Performance Measures of Magnetic Resonance Imaging Plus Mammography in the High Risk Ontario Breast Screening Program

Abstract

Background The Ontario Breast Screening Program expanded in July 2011 to screen high-risk women age 30–69 years 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 8782 women age 30–69 years referred to the High Risk Ontario Breast Screening Program from July 2011 to June 2015, with final results to December 2016. Cancer detection rates, sensitivity, and specificity of MRI and mammography combined were compared with 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 exact test. All P values are two-sided. Results Among 20 053 screening episodes, there were 280 screen-detected breast cancers (cancer detection rate = 14.0 per 1000, 95% confidence interval [CI] = 12.4 to 15.7). The sensitivity of mammography was statistically significantly lower than that of MRI plus mammography (40.8%, 95% CI = 29.3% to 53.5% vs 96.0%, 95% CI = 92.2% to 98.0%, P < .001). In mutation carriers age 30–39 years, sensitivity of the combination was comparable with MRI alone (100.0% vs 96.8%, 95% CI = 79.2% to 100.0%, P = .99) but with statistically significantly decreased specificity (78.0%, 95% CI = 74.7% to 80.9% vs 86.2%, 95% CI = 83.5% to 88.5%, P < .001). In women age 50–69 years, combining MRI and mammography statistically significantly increased sensitivity compared with MRI alone (96.3%, 95% CI = 90.6% to 98.6% vs 90.9%, 95% CI = 83.6% to 95.1%, P = .02), with a small but statistically significant decrease in specificity (84.2%, 95% CI = 83.1% to 85.2% vs 90.0%, 95% CI = 89.2% to 90.9%, P < .001). Conclusions Screening high risk women age 30–39 years with annual MRI only may be sufficient for cancer detection and should be evaluated further, particularly for mutation carriers. Among women age 50–69 years, detection is most effective when mammography is included with annual MRI.

Trends in screening breast magnetic resonance imaging use among US women, 2006 to 2016

“…Screening breast MRI rates were found to be lowest in younger women compared with women aged 50 to 64 years with BRCA mutations, even though younger women may benefit the most from breast MRI. 3,17 Breast cancer incidence in BRCApositive women rapidly increases during their 30s and 40s before rates stabilize during a woman's 50s. 18 Furthermore, women of reproductive age face the dual conflict of family planning while mitigating cancer risk with prophylactic mastectomy and oophorectomy.…”

“…However, nearly 4 of every 5 observed screening breast MRI examinations were performed in the 2 nonrecommended risk subgroups in the current study, and rate increases have slowed since the initial rise in 2006 through 2008. Screening breast MRI rates were found to be lowest in younger women compared with women aged 50 to 64 years with BRCA mutations, even though younger women may benefit the most from breast MRI 3,17 . Breast cancer incidence in BRCA‐positive women rapidly increases during their 30s and 40s before rates stabilize during a woman's 50s 18 .…”

Breast cancer risk, worry, and anxiety: Effect on patient perceptions of false-positive screening results

“…However, in women at high risk for breast cancer such as BRCA mutation carriers, mammography detects less than half of all breast cancers, possibly due to young patient age and increased breast density, or tumor pathologic factors [ 3 , 4 ]. As such, women at high risk for breast cancer are offered more intensive screening at younger ages and with supplemental modalities such as magnetic resonance imaging (MRI) [ 5 , 6 ] which has been shown to improve cancer detection [ 7 , 8 ] and reduce the incidence of advanced stage breast cancers [ 9 ] when used for high-risk screening.…”

The supplemental value of mammographic screening over breast MRI alone in BRCA2 mutation carriers

“…The prospective cohort study of the High Risk Ontario Breast Screening Program [23] included, from July 2011 to December 2016, 8782 high-risk women, of which 1885 were BRCA1/2 mutation carriers. In mutation carriers, younger than 40 years of age the sensitivity of MRI alone was comparable to the combination of MRI and mammography (96.8% vs 100%, p 0.99).…”