WEDNESDAY, March 27, 2002 (HealthDayNews) -- Positioning for a mammogram is so crucial that your chance of a missed cancer diagnosis could double if your breast is not properly placed on the machine, a first-of-its kind study says.
Although many factors can affect the quality of a breast X-ray, including breast density and the contrast and sharpness of the procedure, positioning seems to be the one factor that makes the most difference in overall mammogram quality, the study in the April issue of the American Journal of Roentgenology found.
"We were looking for potentials that have an effect on cancer detection," says the study's lead author, Dr. Stephen Taplin, a senior investigator at the Group Health Cooperative's Center Health Studies in Seattle. "The one we found that was associated with missed cancer was positioning."
Mammograms, used to diagnose breast cancer, require that the breast be dramatically compressed, something many women find uncomfortable. But the positioning allows doctors to see the whole breast, including the nipple and the muscle behind the breast on the chest wall.
For the study, the researchers looked at mammograms from 656 women who developed breast cancer within two years of receiving a screening mammogram. At least one third of the mammograms had a problem with breast positioning, according to the study.
When the breast was positioned properly, only 15.6 percent of the cancers were not diagnosed at the time of the screening.
But 33.7 percent of cancers were missed in women whose breasts were not positioned properly.
"This is a good study that documents what mammographers and radiologists already know -- if you don't have a high quality [image], you'll miss cancers," says Dr. Ivy Engel, director of breast imaging at Nassau University Medical Center in East Meadow, N.Y.
Engel says it's sometimes hard to get the whole breast because it is uncomfortable for some women and they may move back slightly during the test.
"The main thing women need to do is interact with the technologist," says Taplin. "When they say lean in, it's important to do it even though it may be uncomfortable for a short period of time."
What to Do: To learn more about mammograms, read this information from Harvard University's Family Health Guide, or check out this mammography primer from the National Cancer Institute.
