Usefulness of 99m-Tc-sestamibi scintimammography in suspected breast cancer and in axillary lymph node metastases detection

Aims: To evaluate the usefulness of 99m-Tc-sestamibi scintimammography (SSM) in the detection of T1-2, N0-1, M0 breast cancer (BC) and axillary node (AN) metastases. Patients and methods: A series of 239 women (median age 55 years) who had already been selected for breast biopsy underwent both mammography (MG) and SSM before surgery. The final diagnosis confirmed in 207 (86.6%) patients, and benign breast lesions in 32 (13.4%). Results: Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MG and SSM in BC detection were 88.9% vs 87.9%, 62.5% vs 93.8% (P<0.01), 93.9% vs 98.9%, 46.5% vs 54.5%, and 85.4% vs 88.7%, respectively. Age did not affect (P=NS) SSM sensitivity, and in premenopausal patients (n=80 (33.5%)) its specificity was 100%. Overall sensitivity and specificity of SSM for assessing AN involvement were 82.3% and 94.1%, respectively. In patients with <3 AN metastases (n=33 (53.2%)) SSM sensitivity was 69.7%, and only one out of six patients with a single AN metastasis had a positive scan. Conclusions: In patients with suspicious MG undergoing biopsy, SSM should be considered before surgery because of its high specificity, especially in younger patients. At present, its usefulness in detection of AN metastases is still modest and does not allow a correct pre-operative staging of patients with BC.