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. RSNA, 2017 Online supplemental material is available for this article.

Contrast‐enhanced MRI for breast cancer screening

“…Strigel et al only reported a higher incidence of node‐positive invasive cancers, albeit this was a much smaller study . Vreemann et al showed that performance of screening is highly dependent on the actual screening indication . For example, the sensitivity of the screening program was only 81% in BRCA1 carriers, whereas it exceeded 90% for all other indications, which is likely an effect of the fast growth of cancers in these women.…”

“…It is important to realize that this is no longer true, even when studies are still presenting MRI as a supplemental test . The incremental cancer detection with mammography ranges from 0–19.4% . However, the study by Sung et al reports on MRI and mammography examinations that were not simultaneously obtained and should therefore likely be disregarded in this sense .…”

“…34,36 The incremental cancer detection with mammography ranges from 0-19.4%. [22][23][24][25][26][27][28][29][30][31][32] However, the study by Sung et al reports on MRI and mammography examinations that were not simultaneously obtained and should therefore likely be disregarded in this sense. 31 Hence, the added sensitivity with mammography is around 5%, ranging from 0-8.6%.…”

“…95 Vreemann et al showed that performance of screening is highly dependent on the actual screening indication. 27 For example, the sensitivity of the screening program was only 81% in BRCA1 carriers, whereas it exceeded 90% for all other indications, which is likely an effect of the fast growth of cancers in these women. Recently, Guindalini et al showed that with a biannual breast MRI screening protocol, the frequency of interval cancers in this group was 0.…”

“…Recently, Guindalini et al showed that with a biannual breast MRI screening protocol, the frequency of interval cancers in this group was 0. 96 On the other hand, Vreemann et al 27 reported a positive predictive value for biopsy of only 14% in women with a positive family history as the only risk factor, whereas it was around 30% for most other indications, which is due to the lower prevalence of cancer in the familial risk group. This implies that it is of paramount importance to be aware of the screening indication and adjust recall and biopsy thresholds depending on the degree of individual risk.…”