Breast Cancer Screening: New Fuel for an Old War of Words and Data

Nov. 20, 2009— -- A controversy that has alternately simmered and boiled for more than 40 years reached a flash point this week when the U.S. Preventive Services Task Force published recommendations for breast cancer screening with mammography.The recommendation to delay routine screening in average-risk women until age 50 brought out ardent supporters on both sides of the issue, as reflected in coverage by MedPage Today and in consumer and professional media from coast to coast.

Although media coverage might have created the impression of a new controversy, the strong, conflicting opinions go back at least as far as 1969, when initial results of the first large-scale breast cancer screening program were announced. Data from the Health Insurance Plan (HIP) of Greater New York, published in the Journal of the American Medical Association in 1971, showed a 30 percent reduction in breast cancer deaths in women ages 40 to 64 who underwent clinical breast examination and screening mammography.

With longer follow-up, the HIP data suggested the benefits of screening in terms of reducing death in women was limited to women ages 50 and older. By 1977, the authors of that study had concluded that women ages 40 to 49 did not benefit from screening.

Shortly afterward, a Swedish study published in 1981 in the journal Radiology demonstrated a beneficial effect of breast cancer screening in women ages 40 to 74. In contrast to the HIP data, follow-up for as long as 20 years showed lower deaths in women ages 40 to 49, as well as older age groups, according to a 2003 Lancet study.

Several other studies reinforced the value of breast cancer screening, and mammography gained widespread acceptance among physicians and scientists alike. However, disagreements persisted about the purported benefits of screening in younger women and about the appropriate screening interval.