99mTc-3PRGD2 Scintimammography in Palpable and Nonpalpable Breast Lesions

The aim of this study was to explore the diagnostic performance of Tc-99m-3(poly-(ethylene glycol), PEG) 4-RGD(2) (Tc-99m-3PRGD(2)) scintimammography (SMM) in patients with either palpable or nonpalpable breast lesions and compare SMM to mammography to assess the possible incremental value of SMM in breast cancer detection. We also investigated the alpha(v)beta(3) expression in malignant and benign breast lesions. Ninety-four patients with 110 lesions were included in this study. Mammograms were evaluated according to the Breast Imaging Reporting and Data System (BI-RADS) by a specialized imaging radiologist. Prone SMM was performed 1 hour after injection of Tc-99m-3PRGD(2). Scintigraphic images were interpreted independently by two experienced nuclear medicine physicians using a three-point system, and the kappa value was calculated to determine the interreader agreement. The McNemar test was used to compare SMM and mammography with respect to sensitivity, specificity, and accuracy. Diagnostic values for breast cancer detection were evaluated for each lesion. Immunohistochemistry was performed to evaluate integrin avb3 expression. Histopathology revealed 46 malignant lesions and 64 benign lesions. The overall sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of SMM were 83%, 73%, 77%, 69%, and 85%, respectively. The kappa value between the two reviewers was 0.63. The diagnostic values of SMM were higher than those of mammography in evaluating overall breast lesions. A sensitivity of 91% was achieved when SMM and mammography results were combined with 60% of all false-negative mammography findings classified as true-positive results by SMM. Integrin avb3 expression was positively identified using SMM imaging. SMM is a promising tool to avoid unnecessary biopsies when used in addition to mammography and can be used to image avb3 expression in breast cancer with good image quality.