An organized population-based breast cancer screening program in Norway and an approach to screening that relies on physician- and self-referrals in Vermont are equally sensitive for detecting cancer, researchers report in the July 29 online issue of the Journal of the National Cancer Institute. But the recall rate for abnormal mammograms was lower in Norway.
Breast cancer screening in the United States is usually initiated in response to a physician's recommendation (known as "opportunistic screening"), and women are advised to have annual screening mammograms. By contrast, breast cancer screening programs in Norway and in some other European countries regularly send letters to all women in a specific age range inviting them to have a screening mammogram. The Norway program aims for women to be screened every two years. The differences between the two approaches make it relatively difficult to compare their effectiveness, and few studies have aimed to do so previously.
In the current study, Berta Geller, Ed.D., of the University of Vermont in Burlington, Solveig Hofvind, Ph.D., of the Cancer Registry of Norway, and colleagues compared the screening approaches by looking at the percentage of women who were recalled for a re-evaluation, the screening detection rate of breast cancer, and the rate of interval cancers in 45,050 women in Vermont and 194,430 women in Norway from 1997 to 2003. Women included in the study were aged 50 to 69 years at the time of screening.