A well-known research university and some excitable journalists have sown confusion about prostate cancer and the value of the PSA screening test. The mess can be traced to a study by physicians from Northwestern University and the University of Chicago, and published in the journal Prostate Cancer and Prostatic Disease. Their article reports an “increase” in one of the most aggressive forms of the disease, metastatic prostate cancer, and suggests it might be caused by less use of the PSA blood test.
Northwestern’s PR machine hyped the study, saying that “Metastatic prostate cancer cases skyrocket.” NU’s news release—which was picked up by all too many media outlets (the Times shames them in visual fashion atop its story)—also tied this to “lax screening.” That was an allusion to recommendations by a blue-chip national panel that has advised against routine prostate cancer screening using the prostate-specific antigen (PSA) test. The group said the screenings often resulted in false alarm “false positive” results, leading to invasive, harmful, unnecessary, and costly follow-on procedures.
As the online watchdog site HealthNewsReview.org points out, the Northwestern researcher author is a PSA testing proponent, a “true believer.” The site, as well as experts from the American Cancer Society and others, have debunked the study, saying it fails to demonstrate either that this form of prostate cancer has “skyrocketed” or that there is a proven link to reduced PSA screening.
In unusually pointed language, the cancer society’s chief medical officer told the New York Times that the Northwestern-Chicago study was “misguided epidemiology,” and said its authors “don’t know what they don’t know.” On its website, the cancer society also posted details why the study is flawed: the researchers, wrongly, relied on raw case numbers. As the Times explains:
The doctors examined the records of 767,550 men with prostate cancer diagnosed from 2004 to 2013. Using the number of cases of metastatic disease in 2004 (1,685) and 2013 (2,890), they reported an alarming increase of 72 percent. But for the United States population, that percentage could be meaningless.
Put it another way: the hubbub that this study caused was based on 1,205 cases over a nine-year period in a U.S. population of roughly 90 million men, ages 20 to 79. If you want to scratch your head about the claimed link to reduced PSA screening, also consider that the influential U.S. Preventive Services Task Force also did not issue its expert recommendation against this testing until 2012.
As I have written, evidence-based medicine must become the gold-standard if this nation is to reduce its costs, increase the access, and improve the quality and safety of care offered to Americans. Experts have applied more rigorous methods, and, have moved─correctly─to offer sounder guidance about the reflexively administered PSA test, annual physicals, regular mammograms for all women, and frequent pelvic exams for health women. Preventive tests and procedures that benefit health outcomes merit support; we need to ease back on those that can lead to greater harm.
