August 13, 1999

New computer model supports the importance of annual mammograms

The fact that a woman has had a mammogram "within the past few years" is not sufficient to protect her from breast cancer, says a group of MGH researchers. In a study published in the August issue of Radiology, the investigators show that the interval between mammograms may be the most critical factor for reducing the breast cancer death rate. The conclusions are based on a new computer model developed by James Michaelson, PhD, of the MGH Cancer Center, in collaboration with Elkan Halpern, PhD, and Daniel Kopans, MD, MGH director of Breast Imaging. The model suggests that, if women had mammograms more frequently than most of them currently do, more tumors would be discovered at a stage when they are curable by surgery and radiation.

"The findings described here suggest that screening, if used frequently enough, has the potential to reduce breast cancer deaths dramatically beyond what has already been shown in trials of screening mammography," says Michaelson. He and his colleagues note that, while MGH physicians consistently have urged prompt annual screening, those women who have come to the hospital for their mammograms actually wait an average of a year and a half between examinations, with many going two, three or more years between screenings.

Kopans adds, "I suspect that many women find it easy to delay having their mammograms – healthy people are rarely anxious to go looking for cancer. This model suggests, however, that the time between screenings is actually extremely important. If we are to save the most lives possible, women need to comply with the general recommendation of a prompt yearly mammogram."