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Annual Mammograms May Have More False-Positives


3 Star

Annual Mammograms May Have More False-Positives

Our Review Summary

This article reports on the results of a study of nearly 170,000 women who had screening mammograms beginning between age 40-59.  The study found that over ten years of screening mammograms, over half of the women will experience a false-positive recall for additional mammography.  In addition, 7%-9% of the women will have a biopsy for a suspicious lump which is not cancerous.

Both of those percentages decrease if the woman is screened every other year rather than every year.  Even with biennial mammography, 41% of women will experience a recall over 10 years of mammography.  The study’s Principal Investigator emphasized that “in most cases, a recall doesn’t mean you have cancer.”  She hoped this knowledge would reduce the anxiety of women who are recalled.

The story never explained the size of the decrease in the number of false positives between annual (61.3%) and biennial screening (41.6%).

Our first two reviewers were a researcher who specializes in health decisions and a breast cancer survivor trained in evidence by the Natiional Breast Cancer Coalition’s Project LEAD.


Why This Matters

This study is valuable because it helps to quantify and compare the harms of annual and biennial screening, specifically the number of false positives and the number of unnecessary biopsies.  Prior to this study, estimates of false positive screening mammography rates varied widely.

The critical question is whether you can do less frequent screening, subject women to fewer harms and get similar results in terms of detection of
“early stage” cancer. This study’s data seems to suggest that answer is yes.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

While the financial costs of screening mammography & false-positive recalls & biopsies were not included in the study, readers would benefit from being reminded that recall mammography & biopsies increase patient financial costs.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

This article leads with valuable information for all women over age 40 by stating “Getting screening mammograms every two years instead of annually reduces the chance of a false alarm, a new study shows.”  Unfortunately the writer doesn’t quantify or elaborate adequately on that reduction.  Instead, the writer later focuses on how women undergoing screening mammography shouldn’t be anxious if they experience a recall because over half of women who have screening mammograms for 10 years will be recalled.

Readers would have been better served if the writer had emphasized the significant reduction in both recall mammograms & false-positive biopsies in women who are screened every two years rather than annually.  Part of the continuing controversy over screening mammography focuses on annual versus biennial screening.  Because this study showed a significant reduction in the percentage of those recalled & needing biopsies among women who are screened every other year, with no statistically significant increase in late-stage diagnosis of breast cancer, the article should have emphasized those important findings.

Does the story adequately explain/quantify the harms of the intervention?


The piece states that the researchers noted that “…false positive recalls may cause inconvenience & anxiety and biopsies can cause pain and scarring.”

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

This article fails to include several important facts about the study.  1) This is a prospective cohort study of women screened between 1994-2006.  2) Most of the mammograms were film rather than digital.  3) Few women underwent screening for the entire 10 year period.  4) Screening mammography recall rates are influenced by the skill of the radiologists who read the mammograms.

Does the story commit disease-mongering?


There was no disease mongering.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

No independent experts were quoted.

Does the story compare the new approach with existing alternatives?


The story did an adequate job comparing – at a very high level – annual screening versus biennial screening.

Does the story establish the availability of the treatment/test/product/procedure?

Not Applicable

Screening mammography is widely available throughout the United States.

Does the story establish the true novelty of the approach?

Not Applicable

The study did not examine a new procedure.

Does the story appear to rely solely or largely on a news release?


There’s no evidence that the story relied solely on a news release.

Total Score: 4 of 8 Satisfactory


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