The earlier cancer is detected, the greater the chance that it can be treated successfully.
Prostate cancer can be detected early, before symptoms develop, with a digital rectal exam (DRE) and the prostate-specific antigen (PSA) blood test.
Digital Rectal Exam (DRE)
The digital rectal exam enables your doctor to feel anything abnormal in the posterior (rear) area of your prostate, where most prostate cancers develop. Wearing a lubricated glove, the doctor will gently insert a finger into your rectum and check for any lumps or other irregularities that might be signs of prostate cancer.
Prostate-Specific Antigen (PSA) Test
The PSA test was developed at Roswell Park in the 1970s and is now in use worldwide. It’s a way to detect prostate cancer in the early stages, when it can be treated most effectively. Since the test was first introduced, the cure rate for prostate cancer has increased from about 4 percent to 80 percent.
How does it work? PSA is a protein that’s made by the prostate gland. PSA levels in the blood increase when a man has prostate cancer, an infection, or a condition called benign prostatic hypertrophy (BPH) or benign prostatic enlargement (BPE), a condition that is not cancer. To perform the test, a small amount of blood is drawn from your arm and tested to determine the amount of PSA it contains.
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Who Should Get a PSA Test?
Not everyone should get a PSA test. Why? Because many men in this country are treated for low-risk prostate cancer that is discovered through the PSA test, even when it is unlikely that the disease will ever cause symptoms or lead to death. And treatment is associated with significant side effects, including impotence (inability to get an erection) and incontinence (inability to hold urine). So a PSA test is recommended only for men who might be at greater risk for dying of prostate cancer — for example, younger men with a family history of prostate cancer or African-American men.
To avoid the risks of over-treatment, Roswell Park follows the guidelines established by the National Comprehensive Cancer Network (NCCN). The NCCN brings together world-renowned experts from 30 of the nation’s top cancer centers to write guidelines that specify the best ways of preventing, detecting and treating cancer. The guidelines are updated at least every year, on the basis of the latest research.
Michael Kuettel, MD, PhD, MBA, Chair of Roswell Park's Department of Radiation Medicine, serves on the NCCN Prostate Cancer Panel.
The NCCN recommends that only men in these categories receive a PSA test for early detection of prostate cancer:
- If you are African-American, or if you have a father or brother who had prostate cancer — especially if they were younger than 60 at the time of diagnosis — or if you have undergone genetic screening that showed you have a genetic mutation (such as BRCA1, BRCA2, ATM, HOXB13, MLH1, MSH2 or MSH6), you and your doctor should have a discussion about whether you should begin early detection of prostate cancer at age 40 and continue to be tested regularly. If you have a family history of prostate cancer, you should talk with your doctor about beginning early-detection testing 10 years before the age of the earliest prostate cancer case in your family (for example, at age 35 if your father or brother received a prostate cancer diagnosis at age 45).
- If you do not fall into any of the groups above, you may consider beginning early detection with a baseline PSA test and digital rectal exam at age 45. The results of those tests will be used to compare with future tests. If your first PSA test shows a level of 1.0 ng/mL or higher (see below: "What Do the Numbers Mean?"), you should undergo follow-up testing every one to two years. If your first PSA test shows a level less than 1.0 ng/mL, you should have follow-up testing every two to four years.
- A PSA test is generally not recommended for men over the age of 75 unless they are very healthy and have a life expectancy of 10 years or more.
You should discuss the pros and cons of having a PSA test with your doctor. If you do receive a PSA test, your doctor will need to put the results in perspective with your age, how long you can be expected to live, your family medical history, your race and the results of any previous PSA tests.
What Do the Numbers Mean?
PSA levels are measured as a number of nanograms (units) in each milliliter of fluid tested. This is written as ng/mL.
- PSA level 2.5 ng/mL or lower: This is a normal PSA level for men under age 60, but in some cases, prostate cancer may still be present.
- PSA level between 2.5 and 4 ng/mL: This is a normal PSA level for most men.
- PSA level between 4 and 10 ng/mL: This indicates that prostate cancer might be present. At this level, there is about a 25% chance that you have prostate cancer.
- PSA level 10 ng/mL or above: There is a 50 percent chance that prostate cancer is present. The higher the PSA rises above 10 ng/mL, the greater the chance that you have prostate cancer.
Your doctor may also monitor your PSA velocity, or doubling time, which means recording your baseline PSA — the level at your very first PSA test — and seeing how fast the PSA level increases over time. Rapid increases in PSA readings can suggest cancer. If your PSA is slightly high, you and your doctor may decide to keep an eye on your levels on a regular basis to look for any change in the PSA velocity.
PSA levels can increase for reasons other than prostate cancer. These include aging, infection, difficulty urinating, the use of certain herbal supplements, or an enlarged prostate (not due to cancer). Some prostate glands naturally produce more PSA than others; for example, African-American men tend to have higher PSA levels than men of other races. Your PSA level also may increase after ejaculating, exercising vigorously, bicycling or drinking alcohol, so doctors advise men not to do any of these things for at least three days prior to a PSA exam.
The Role of PSA in Choosing the Best Treatment
If you have received a diagnosis of prostate cancer, your PSA levels can be used along with the results of other tests and physical exams and your tumor’s Gleason score to help determine which tests are needed for further evaluation and to decide on the best treatment plan. After treatment has begun, your PSA and other tests will be used to determine how well the treatment is working: The more successful the therapy, the lower the PSA.