On PSA Screening

Recently the U.S. Preventative Services Task Force has recommended against screening for prostate cancer with the PSA (Prostate Specific Antigen) blood test.The reason is that though the PSA has been shown to reduce prostate cancer mortality, it has not been shown to decrease overall mortality. How can this be? There is a saying in medicine that all men will die of prostate cancer, except that something else kills them first. This is because most prostate cancers are slow growing; and unfortunately, at this time we have no test, including the Gleason score which looks at prostate cancer cells under the microscope, that can tell us which cancers are going to become aggressive and quickly spread. Thus, no man after undergoing radical prostatectomy can know whether that surgery actually saved his life, even though his urologist will often assure him that it had. Moreover, the treatment of prostate cancer carries inherent risks, including death. The PSA screening program has allowed us to diagnose much more prostate cancer, and to “cure” those prostate cancers – the bulk of which would never have killed the patient; so the claim has been made that the PSA reduces prostate cancer mortality. But the number of people who die from hospitalization and treatment of prostate cancer cancels out the small number who were actually cured of a truly aggressive cancer, hence no decrease in overall mortality.

Hospitalization alone is dangerous, and then made riskier by procedures and surgery. Most people think of hospitals as places of rescue and safety, but hospital error is now considered to be the third leading cause of death in the U.S., behind heart disease and cancer. Most patients believe that more medical care is better, but that is usually not the case. To understand this phenomenon, I recommend the book “Overtreated: How too much medicine is making us sicker and poorer,” by Shannon Brownlee; it explains how we spend more that twice as much as most other industrialized countries on healthcare and yet get worse results. The over 18% of GOP that we spend on healthcare acts as a tax as insurance companies pass their costs on to employers, who then pay their employees less because they have to pay more to the health insurance firms. Yet the U.S. does no better in health outcomes, and usually does worse than other rich countries in average lifespan, infant mortality and maternal mortality. Unnecessary screening plays a large role in this equation, and I will discuss this further next month.

– Gary Gallo, MD