Thursday, December 3, 2009

Healthy skepticism and improving health communication

In yesterday morning's hearing before the House of Representatives Energy and Commerce subcommittee on health, Dr. Ned Calonge and Dr. Diana Petitti, Chair and Vice Chair of the U.S. Preventive Services Task Force, admitted to a "failure in communication" of the Task Force's recently updated recommendations on breast cancer screening when it came to women ages 40 to 49 years. There was, and remains, absolutely nothing wrong with the science of the recommendations, which included advising against clinicians teaching self-breast examinations due to a lack of benefits (a conclusion also reached by the highly respected Cochrane Collaboration more than two years ago) and having mammograms performed every two years rather than every year, as is common practice in the U.S.

In an attempt to correct the widespread perception that the USPSTF had recommended against ALL women under the age of 50 having mammograms for screening purposes, the breast cancer screening page on the USPSTF website now includes a direct quotation from Dr. Petitti: "So, what does this mean if you are a woman in your 40s? You should talk to your doctor and make an informed decision about whether a mammography is right for you based on your family history, general health, and personal values." Although adding this quotation was too late to quell the political firestorm that erupted in the wake of the new recommendation (which was only pushed out of the headlines by the debate over appropriate troop levels in the war in Afghanistan), it is an attempt to translate what had been a statement directed at clinicians for patients and their caregivers.

In an earlier post on this blog, I mentioned how researchers at the Dartmouth Institute of Health Policy and Clinical Practice had developed a book meant to assist patients with understanding health statistics and using data to estimate their personal risk of contracting a disease or experiencing a disease-related event. In an editorial in this week's Journal of the National Cancer Institute, Dr. Woloshin and Dr. Schwartz (writing prior to the release of the USPSTF breast cancer screening recommendations) argue that while headline-seeking journalists are to blame for some of the exaggeration of health risks and benefits, researchers, medical journals, and academic press offices are also responsible for this common phenomenon:

Important elements that journalists (and, really, all readers) need are sometimes missing or hard to find in the published articles. For example, in six high-profile journals, two-thirds of articles reporting ratio measures failed to provide the underlying absolute risks in the abstract. ... Nor are study limitations routinely highlighted in journal abstracts ... and sometimes are missing from articles altogether. ... Only half of the press releases reporting on differences between study groups provided absolute risks; less than one-quarter noted any study limitation. ... Can we really expect journalists to do a better job than the medical journals, researchers, or their university public relations offices?

Studies have shown that women consistently overestimate their personal risk of breast cancer diagnosis, breast cancer death, and the benefits obtained from screening mammography. For the record, a typical 40 year-old woman has 1.4% chance of being diagnosed with breast cancer over the next 10 years, and a 0.33% chance of dying from it (or 1 in 300). Regular screening mammograms reduce the probability of dying of breast cancer in a 40 year-old woman by 0.05%, to 0.28% (or 1 in 357), at the cost of a 1 in 3 chance of experiencing a false alarm due to screening. Whether or not the cost is worth the benefit lies in the eye of the beholder - which is why, despite all of the unnecessary hysteria, the USPSTF got it right.