Axillary lymph node Metastases detection with 99mTc-sestamibi scintimammography in patients with breast cancer undergoing curative surgery

Background: Axillary lymph node (AN) status is the primary prognostic discriminant in patients with breast cancer (BC). Although axillary dissection represents the method of choice for obtaining such information, less invasive procedures have been suggested. The aim of this study was to evaluate the usefulness of Tc-99m-sestamibi scintimammography (SSM) in detecting AN involvement in patients with confirmed primary BC undergoing surgery. Patients and Methods: A series of 159 consecutive women (median age 54 years, range 36-78 years) with confirmed BC undergoing curative surgery were enrolled in the study. Each patient underwent SSM, from 4 to 12 days prior to surgery. According to the tumour staging, modified radical mastectomy was performed in 41 (25.8%) patients, while 118 (74.2%) patients underwent breast conserving surgery with dissection of the axilla. The results of SSM were compared against the final histological evaluation of the axillary nodes. Results: The final pathology showed 33 (20.8%) pT1b, 90 (56.6%) pT1c, and 36 (22.6%) pT2 breast carcinomas. The greatest diameter of the tumour ranged from 8 to 30 mm (median 16 mm). Sixty patients (37.7%) had axillary node metastases (N1), and 99 (60.3%) had negative nodes (NO). The age of the patients significantly correlated with both size of the tumour (R=0.24, p<0.01) and number of positive nodes (R=0.33, p<0.01). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of SSM in detecting AN metastases were 81.4%, 91.0%, 84.2%, 91.0% and 87.4%, respectively. The sensitivity was higher in patients with three or more positive nodes (27 out of 28, 96.4%), while in patients with two (n=25) or one (n=7) positive nodes, the sensitivity decreased to 80% and 28.60%, respectively. Conclusion: SSM may be useful in patients undergoing surgery for BC when a preoperative assessment of axillary lymph node status is required. Unfortunately, the sensitivity of SSM in detecting node metestases in patients with BC is low when the number of involved nodes is two or less. This suggests that other imaging techniques should be used is conjunction with SSM, with the aim of increasing both sensitivity and specificity.