Mammography Study in BMJ Flawed: Discredited Data Used

Discredited and obsolete data used in Raftery and Chorozoglou, published Dec. 8 in the British Medical Journal, underestimated lives saved by mammography screening by half. The authors' comparison of inconvenience and anxiety of false positives to breast cancer deaths is also questionable.

“The estimated 15 percent reduction in breast cancer deaths used in this study is the same used in 2009 by the U.S. Preventative Services Task Force. That estimate has been discredited by a series of large randomized control trials and other data that prove the benefit is at least twice that,” said Barbara Monsees, MD, chair of the American College of Radiology Breast Imaging Commission. “While anxiety over test results is real, most women simply need another mammogram or ultrasound exam to answer questions about their mammogram. A small number will undergo a benign breast biopsy based on an abnormal screening and subsequent evaluation. However, most women would balk at comparing the anxiety of this with that of dying from breast cancer.”

Recently, Tabar et al, a landmark study, published in Radiology, that involved 130,000 women followed over 29 years, re-confirmed that regular mammography screening reduced the breast cancer death rate by 30 percent. This followed the largest breast cancer screening trial ever performed, Hellquist et al, published in Cancer, involving a million women over 16 years, which proved mammography screening reduced breast cancer deaths in women 40-49 by 29 percent.

Otto et al, published in the Dec. 6 Cancer Epidemiology, Biomarkers & Prevention, shows that mammography screening cuts the risk of dying from breast cancer nearly in half. According to National Cancer Institute data, since mammography screening became widespread in the early 1990’s, the U.S. breast cancer death rate, unchanged for the previous 50 years, has dropped well over 30 percent.

Yet, Rafftery and Chorozoglou estimate that mammography screening results in only a 15 percent reduction in breast cancer deaths - the same figure used in the discredited USPSTF recommendations. The U.S. government disavowed those recommendations and barred insurance companies from using them in coverage decisions. A recent analysis (Hendrick and Helvie), published in the American Journal of Roentgenology, showed that if USPSTF breast cancer screening guidelines were followed, approximately 6,500 additional women each year in the U.S. would die from breast cancer.

“No one can tell which cancers will never advance and which will become lethal. Therefore, until science can help to differentiate them, surgeons and medical oncologists will treat these patients, even though a small number of them may not benefit from treatment. The bottom line is that we know that discontinuing regular mammograms will result in thousands more breast cancer deaths each year. That human cost would be too high,” said Dr. Monsees.

Every major American medical organization with expertise in breast cancer care, including the American Congress of Obstetricians and Gynecologists (ACOG), American Cancer Society, American College of Radiology, and Society of Breast Imaging continue to recommend that women begin receiving annual mammograms at age 40.