The preoperative role of breast-specific gamma imaging for the breast cancer patients: In comparison with conventional imaging modality

Purpose: We wanted to assess the clinical efficacy of breastspecific gamma imaging (BSGI) as compared with that of conventional imaging modalities (mammography, ultrasonography and magnetic resonance imaging) as a preoperative examination for patients with breast cancer. Methods: From April to May 2009, a retrospective review was performed for the prospectively collected 143 patients who were diagnosed with breast cancer. All the patients received a conventional imaging examination and BSGI before definitive surgery. The patients underwent BSGI with intravenous injection of 30 mCi of 99mTc-sestamibi through the contralateral antecubital vein. After 10 minutes, the craniocaudal and mediolateral oblique images were obtained. All the imaging findings were correlated with the final pathologic examination. Results: The mean age of the patients was 49.7±9.4 years (range, 27-77). In 143 patients, 166 malignant lesions were identified by pathologic examination (invasive cancer: 96 (67.1%), ductal carcinoma in situ 14 (9.8%) and invasive cancer with carcinoma in situ 33 (23.1%). The conventional imaging modalities found 166 malignant lesions and BSGI found 156 malignant lesions. The rate of correspondence was 94.0% between the conventional imaging modalities and BSGI for malignant lesions. For BSGI, there were 4 false positive findings and 10 false negative findings. BSGI found no occult cancers that were missed by conventional imaging modality. For making the diagnosis of axillary lymph node metastasis, the sensitivity, specificity and accuracy were 33.3%, 92.1%, and 69.9% for BSGI, and 55.6%, 77.5%, and 69.2%, for ultrasonography, respectively. Conclusion: BSGI may have the potentiality to make a correct diagnosis in breast cancer patients. However, in this study, it seems that BSGI is not superior to conventional imaging modalities. BSGI is not a standard method to evaluate breast cancer lesions before surgery.