covering screening tests: do no harm (as a reporter)
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One of two talks I gave at Cancer Research in the Media: The NCI’s 2nd Annual Inter-American Workshop for Scientific JournalismTRANSCRIPT
Covering Screening Tests: Do No Harm (as a Reporter)
Ivan Oransky, MDExecutive Editor, Reuters Health
Cancer Research in the MediaInter-American Workshop for Scientific Journalism
Guadalajara, MexicoNovember 7, 2011
What’s Not Worth Covering
What’s Worth Covering?• Focus on evidence, not opinion, advocacy, or
anecdote• Criteria: Peer-reviewed?
Most journals areMost conferences aren’t
What’s Worth Covering?
What’s Worth Covering?• Conferences select presenters based on < 1000 words
• Urologists at U of Florida & Indiana U studied 126 randomized controlled trials presented in 2002-2003
What’s Worth Covering?• RCTs are the “gold standard” of medical evidence
• But the quality of that evidence wasn’t pretty
• No abstract said how trial subjects were randomly assigned to different treatments or placebos
• None told how the study ensured that neither the researchers nor their doctors knew which they got
• Only about a quarter said how long researchers followed the subjects in the trial
What’s Worth Covering?• Published?
In what kind of journal?How highly ranked (e.g., what impact factor)?
• Just because it’s in a journal doesn’t mean it’s the highest-level of evidence
From Covering Medical Research, Schwitzer/AHCJ
Journals: What to Keep in Mind• Positive publication bias:
Publish a trial that will bring US$100,000 of profit or meet the end-of-year budget by firing an editor. -- Former BMJ editor Richard Smith
• Over-reliance on embargoed studies
• How often it turns out to be wrong
Journals: What to Keep in Mind
Ioannidis JPA. PLoS Med 2005; 2(8): e124
Journals: What to Keep in Mind
Always Read the StudyWriting about a study after reading just a press
release or an abstract – without reading the entire paper –
is journalistic malpractice
How to Get Studies• www.EurekAlert.org for embargoed material
• Join the Association of Health Care Journalists – membership includes access to Cochrane Library, Health Affairs, JAMA, and many other journals www.healthjournalism.org
• ScienceDirect (Elsevier) gives reporters free access to hundreds of journals www.sciencedirect.com
• Open access journals (e.g., Public Library of Science www.plos.org)
• Ask press officers, or the authors
A Dirty Little Secret
Keep a biostatistician in your back pocket
Photo by Peyri Herrera, on Flickr
How to Cover Screening• Early detection is only worthwhile if two
conditions are met:– the disease tends to kill people (not all do)– there are effective treatments that people are
willing to have
• Keep lead time bias in mind
• Be wary of “pre-cancerous” conditions
• Remember: Screening tests have harms
Testing vs Screening• If someone is part of a risk group, that’s testing,
not screening
• Screening refers to testing large populations without any clear increased risk
Are There Alternatives?• Colonoscopy vs. sigmoidoscopy vs. fecal occult
blood testing
• Digital mammography vs. film mammography
•
Brownlee S, Lenzer J. The New York Times, 10/5/2011
What If You Test Positive?• Is there a good treatment?
• What are side effects and costs of treatment?
What Do Guidelines Say?• USPSTF
http://www.uspreventiveservicestaskforce.org
What Do Guidelines Say?• Cochrane Library http://www.cochrane.org/
What Do Guidelines Say?• Cochrane Library http://www.cochrane.org/
• Scientific and medical societies
Who Gains from Promoting Screening?
• Doctors, hospitals• Drug and device manufacturers• Advocacy groups– More worry, more funding
Are you engaging in disease mongering?
Number Needed to Screen• An elegant way to help decide whether
something is worthwhile
• Example:
To find one dangerous breast cancer, you’d need to screen 1,900 women between 40 and 50, compared to 1,300 women over 50.
So how many false positives, biopsies, overdiagnosed/overtreated women would result?
Number Needed to Screen“Most women with screen-detected breast cancer have not had their life saved by screening. They are instead either diagnosed early (with no effect on their mortality) or overdiagnosed.”
