Thursday, January 26, 2006
A substantial disagreement in management recommendations -- in which one radiologist recommended routine follow-up and another recommended a biopsy for the same patient -- occurred in 3 percent of the pairwise comparisons but in 25 percent of the comparisons for the group of women as a whole. When two or more radiologists recommended a biopsy for the same patient, a disagreement in the stated location (right or left breast) occurred in 2 percent of the pairwise comparisons among the radiologists but in 9 percent of comparisons for the group of women as a whole. Because some disagreement was likely, given that 10 radiologists read each film, the pairwise comparison is a more conservative estimate of disagreement.
No matter how you slice it, that guy in England was doing a better than average job.
As a letter to the editor written in response to the above study noted, mammograms are not 100% accurate. They are a screening tool, meant to enhance our probability of detecting something, not a diagnostic tool:
The findings of Elmore et al. attest to the subjectivity and gross nature of mammographic findings. Considering that pathologists struggle with an accurate diagnosis even at more than 100 times the magnification of a mammogram, it is highly unlikely that greater accuracy in mammographic diagnosis will ever be achieved with current techniques. Unfortunately, the news media, having previously misled the public by overemphasizing the diagnostic potential of mammograms, are now heightening the apprehension of an already anxious population. The latest hoopla will stimulate the call for expensive second and third radiologic opinions and deflect attention from a vital point that is made in the editorial by Kopans. Mammography is an effective screening technique but not an accurate diagnostic technique. The essential purpose of a mammogram is only to demonstrate an important abnormality at the earliest possible time. A definitive pathologic diagnosis is to be expected in a very small proportion of cases.
Although the radiologists who participated in the study by Elmore et al. were made aware of the clinical findings, they obviously could not examine the patients but were requested to suggest a plan of management. Readers must not come away from this article with the mistaken impression that an appropriate plan of management can be devised solely on the basis of a mammogram. The mammogram complements the history and physical examination. The physician who is primarily responsible for the care of the patient is the one who makes the essential management decisions.
Here is what a mammogram looks like. You can see what radiologists are up against.
According to the original news story, the response in England to the 1% error rate of this radiologist is to advocate for two radiologists to read each film. As the above study shows, that probably won't solve the problem, even if they can find two radiologists to read each film:
"The acute U.K.-wide shortage of radiologists must be addressed to ensure reliable breast screening for all," Clara McKay of charity Breast Cancer Care told the newspaper.
posted by Sydney on 1/26/2006 07:08:00 AM 4 comments
totally agreed, mammography is a study with limitations and not all cancers are seen on a mammogram...
Sumer, maybe if you stop giving inflated mortality reduction numbers in you blog and start telling public the truth about both expected benefit (in absolute not relative numbers) and risks (for some reason I missed any mention of overdiagnosis in your website), public will not expect that much from you?
By 11:43 AM, at
Oops, sorry (from the same anonymous) - I just realized you just quoted an article that listed these inflated numbers. I should read more carefully next time.
By 10:23 PM, at
» International Trial Of Novel Breast Cancer Drug