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

BACKGROUND: As physicians increasingly use magnetic resonance imaing (MRI) for the evaluation of newly diagnosed breast cancers, a review of the correlation between MRI and pathology tumor size is imperative. METHODS: A retrospective review of 91 breast tumors comparing preoperative MRI tumor size to final pathology tumor size was performed. RESULTS: MRI 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). CONCLUSIONS: MRI 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). (C) 2008 Elsevier Inc. All rights reserved.