PSA screening: Think twice before 'just getting it checked'

8/14/2017 by Dr. John Matulis


When we hear the word "cancer," our mind automatically jumps to a terrible, relentless disease that can be cured only if caught early. This was the general view of the medical community - at least until we started learning more about prostate cancer. 

In some men, prostate cancer can be very dangerous. However, most prostate cancers are slow-growing and not destined to cause any problems. The majority of men with this form of prostate cancer are said to die with it and not because of it. Unfortunately, determining whether a man has a "benign" or dangerous cancer is really difficult. Until one of the bad cancers is quite advanced, there usually are no symptoms to indicate that a man has the bad type. 

By screening men for prostate cancer we hope to catch the small number of these bad cancers, which if untreated, can shorten his life. 

It would seem like a simple Prostate Antigen (PSA) blood test to tell if someone does or doesn't have cancer is a no-brainer. Unfortunately, like many things in life, it isn't quite as simple as it sounds. Those dangerous cancers - the ones we really want to find and cure before they cause trouble - often develop very quickly. In fact, they can develop so quickly that the once-a-year blood test will miss up to two-thirds of them. 

It's not the fault of the test, since getting a normal test likely meant there was no cancer at that time. But the quick spread of bad prostate cancer means catching a fast-growing cancer at one point in time relies on a bit of luck. 

There are some things that are the fault of the test. There can be "false positive' results due to common conditions like prostate infection or aging-related prostate enlargement. The problem with these positive results is that they make it harder for doctors to determine whether the positive result is due to cancer or another cause. 

Most patients with a positive test then will have a biopsy. While a biopsy sometimes provides an answer, sometimes it doesn't. This cycle of testing, often without clear answers, can cause a lot of frustration and anxiety. Plus, the tests may cause complications or discomfort. 

These uncertainties make the decision to get a simple PSA blood test a complicated one. There isn't one answer that is right for everyone; men should take the time to learn all they can about the risks and benefits. Your health care provider's knowledge of your personal and family history, and individual preferences, should help lead you to a decision with which you are comfortable. 

Some sources for more information about prostate cancer and screen are the Centers for Disease Control and of course, Mayo Clinic

Dr. John Matulis is a Senior Associate Consultant in Employee and Community Health's (ECH) Division of Primary Care Internal Medicine (PCIM). In addition to general internal medicine, he is board certified in preventive medicine and has an interest in quality improvement.