Breast Density as a Predictor of Mammographic Detection: Comparison of Interval- and Screen-Detected Cancers Margaret T. Mandelson, Nina Oestreicher, Peggy L. Porter, Donna White, Charles A. Finder, Stephen H. Taplin, Emily White Affiliations of authors: M. T. Mandelson, Center for Health Studies, Group Health Cooperative, Seattle, WA, and Department of Epidemiology, University of Washington, Seattle; N. Oestreicher, E. White, Program in Cancer Prevention Research, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, and Department of Epidemiology, University of Washington; P. L. Porter, Program in Cancer Biology, Divisions of Human Biology and Public Health Sciences, Fred Hutchinson Cancer Research Center, and Department of Pathology, University of Washington; D. White, Department of Radiology, Group Health Cooperative; C. A. Finder, Division of Mammography Quality and Radiation Programs, Food and Drug Administration, Rockville, MD; S. H. Taplin, Center for Health Studies, Group Health Cooperative, and Department of Family Medicine, University of Washington. Correspondence to: Margaret T. Mandelson, Ph.D., Center for Health Studies, Group Health Cooperative, 1730 Minor Ave., Suite 1600, Seattle, WA 98101 (e-mail: mandelson.m@ghc.org). Background: Screening mammography is the best method to reduce mortality from breast cancer, yet some breast cancers cannot be detected by mammography. Cancers diagnosed after a negative mammogram are known as interval cancers. This study investigated whether mammographic breast density is related to the risk of interval cancer. Methods: Subjects were selected from women participating in mammographic screening from 1988 through 1993 in a large health maintenance organization based in Seattle, WA. Women were eligible for the study if they had been diagnosed with a first primary invasive breast cancer within 24 months of a screening mammogram and before a subsequent one. Interval cancer case subjects (n = 149) were women whose breast cancer occurred after a negative or benign mammographic assessment. Screen-detected control subjects (n = 388) were diagnosed after a positive screening mammogram. One radiologist, who was blinded to cancer status, assessed breast density by use of the American College of Radiology Breast Imaging Reporting and Data System. Results: Mammographic sensitivity (i.e., the ability of mammography to detect a cancer) was 80% among women with predominantly fatty breasts but just 30% in women with extremely dense breasts. The odds ratio (OR) for interval cancer among women with extremely dense breasts was 6.14 (95% confidence interval [CI] = 1.95–19.4), compared with women with extremely fatty breasts, after adjustment for age at index mammogram, menopausal status, use of hormone replacement therapy, and body mass index. When only those interval cancer cases confirmed by retrospective review of index mammograms were considered, the OR increased to 9.47 (95% CI = 2.78–32.3). Conclusion: Mammographic breast density appears to be a major risk factor for interval cancer. Ann's NOTE: The lesson for patients and advocates is to ASK if your breasts are showing up as dense. If they are dense, then ask for a sonogram as it may help determine what is going on. If you came in with a lump and you have dense breast, a mammogram MAY not be helpful. You may want to have a needle biopsy or a surgical biopsy to get more information on what is going on in your breast. Keep in mind that a surgical biopsy can create scar tissue which hinders future mammograms. A way to reduce scar tissue is to rub cocoa butter on the area every day for at least 3 months. Br Med J,12/01 Cancer Epidemiology, Biomarkers & Prevention, 12/98 Breast Cancer Res 1/02 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.