Comparative Accuracy of Preoperative Tumor Size Assessment on Breast Ultrasonography and Magnetic Resonance Imaging in Young Breast Cancer Patients

Received March 5, 2020 Revised March 31, 2020 Accepted April 6, 2020 Purpose: Breast cancer in young women deserves special consideration, such as dense breast, more aggressive progression, and oncoplastic surgery. Magnetic resonance imaging (MRI) is a more recent modality than ultrasonography (US), but the role of MRI in patients with a dense breast is still controversial. This comparative study analyzed the relationship between the preoperative radiological and the postoperative pathological tumor size for young breast cancer patients. Methods: All breast cancers diagnosed in patients 45 years or younger from January 2016 to December 2018 were reviewed. Tumor size measurements obtained on breast US and MRI were compared for accuracy with those obtained in the final pathology results. Patients with only microcalcification on imaging modalities and those who had undergone neoadjuvant chemotherapy were excluded. Results: A total of 103 breast cancer patients were included in this study. Of the 103 breast cancers with both imaging modalities performed, 86 (83.5%) were infiltrating ductal carcinomas and 17 (16.5%) were ductal carcinoma in situ. The mean tumor size measured on MRI was significantly greater than that measured on pathology (18.5 ± 11.0 mm vs. 16.6 ± 8.5 mm), whereas the sizes measured on US was not significantly different from that measured on pathology (16.5 ± 9.5 mm vs. 16.6 ± 8.5 mm). The tumor size measured on MRI was greater than that measured on US. Conclusion: Measurements taken by US were more accurate in measuring the tumor size in patients 45 years of age or younger than MRI.