Breast cancer tumor size: correlation between magnetic resonance imaging and pathology measurements

BackgroundAs physicians increasingly use magnetic resonance imaging (MRI) for the evaluation of newly diagnosed breast cancers, a review of the correlation between MRI and pathology tumor size is imperative.MethodsA retrospective review of 91 breast tumors comparing preoperative MRI tumor size to final pathology tumor size was performed.ResultsMRI and pathology tumor size were positively correlated (R = .650), but with an average overestimation by MRI of .63 cm (P <.0001). When stratified by MRI tumor size (≤2.0 cm and >2.0 cm), a significant difference was found only in tumors greater than 2.0 cm (average overestimation = 1.06 cm; P <.0001). This trend continued for the histological subtypes of ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), and invasive lobular carcinoma (ILC).ConclusionsMRI tumor size correlates with pathology size; however, a significant overestimation exists, particularly for tumors >2.0 cm. Clinicians should therefore use caution in relying on MRI tumor size in determining candidacy for breast conservation therapy (BCT).