HR-MRI of the Breast at Intervals of Maximum 24 Months: Influence on Tumor Stage at the Time of Diagnosis

Abstract

Purpose: To define the value of repetitive performed exclusive MRI of the breast at intervals of maximum 24 months in asymptomatic women and patients regarding the tumor size and stage at the time of diagnosis. Material and methods: Women with normal MRI of the breast upon initial examination and subsequent breast MRI within intervals of maximum 2 years were included. Benign and malignant lesions as well as the tumor stages were reported and analysed. Results: 8.975 MRI were performed in 2333 women. 6642 exams were subsequent MRI (2.85 follow-up MRI/woman). Within the examination intervals, 290 (4.37% per follow up exam) lesions categorized as MR-BIRADS 4/5 were found in 272 patients. All of these findings were clarified by percutaneous biopsy. Histology revealed benign findings (B1/B2) in 151/290 (52.1%), B3-lesions in 24 (8.3%), and malignant tumors (B5a/B5b) in 115 cases (39.6%). Open biopsy revealed an intraductal carcinoma in 36/115 cases (G1: 11, G2: 16, G3: 9), and an invasive breast cancer in 79/115 cases. Tumor stages of the invasive carcinoma were pT1a (17/79; 21.5%), pT1b (39/79, 49.4%), and pT1c (22/79; 27.8%). Only one invasive cancer was classified as stage pT2. The average size of all invasive tumors was 9.0 mm. Rate of nodal negative invasive cancer was 95.9%. Rate of interval carcinomas was less than 2%. Conclusion: The performance of repetitive MRI of the breast at intervals of maximum 24 months allows the reliable detection of breast cancer at an early stage (pTis, pT1a, pT1b, pN0) with an excellent prognosis.