prostate cancer in men at higher-than-average risk for the disease.
However, there are potential side effects, and men who developed prostate cancer while on these medications were slightly more likely to have higher-grade cancer. As a result, finasteride and dutasteride have not been approved by the U.S. Food and Drug Administration for cancer prevention.
1. Hans Lilja et al, “Prediction of Significant Prostate Cancer Diagnosed 20 to 30 Years Later with a Single Measure of Prostate-Specific Antigen at or Before Age 50,” Cancer 117 (2011): 1210-1219, doi: 10.1002/cncr.25568.