Influence of risk category and screening round on the performance of an MR imaging and mammography screening program in carriers of the BRCA mutation and other women at increased risk

Abstract

Purpose: To evaluate the real-life performance of a breast cancer screening program for women with different categories of increased breast cancer risk with multiple follow-up rounds in an academic hospital with a large screening population. Materials and Methods: Screening examinations (magnetic resonance [MR] imaging and mammography) for women at increased breast cancer risk (January 1, 2003, to January 1, 2014) were evaluated. Risk category, age, recall for workup of screening-detected abnormalities, biopsy, and histopathologic diagnosis were recorded. Recall rate, biopsy rate, positive predictive value of recall, positive predictive value of biopsy, cancer detection rate, sensitivity, and specificity were calculated for first and follow-up rounds. Results: There were 8818 MR and 6245 mammographic examinations performed in 2463 women. Documented were 170 cancers; of these, there were 129 screening-detected cancers, 16 interval cancers, and 25 cancers discovered at prophylactic mastectomy. Overall sensitivity was 75.9% including the cancers discovered at prophylactic mastectomy (95% confidence interval: 69.5%, 82.4%) and 90.0% excluding those cancers (95% confidence interval: 83.3%, 93.7%). Sensitivity was lowest for carriers of the BRCA1 mutation (66.1% and 81.3% when including and not including cancers in prophylactic mastectomy specimens, respectively). Specificity was higher at follow-up (96.5%; 95% confidence interval: 96.0%, 96.9%) than in first rounds (85.1%; 95% confidence interval: 83.4%, 86.5%) and was high for both MR imaging (97.1%; 95% confidence interval: 96.7%, 97.5%) and mammography (98.7%; 95% confidence interval: 98.3%, 99.0%). Positive predictive value of recall and positive predictive value of biopsy were lowest in women who had only a family history of breast cancer. Conclusion: Screening performance was dependent on risk category. Sensitivity was lowest in carriers of the BRCA1 mutation. The specificity of high-risk breast screening improved at follow-up rounds.