We’re told that researchers constructed a model – but there is no critical evaluation of that model.
PSA screenings are one of the most talked about and written about facets of cancer care. Readers – especially men in 40 and older – can be easily confused by what seem to be conflicting studies about the benefits and harms of PSA tests. After reading three stories about the study – TIME.com, HealthDay, and WebMD – you might feel satisfied that all the relevant ground was covered, and that the most compelling evidence would be given the proper weight. But in every story, there were deficits.
We reviewed three stories that covered this new retrospective study on PSA screening. None of them discussed the costs involved in the PSA tests or the subsequent treatments.
The story does accurately quantify the benefits of PSA screening as described in the study. It says, “In the 2008 data, 8,000 cases of prostate cancer were diagnosed after the malignancy had spread to other parts of the body. Using these cases as a base, the researchers constructed a model that used data of advanced cancer diagnosed in the 1980s and predicted how many cases of advanced cancer would have been diagnosed in 2008 if PSA testing was not done. Their model showed instead of 8,000 actual cases in 2008, about 25,000 cases would have been diagnosed.”
But there is no evaluation of the model itself. This is difficult stuff for a journalist to do – but if you’re going to report on such studies, you must. The TIME.com story at least took a stab at questioning the model. WebMD did better.
The story puts some hard numbers to the potential side effects, with help from Dr. Michael LeFevre, co-vice chair of the U.S. Preventive Services Task Force (USPSTF). The story says, “As a result of treatments for PSA-detected prostate cancer, one out of 1,000 men screened in the United States develops a blood clot in his legs or lungs, two will have a heart attack or stroke, and up to 40 are left impotent or with urinary incontinence, LeFevre said. ‘At best, only one of these 1,000 men who were screened avoids dying from prostate cancer for at least 10 years,’ LeFevre said. ‘In addition, about one in every 3,000 men screened dies as a result of surgery to treat cancer detected by the PSA test.’
The story did describe the study’s design and explained that the findings were statistical estimates. But it would be easy for a reader to misunderstand and assume that the study is proof that lives actually were saved as a result of the PSA. The story should have raised some of the same concerns about the study’s limitations that were raised in the TIME.com and WebMD stories.
HealthDay framed the discussion about PSA tests nicely by saying, “Many cases of prostate cancer are not life-threatening, which is why testing is controversial.” Contrast that with how TIME.com described the debate about whether to have a PSA test: “It depends on how much you value certain quality-of-life measures versus how much you value having any life at all.”
Expert perspectives from Dr. Otis Brawley of the American Cancer Society and from Dr. Michael LeFevre of the USPSTF helped this story.
The alternative to PSA screening is the choice to not be screened – and that is at the core of the story.
The story made it clear that PSA screening is widely available.
There were no claims of novelty in the story.
The story did not rely on a press release.