By Michael R. Forrest, MD, Radiation Oncologist
Screening refers to the use of simple tests across a healthy population in order to identify individuals who have disease, but do not yet have symptoms. Prostate cancer screening for men involves checking Prostate Specific Antigen (PSA) in blood and a digital rectal examination.
PSA is produced by the normal glandular cells in the prostate gland. However prostate cancer cells usually make PSA in larger amounts. Elevated PSA in the blood does not always translate into presence of prostate cancer.
Unlike guidelines for early detection of other cancers like breast, colon and cervical cancers, research has not yet proven that the potential benefits of PSA screening outweigh the harm of treatment in patients with prostate cancer. Like any other screening test, PSA testing can be falsely positive or falsely negative.
False positive elevation of PSA indicates you might have prostate cancer when you don’t. This includes age related changes like Benign Prostatic hyperplasia (BPH) or infections of the prostate, among other causes. False-positives are common. Only about 1 in 4 men with an elevated PSA turn out to have prostate cancer.
False Negative Normal PSA indicates that your PSA is normal but you still have prostate cancer. This can happen in rare very aggressive prostate cancers, which do not produce the protein PSA in the blood.
Pros of PSA testing
It is a blood test and non-invasive, which your primary care physician can easily order and most insurance will cover. It may help detect prostate cancer early and increase your chance of cure. A normal PSA in most cases is reassuring to the patient.
Cons of PSA testing
Unlike other cancers, there is a significant variability in the behavior of prostate cancer. Some men will have “aggressive” or fast growing cancers that if not treated will lead to symptoms and death from prostate cancer. Other men have “non-aggressive” or slowly growing cancers, which will not affect them in their lifetime. It is inherent that as we diagnose more prostate cancer we will detect both non-aggressive and aggressive cancers.
Detecting a non-aggressive cancer will invoke considerable anxiety and exposure to treatment and its side effects including urinary incontinence, erectile dysfunction or bowel dysfunction. Also it is not very clear whether the decrease in deaths from prostate cancer are due to early detection and treatment based on PSA testing or from other factors. The key here is to be able to identify those prostate cancers that are aggressive and need intervention. A test of that nature is not yet available.
The National Comprehensive Cancer Network guidelines recommend that physicians do a baseline evaluation, do the risk assessment and then pursue further workup based on your family history, PSA levels and ethnicity.
The American Cancer Society similarly recommends that men make an informed decision with their doctor about being tested for prostate cancer. Starting at age 50, men should talk to a doctor about the pros and cons of testing so they can decide if testing is the right choice for them. If they are African American or have a father or brother who had prostate cancer before age 65, men should have this talk with a doctor starting at age 45.
A discussion with your physician addressing the above factors is therefore important to help you decide whether you should be screened for prostate cancer or not.
Dr. Forrest is a Radiation Oncologist with Epic Care, a group of experts in the diagnosis and comprehensive treatment of cancer and blood disorders. www.epic-care.com