(HealthDay News) — Breast cancer risk estimates for individual women vary substantially depending on which risk assessment model is used, according to a study published online Feb. 7 in the Journal of General Internal Medicine.
Jeremy S. Paige, M.D., Ph.D., from the University of California in Los Angeles, and colleagues assessed the accuracy and disagreement between three commonly used risk models (Breast Cancer Risk Assessment Tool [BCRAT], Breast Cancer Surveillance Consortium [BCSC] model, and International Breast Intervention Study [IBIS] model) in categorizing individual women as average versus high risk for developing invasive breast cancer. The analysis included 31,115 women (40 to 74 years) presenting for screening mammography at a multisite health system between 2011 and 2015 with five-year follow-up.
The researchers found that when using the ≥1.67 percent threshold, more than 21 percent of women were classified as high risk for developing breast cancer in the next five years by one model but were classified as average risk by another model. When using the ≥3.0 percent threshold, more than 5 percent of women had disagreements in risk severity between models. For the threshold of ≥1.67 percent, almost half of the women (46.6 percent) were classified as high risk by at least one of the three models versus 11.1 percent when using the ≥3.0 percent threshold. At the population level, all three models had similar accuracy.
“Women are likely receiving vastly different recommendations depending on which breast cancer risk model is used and which cutoff is used to define ‘high risk,'” the authors write.
One author receives royalty payments from licenses for commercial use of the IBIS algorithm, through Cancer Research U.K.