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Q. How can prostate cancer screening be a bad idea?
A. It might seem odd to think that undergoing a screening test could be a bad idea. But in recent years, we’ve recognized that screening—particularly for prostate cancer—can have some negative, often life-changing, consequences.
Now, some screening procedures inherently pose some level of risk. A screening colonoscopy, for example, can perforate the colon. The prostate-specific antigen or PSA test is not one of these, however. We screen for PSA via a blood test, so it poses no more risk than when you have blood drawn for any other reason.
Problems begin to arise when we are dealing with screening test has a high sensitivity, but low specificity.
In a diagnostic setting, sensitivity refers to a test’s ability to correctly identify those with the disease— the true positive rate. Test specificity, on the other hand, is the ability of the test to correctly identify those without the disease or the true negative rate.
The PSA test has a very high sensitivity, which means there are going to be very few false negatives. In other words, if I draw your blood and you have prostate cancer, we’re probably going to find it. But the same test has a very low specificity. That means that many people who don’t have the disease will often screen positive.
There’s a tremendous amount of anxiety that goes along with being told that you have an elevated PSA. I don’t care how tough you are; no individual can be nonchalant about receiving this news.
The anxiety is significant because, for some, it can be overwhelming. Patients are initially fearful, and often, depression can set in. A good doctor will warn someone about the potential for a false positive reading in advance and mitigate against undue psychological harm.
He or she will also express that an elevated PSA doesn’t necessarily mean that it’s prostate cancer and that it’s often the result of an infection, an enlarged prostate, or something else altogether. But even the best bedside manner isn’t going to offset how scary this information can seem. Anxiety then is the first way in which PSA screening can have negative consequences. But there are others.
If PSA levels remain elevated over several months and other possible causes are ruled out, the next step will either be a radiographic test and/or a prostate biopsy. A prostate biopsy is uncomfortable, to say the very least. But beyond being something nobody looks forward to, a small percentage of men will develop sepsis from a potentially lethal blood infection, in its wake.
After the anxiety of being told that you have an elevated PSA, and the discomfort and potential risks of a biopsy, comes the agonizing decision over what to do next if prostate cancer is present. In the 1980s and 1990s, we would almost always treat the disease. But in recent years, prostate cancer biopsies have been showing us that not every patient needs to be treated.
See, certain prostate biopsies look uglier than others, and this ugliness can be predictive of how the cancer will behave. If the biopsy reveals more normal-looking cells, the disease is more likely to remain relatively dormant, often for many years. By contrast, the less normal the biopsy looks, the more aggressive the cancer is likely to be.
Often, prostate cancer is not aggressive, and that allows us to take a “let’s see what happens” approach, which we refer to as active surveillance. Now, active surveillance does not mean ignore. In cases when the cancer does not appear to be aggressive, we would tell a patient: “you do have low-level prostate cancer. It’s very unlikely to kill you, but we do have to monitor you over the next four to six months and then periodically.”
But there are plenty of people for whom the “let’s see what happens” approach won’t work. Cancer, in general, is such a scary diagnosis that these men will want to be cured of it regardless of the consequences. The thing is, the outcomes of radiation therapy or radical prostatectomy, meaning the surgical removal of the prostate, are often severe. They can include erectile dysfunction, urinary incontinence, fecal incontinence, among others.
There are certain people for whom an elevated PSA has greater significance. In African American men, prostate cancer can be much more aggressive and develop at an earlier age, so an elevated PSA reading means more. The same can be said for men who have multiple first-degree relatives with prostate cancer. However, for older men and men with underlying medical issues, the number is often less significant because they may be more likely to succumb to something other than prostate cancer.
While we often talk about the relatively small percentage of people who die from the disease after being diagnosed with prostate cancer, it is the second biggest cancer killer of men after lung cancer. Our challenge is figuring out how to parse out men for whom treatment may be life-saving from men who will not die or be harmed from the disease. We’re getting better at doing that and can foresee medical advancements giving us additional clues about how prostate cancer is likely to behave.