Estimating the impact of mammography screening disruptions during the COVID-19 pandemic

PROJECT SUMMARY/ABSTRACTBreast density is a risk factor for developing breast cancer and decreases the accuracy of screeningmammography. An estimated 27 million women aged 40-74 in the U.S. have dense breasts and theyexperience elevated rates of advanced stage breast cancer diagnoses associated with poor outcomes. Thirty-seven states now require mammography facilities to notify women with dense breasts of the limitations ofmammography and recommend discussion of screening options with their healthcare providers, and a nationallaw is pending. In the absence of screening guidelines for women with dense breasts, there has been adramatic increase in use of supplemental ultrasound screening, which is widely available and has low directmedical costs. Early studies of supplemental ultrasound performance suggest increased cancer detection buthigh rates of false positive exams leading to unnecessary biopsies. The United States Preventive ServicesTask Force has called for studies that evaluate the impact of supplemental ultrasound screening on meaningfulclinical outcomes, such as advanced cancer rates, to inform screening guidelines for women with densebreasts. We recently demonstrated that mammography screening failure rates (i.e., advanced cancers andinterval cancers after a normal mammogram) among women with dense breasts vary widely according toclinical risk factors. Therefore, we propose to assess supplemental ultrasound screening performance within anew risk-based framework. We hypothesize that supplemental ultrasound screening targeted to the subset ofwomen with dense breasts at high risk of mammography screening failures will yield a favorable benefit-to-harm profile. We will use observational data from more than 100,000 screening ultrasound exams and 2 millionmammography screening exams collected via the Breast Cancer Surveillance Consortium to (Aim 1) examinethe test performance of supplemental screening ultrasound according to technique (handheld vs. automated)and type of primary screening (digital mammography vs. digital breast tomosynthesis); and (Aim 2) evaluatesupplemental screening ultrasound outcomes across levels of risk for mammography screening failures. Theseresults will be used as inputs in two simulation models from the Cancer Intervention and Surveillance ModelingNetwork to (Aim 3) evaluate the long-term benefits, harms, and costs of supplemental ultrasound strategiestargeted to women at high risk of mammography screening failures. Our study will be the largest evaluation ofsupplemental ultrasound and the first to evaluate rates of interval and advanced cancers according to risk ofmammography screening failures. Our results will provide urgently needed, actionable evidence for women,healthcare providers, and guideline-makers evaluating screening options for women with dense breasts. Thisevidence will support effective supplemental screening strategies that reduce the burden of breast canceramong women for whom mammography screening is not adequate, while minimizing potential harms.