Risk of False Alarm for Breast Cancer
Frederick R. Jelovsek
If you are a woman who gets a mammogram on a fairly regular
basis, what is the chance that you will have a distressing
false alarm? In other words, what is the chance that you will
get a notice or call from your doctor asking you to have some
more studies because the mammogram or the breast exam was not
entirely normal?
In a recent study, Elmore JG et al: Ten-year risk of false
positive screening mammograms and clinical breast examinations.
N Engl J Med 1998; 338:1089-96., the investigators
studied 2400 women ages 40-69 who had a total of 9762 screening
mammograms and 10905 screening breast clinical physical exams
over a 10 year period. This averaged 4 mammograms and 5 clinical
breast exams during the study time.
Of the women screened, one third had abnormal testing results
that required further evaluation.
Breast Cancer Detection
| Study |
False Positive Rate |
| Over 10 years |
| Mammogram |
23.8% |
| Breast exam |
13.4% |
| Either |
31.7% |
| After 10 exams* |
| Mammogram |
49.1% |
| Breast exam |
22.3% |
| * - Estimated by the authors |
Not all of the suspicious studies lead to breast biopsy, however.
The authors did estimate that in women who will not
develop breast cancer, 18.6% will undergo biopsy by the time
they have had 10 mammograms and 6.2% will undergo breast biopsy
by the time they have had 10 breast exams over the age of 40.
Women need to be aware that there is this high of a rate of false
alarms. Unfortunately using present technology this is a price we
must pay to pick up breast cancers early. Physicians and
scientists must continue working to lower these instances of
false alarms.
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