Questionable docs: state guides for sale

Healthfacts, August, 1996

The push is on to get all women over the age of 50 on estrogen therapy to prevent heart disease and osteoporosis. But this hormone drug regimen may make it more difficult to diagnose breast cancer. In many women, estrogen increases breast density, which makes mammograms more difficult to interpret. Dense breast tissue does not provide enough contrast on an x-ray.

The finding was confirmed in a new study of nearly 9,000 postmenopausal women who were enrolled in the breast cancer screening program of a health maintenance organization in Washington State (Journal of the National Cancer Institute, 15 May 1996). The group contained a mix of women who were current, past, or never users of estrogen.

Current use of estrogen was associated with an increased likelihood of false mammogram interpretations. The errors were both false-positive (erroneous indication of cancer) as well as false-negative (erroneous indication that the breast is cancer-free). The presence of dense breast tissue accounts for mammography's lower accuracy in detecting breast cancer in younger women.

Last month we reported Merck's misleading ad campaign for its new osteoporosis drug, Fosamax. Though the published evidence shows a modest benefit to high-risk elderly women with osteoporosis, Merck's ads convey the yet-to-be proven idea that Fosamax can be prescribed to mid-life healthy women in order to prevent osteoporosis.

In a move that will undoubtedly create more Fosamax customers, Merck recently announced that it has reached a financial agreement with two manufacturers of bone density measurement equipment. The agreement is intended to increase the availability of bone densitometers in doctors' offices. The more women given bone measurement tests, the more bone loss will be detected.

Keep in mind that bone loss is largely a function of aging and the definition of osteoporosis is arbitrary.