When “Skyrocketing” Isn’t

The calls started coming in over the weekend: reporters asking about an upcoming study that found metastatic prostate cancer cases were on the rise, and pointing to recommendations from the United States Preventive Services Task Force (USPSTF) against screening using prostate specific antigen (PSA) as a potential reason.

The problem is, this study can’t support that claim. Here’s what Chief Medical Officer Otis W. Brawley, M.D. had to say.

“This study makes a dramatic claim about an issue all of us have been watching eagerly: namely, whether less PSA screening might lead to more advanced cancers. But the current analysis is far from adequate to answer that question sufficiently.

Otis W. Brawley, M.D.

“The way epidemiologists measure things like incidence and mortality is to study rates, the number of cases per a number of people (usually per 100,000) to look for trends. But this study, done by a group of urologists, didn’t do that. Rather than measure rates of metastatic disease, they looked at the number of cases. That is far from the same thing.

“Epidemiologists learned long ago that you can’t simply look at raw numbers. A rising number of cases can be due simply to a growing and aging population among other factors. In addition, in this study, the rise they detected began before USPSTF guidelines for screening changed. There may or may not be a rise in the rates of metastatic disease; but because of a flawed analysis, this study does not answer that important question.

“So why was this unusual study leading to calls? It’s a safe guess that a press release sent to reporters nationwide with a somewhat alarming headline was the reason.

 

 

“The issue of whether and how screening may affect deaths from prostate cancer in the U.S. is an incredibly important one. This study and its promotion get us no closer to the answer, and in fact cloud the waters. We hope reporters understand that and use this study to ask another important question: can we allow ourselves to be seriously misled by active promotion of flawed data on important health matters?”

To read more about prostate cancer screening, see Finding Prostate Cancer Early on cancer.org.