Performance measures of magnetic resonance imaging plus mammography in the High Risk Ontario Breast Screening Program
Menées au Canada auprès de 8 782 femmes présentant un risque élevé de cancer du sein et participant à un programme de dépistage (âge: 30 à 69 ans), ces deux études évaluent l'efficacité, du point de vue des taux de détection, de la sensibilité et de la spécificité, d'une IRM et d'une mammographie, combinées ou non, en fonction de catégories d'âge et de critères de risque
Background : The Ontario Breast Screening Program (OBSP) expanded in July 2011 to screen high risk women aged 30-69 with annual magnetic resonance imaging (MRI) and digital mammography. This study examined the benefits of screening with mammography and MRI by age and risk criteria.
Methods : This prospective cohort study included 8,782 women aged 30-69 years referred to the High Risk OBSP from July 2011 to June 2015, with final results to December 2016. Cancer detection rates (CDR), sensitivity, and specificity of MRI and mammography combined were compared to each modality individually within risk groups stratified by age using Generalized Estimating Equation models. Prognostic features of screen-detected breast cancers were compared by modality using Fisher’s exact test. All P values are two-sided.
Results : Among 20,053 screening episodes, there were 280 screen-detected breast cancers (CDR:14.0/1,000;95%CI:12.4-15.7). The sensitivity of mammography was statistically significantly lower than that of MRI plus mammography (40.8% [95%CI:29.3-53.5%] vs. 96.0% [95%CI:92.2-98.0%]; p < 0.001). In mutation carriers aged 30-39, sensitivity of the combination was comparable to MRI alone (100.0% vs. 96.8% [95%CI:79.2-100.0%]; p = 0.99), but with statistically significantly decreased specificity (78.0% [95%CI:74.7-80.9%] vs. 86.2% [95%CI:83.5-88.5%]; p < 0.001). In women aged 50-69, combining MRI and mammography statistically significantly increased sensitivity compared to MRI alone (96.3% [95%CI:90.6-98.6%] vs. 90.9% [95%CI:83.6-95.1%]; p = 0.02), with a small but statistically significant decrease in specificity (84.2% [95%CI:83.1-85.2%] vs. 90.0% [95%CI:89.2-90.9]; p < 0.001).
Conclusions : Screening high risk women 30-39 with annual MRI only may be sufficient for cancer detection and should be evaluated further, particularly for mutation carriers. Among women 50-69, detection is most effective when mammography is included with annual MRI.
Journal of the National Cancer Institute , résumé, 2018