Background: Diagnostic accuracy of MRI in predicting breast tumor size: comparative analysis of breast tumor size byMRI vs histopathological assessment.
Purpose: Tumor size is one of the most important factors in making a clinical and pathological assessment of breast cancer. The purpose of this study is to evaluate if MRI imaging is helpful for the surgeon in the preoperative accurate assessment of tumor size.
Methods: We retrospectively reviewed the charts of 124 patients who were diagnosed or managed at the Saint Francis /Mt. Sinai Regional Cancer Center. We then compared the preoperative MRI tumor size with the histopathological tumor size obtained at surgical resection. Tumors were divided into four histological groups: invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), ductal carcinomain situ (DCIS), and mixed tumors (including mucinous, papillary, tubular, and apocrine breast carcinoma). MRI measurement of tumor size was compared against the reference size obtained from the microscopic measurement of the largest diameter of tumors. Concordance was defined as a difference ≤ 0.5 cm between MRI and pathology.
Results: A total of 124 patients with 147 breast tumors were included in our study. The mean age was 59.8 ± 12.72 years. Histologically, there were 81 IDC (55.10%), 35 DCIS (23.81%), 15 ILC (10.20%), and 16 mixed tumors (10.88%). Out of 147 tumors, 55.78% showed concordance of MRI and pathologic tumor size within 0.5 cm. MRI overestimated 31.97% and underestimated 12.24% of tumors.
Conclusion: Breast MRI provides an additional tool for preoperative assessment of tumor size. In our study, we noted 56% concordance between MRI with pathological tumor size within 0.5 cm. Several factors, including grading of tumor, cancer type, and size, strongly affect the accuracy of MRI in the preoperative assessment of tumor size. High-grade tumor and DCIS are the two strongest negative factors resulting in overestimation of tumor size on MRI.