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Objective:
Women with neurofibromatosis type 1 (NF1) have up to a 5-fold increased risk for breast cancer before age 50 and a 3.5-fold increased risk of breast cancer overall. Recent guidelines recommend annual screening mammography from age 30 with consideration of supplemental magnetic resonance imaging (MRI) between ages 30 and 50 years. However, scant information on breast imaging utilization and imaging-based outcomes exists for this population. The purpose of our study was to assess breast cancer screening utilization and breast imaging outcomes in an NF1 cohort.

Materials and Methods:
This IRB-approved, HIPAA-compliant study retrospectively assessed consecutive patients (January 2012 - December 2021) with an NF1 diagnosis and record of clinical visits and/or breast imaging. Patient demographic and risk factors were collected, and screening mammogram and breast MRI outcomes were recorded. Descriptive statistics were obtained for all variables, and standard breast screening measures were calculated.

Results:
A total of 135 patients (median age 40 years, range 18 - 82 at time of first clinical visit or imaging) met inclusion criteria of whom 111 women (median age 43 years, range 30 - 82) were eligible for screening; 86% (95/111) of all patients and 80% (24/30) of patients under age 40 had at least one mammogram. In contrast, 28% (31/111) of all patients and 33% (25/76) of patients ages 30 - 50 had at least one screening MRI. Of the 368 screening mammograms performed, 38/368 (10%) resulted in recall and 22/368 (6%) resulted in biopsy. Of the 48 screening MRIs performed, 19/48 (40%) short-term follow up examinations were recommended, and 12/48 (25%) biopsies were recommended and performed. All 6 cancers in our cohort were detected initially on screening mammogram. There were no interval cancers although there was one mammographically and sonographically occult cancer presenting as a palpable lump at the time of annual mammogram and diagnosed on palpation-guided biopsy. This cancer was visualized on subsequent MRI.

Conclusion:
Our patient population, including young women, was adherent to mammography screening guidelines. National mammography benchmarks were met with a recall rate of 10%, a PPV3 of 27%, and CDR of 16.3/1000, above accepted average-risk CDR benchmarks. However, the low utilization of MRI in our cohort limits evaluation of outcomes via this modality and suggests there may be an education or interest gap among referrers and patients regarding supplemental screening recommendations. MRI also resulted in a higher percentage of actionable findings compared to screening mammography, which is of concern in a cohort for whom multiple other extramammary imaging and screening tests may be recommended. Our results confirm the efficacy and utility of performing screening mammography in the NF1 population. The impact of supplemental screening with MRI requires further evaluation with a larger cohort, with the goal of assessing the optimal tools for identifying cancer early in the disease process while minimizing unnecessary imaging and procedures for these patients.