A critical audit of a breast MRI screening programme for intermediate and high risk patients in clinical practice

Purpose: Breast MRI is used to screen for breast cancer in women at elevated risk. However, contrary to common practice in mammography screening, no structural quality assessment of MRI screening is performed. The purpose of this audit was to evaluate the visibility of MR screen-detected cancers on prior MR examinations. Methods and Materials: Patient files from all women who were diagnosed with breast cancer after a positive MRI screen between 2003 and 201 3 were reviewed. We selected all cases where a previous MR examination was performed between 6 and 24 months before detection. This yielded 42 cancers (3 lobular-, 38 ductal carcinomas, 1 secretory carcinoma) in 40 women (1 bilateral, mean age 50 years A,A+- 9.7 years). The diagnostic and prior MRI studies were evaluated side-by-side in consensus by two dedicated breast radiologists. The visibility of the cancers on the prior scans was rated as: Visible (BIRADS 4/5), Minimal sign (BIRADS 2/3), and Occult (BIRADS 1). Results: The mean interval between the prior and diagnostic MRI was 1 1 .9 months A,A+- 3.3 months. All 42 lesions were identified on the diagnostic scans. Eleven lesions (26%) were visible in the prior MRI and should have already been recalled. Thirteen lesions (31 %) showed a minimal sign in the prior MRI. Only 18 lesions (43%) were completely occult. Conclusion: In 26% of cases, evident lesions were missed in prior MRI screening exams. To prevent these errors structural double reading of MR screening examinations may be indicated.