The United States Preventative Services Task Force (USPSTF) recently unleashed a controversy when it issued a draft recommendation advising healthy men to stop receiving routine blood tests for prostate-specific antigen (PSA).
PSA is a protein secreted by prostate cells, and elevated blood levels of the chemical often signal cancerous cell growth in the prostate gland. The Task Force’s announcement comes as a result of two large-scale studies published in 2009, both of which found that routine PSA testing in large groups offers little to no benefit in terms of total lives saved.
In approaching the PSA debate, one must first have an understanding of the realities of prostate cancer itself. We tend to think of cancer as a monolith, and we assume that the dark cloud, once noticed, marches unchecked unless kept away with medical intervention. Cancers are extremely diverse, however, and the kind which strikes the prostate tends to be unusual. Prostate cancer is likely to remain indolent, smoldering until the carrier dies of some other cause. While the disease is quite prevalent — a man has about a 16% lifetime chance of receiving a diagnosis — only a fraction of these cancers will ever cause any significant harm. A man has a 3% lifetime chance of dying from the disease.
The central problem in prostate cancer is that it is difficult to tell which cancers will remain sluggish and which will progress dangerously. There are testing techniques that seek to determine the virility of an individual’s cancer, but they are prone to error. A man can never be certain that his cancer’s risk has been correctly assessed. Given the prognostic imperfections, it is no surprise that roughly 90% of men who receive bad news from a PSA test will wind up undergoing aggressive treatment, usually in the form of surgery or radiation.
The treatments themselves, however, carry considerable consequences. Among the roughly one million men who received treatment as a result of PSA testing between 1986 and 2005, an estimated 5,000 died soon after the procedure. Another 10,000 to 70,000 suffered serious complications, and 200,000 to 300,000 were left impotent, incontinent, or both.
That said, prostate cancer deaths did decline during this period, as noted in a recent PolicyMic article. Early detection may well account for some of this reduction, but the effect is uncertain. As Columbia University medical professor Barron H. Lerner recently wrote, the genetic characteristics of a given cancer are more important than the time of detection in determining survival. Regardless, if we are to be generous and credit early detection for every death averted during this period, the calculus is still daunting: For each of the estimated 56,500 lives saved, between 20 and 50 men had to be unnecessarily treated.
The data provide a reasonable argument against PSA screening. The test’s impact on overall mortality is minimal at best. Screening leads many down a path of needless and often damaging procedures. The problem, however, is that there is a fundamental disconnect between population level realities and the personal choices that must be made in the doctor’s office. A man offered the chance to know if he has a cancer growing inside of him is hard-pressed to analyze the situation with the cold math of the epidemiologist. Once an elevated PSA has been found, avoiding action becomes even harder. Cancer menaces and leaves a bold imprint on our minds, but treatment complications are in the fine print: They are an afterthought, freak occurrences that happen to other people, not us. Although the odds are decent that a man who develops prostate cancer will never experience any trouble from it, the possibility of being in the unlucky minority produces understandable terror. Public testimonials from prostate cancer survivors further emotionalize the issue, putting a courageous face on the cause of early detection and treatment. The countless men who have suffered from unnecessary treatment, however, remain in the shadows. All of the forces at play — family, physician, culture — line up in the direction of testing and treatment.
What is the answer here? As with so many health issues, the decision ultimately comes down to the patient. Health insurers could choose to stop paying for the test, but, given the current outcry over the USPSTF recommendation, the short-term odds of this seem remote. Doctors and patients must focus on increasing understanding and transparency in the prostate screening process. Before being tested, patients must be made aware of the limitations of the test, the real meaning of a diagnosis, and the potential risks of intervention. Whichever decision is made — to test or not to test — there are dangers on either side. No amount of data or knowledge can alleviate the human difficulty of making such a complex health decision. We can only hope that the USPSTF’s recommendation will prompt more men and their doctors to approach this weighty matter with caution.