Overdiagnosis Common with Public Breast Cancer Screening Programs

Last Updated: 2009-07-09 19:01:26 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Roughly one in three breast cancers detected in publically organized mammography screening programs is overdiagnosed, meaning that the malignancy will not cause symptoms or death in the patient"s lifetime, according to a report in the July 10th Online First issue of the British Medical Journal.

In the new study, Dr. Karsten Juhl Jorgensen and Dr. Peter C. Gotzsche, from The Nordic Cochrane Center, Copenhagen, analyzed how breast cancer rates changed after publicly organized screening programs were introduced in the UK, Canada, Australia, Sweden, and Norway.

Data from at least 7 years before and after the programs were introduced were analyzed and was obtained from both screened and non-screened age groups.

An increase in breast cancer rates was noted in each country that was closely associated with the introduction of screening, the report indicates. Moreover, very little of this increase was compensated for by a fall in breast cancer rates among previously screened women, the authors note.

The overall rate of overdiagnosis was 52% and ranged from 46% in Sweden to 59% in Canada. When only invasive breast cancers were considered, the rate of overdiagnosis was 35%.

In a related editorial, Dr. H. Gilbert Welch, from the Dartmouth Institute for Health Policy and Clinical Research, White River Junction, Vermont, comments that "the amount of overdiagnosis is a function of the mammographer"s threshold to recommend biopsy."

He adds that "the time has come for a randomized controlled trial to test higher thresholds, such as only recommending biopsy for breast masses larger than a certain size."

Source:

BMJ 2009.


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