Berta Geller, research professor of family medicine is a co-author on a Dec. 16 Journal of the National Cancer Institute article titled "Biennial Versus Annual Mammography and the Risk of Late-Stage Breast Cancer." The study sought to determine whether there was an increased risk of late-stage breast cancer in women screened every two years versus annually. The researchers found no increase in risk in women over 50, but greater risk in women in their 40s. Geller is principal investigator of the Vermont Breast Cancer Surveillance System, which is a member of a group that contributed to the report, the National Cancer Institute's Breast Cancer Surveillance Consortium ˜ a group of seven breast cancer registries across the country in cooperative agreement with the National Cancer Institute.