Study Concludes That Mammography Can Lead to Unnecessary Lumpectomies, Mastectomies and Radiation Therapy

For every 2,000 women who use mammography to screen for breast cancer in a ten-year period, ten healthy women will be diagnosed incorrectly with breast cancer and will be treated unnecessarily. Such treatments may include lumpectomies, mastectomies and radiation therapy. This is the conclusion from a recently published Cochrane Review¹. Written by healthcare specialists, Cochrane Reviews explore the effectiveness and appropriateness of treatments in specific circumstances.

In fact, these conclusions are not new. The value of routine mammography for breast cancer screening was challenged as early as 1995. In an article that appeared in the medical journal Lancet, the authors stated, "Since the benefit achieved (by mammography) is marginal, the harm caused is substantial, and the costs incurred are enormous, we suggest that public funding for breast cancer screening in any age group is not justifiable."²

Mammography is Standard of Care

Despite these criticisms, mammography has become the de facto Breast cancer screening tool used throughout the United States. breast cancer is one of the most significant health concerns in the U.S. and the U.S. Preventive Services Task Force recommends mammography for women older than 40 years who are in good health. Although mammography is a relatively inexpensive procedure (Medicare reimbursement is currently $85.65 for a plain film screening mammography), it costs approximately $1.9 billion per year when you count the millions of mammograms performed annually.³

Some Mammography Studies May Be Biased

There have been other mammography studies that have suggested that this diagnostic tool is more valuable than what was presented by the Cochrane Review. However, according to a recent medical journal article (written by one of the same authors as the Cochrane Review) "Scientific articles tend to emphasize the major benefits of mammography screening over its major harms. This imbalance is related to the authors' affiliation."⁴ They found that medical articles that downplayed "over diagnosis" (diagnosing breast cancer when there isn't any) and emphasized a reduction in breast cancer mortality were more often written by people who worked with mammography (and presumably had a financial interest) as opposed to writers who were unrelated to screening.

False Positives

Whether one is for or against screening mammograms, the issue of false positives must be taken seriously. False positives like "over diagnosis" means that the person reading the mammography concludes there is cancer or something suspicious when the breast tissue is actually normal. In the United States, approximately 11% of screening mammograms lead to false-positive results, which can cause women to incur substantial personal and financial costs related to follow-up testing.⁵ At best, a false positive leads to a repeat mammography or some other non-interventional testing. At worse, a false positive can begin a cascade of events that eventually leads to biopsy, mastectomy or some other unnecessary and debilitating therapy or test.

One fascinating study published in the Journal of the National Cancer Institute examined false positive mammograms by analyzing the results of twenty-four radiologists. The study found that the false positive rates of individual radiologists varied from 2.6% to 15.9%. Incredibly, some radiologists had a false positive rate up to six times more than other radiologists (before adjustment for patient characteristics and other variables). The researchers found that the most important characteristic that impacted false positives appeared to be the radiologist's age and time since graduation from medical school. Younger radiologists and those more recently in training had significantly higher rates of false-positive mammograms.⁶

Conclusions

Mammography screening likely reduces breast cancer mortality. But, screening also leads to wrong diagnosis and "overtreatment." Women should stay well informed of the risks and benefits of this diagnostic test. In the case of an "abnormal" mammography it may be prudent to ask for a second opinion from an experienced radiologist before therapies, biopsies or surgeries are considered.

End Notes

1. Gøtzsche PC, Nielsen M. Screening for breast cancer with mammography. Cochrane Database Syst Rev. 2006 Oct 18;(4):CD001877.
2. Wright CJ and Mueller CB. Screening mammography and public health policy: the need for perspective. Lancet. 1995 Jul 1;346(8966):29-32.
3. This estimate is based on the following facts and assumptions: 1) CDC researchers found that 74.6 percent of women over 40 got mammograms in 2005; The population of women over the age of 40 in the U.S, is approximately 62 million; Average Medicare reimbursement per screening mammogram is $85.65. Assumption - 74.6% of women over 40 receive a screening mammogram on average once every two years. Total = $1,965,710,000.
4. Jørgensen KJ, Klahn A, Gøtzsche PC. Are benefits and harms in mammography screening given equal attention in scientific articles? A cross-sectional study. BMC Med. 2007 May 30;5:12.
5. Noel T. Brewer, PhD, et al., Systematic Review: The Long-Term Effects of False-Positive Mammograms Ann Intern Med. 2007;146:502-510.
6. Elmore JG, et al., Screening mammograms by community radiologists: variability in false-positive rates. J Natl Cancer Inst. 2002 Sep 18;94(18):1373-80.