Introduction/Background*Breast cancer (BC) tumor size (TS) at diagnosis is one of the most important prognostic factors and represent a pivotal key driver of treatment planning for patients with BC. The aim of this study was to evaluate the place of complementary breast magnetic resonance imaging (MRI) for preoperative TS evaluation in patients with early stage BC according to menopausal status.

Methodology We performed a retrospective review of a prospectively collected database of patients treated by primary surgery at a single institution for unifocal invasive BC who had complete documentation of the tumor size from mammography (MMG), ultrasonography (US), and MRI. Pearson’s correlation (rs) coefficients are reported with their linear relationships.

Result(s)*A total of 752 women with 757 BC tumors were analyzed. Median age was 61.1 years (range from 26 to 89). There were 591 (78.6%) women with a postmenopausal status. Invasive ductal carcinoma (IDC) was present in 84% of tumors. The mean (SD) histopathological TS was 15.2 (8.3) mm. The tumor size varied by imaging method: 13.7 (7.3) mm for MMG, 13.1 (7.4) mm for US, and 16.4 (9.1) mm for MRI. Correlations between TS assessed by the breast imaging technique (BIT) and by histopathology were 0.80 for MRI, 0.75 for US, and 0.69 for MMG. There was an rs of 0.72 for MRI and US in premenopausal women while the rs for MMG was 0.64, in the same group of patients. The correlations between the final pathology and BIT in postmenopausal patients were 0.83 for MRI, 0.76 for US, and 0.70 for MMG.

Conclusion*Correlations between tumor size determined by BIT and final pathological size remained higher with MRI than US or MMG examination. Menopausal status may influence the accuracy of TS estimation, with a better correlation in postmenopausal women for all BIT.