METASTATIC AXILLARY LYMPH-NODE TECHNETIUM-99M-MIBI IMAGING IN PRIMARYBREAST-CANCER

Technetium-99m-MIBI scintimammography has been shown to be useful in t he detection of primary breast cancer. The purpose of this study was t o evaluate the potential role of scintimammography in detecting axilla ry lymph node involvement in patients undergoing scintimammography to detect primary breast cancer. Methods: A group of 100 women with breas t cancer who were scheduled for a Level I-II axillary dissection were prospectively studied. Scintimammography was performed in all patients before histopathologic confirmation of breast cancer. Two lateral (pr one imaging) views and one anterior (supine) planar thoracic view were obtained 10-15 min after the injection of 25-30 mCi Tc-99m-MIBI (10 m in/view) by using a special breast positioning device (foam cushion) p laced over the imaging table. Both of the axilla were included in the field-of-view. Two experienced blinded observers reviewed all cases bo th from films and from the computer screen with contrast adjustment wh en needed. The site of intravenous injection of 99m-MIBI was known to the interpreters in order to avoid reading any false-positive uptake i n the axilla ipsilateral to the injection site. Results: A total of 52 patients had no axillary lymph node involvement (611 negative nodes) while 48 patients had at least one axillary lymph node with metastatic involvement (180/502 positive nodes). The sensitivity of scintimammog raphy in detecting metastatic axillary lymph node involvement was 79.2 % (38/48), and the specificity was 84.6% (44/52). The positive and the negative predictive values were 82.6% (38/46) and 81.5% (44/54), resp ectively. Conclusion: This study shows that scintimammography has good diagnostic accuracy for detecting axillary lymph node involvement in patients with breast cancer. This information should be added to the r esult of standard scintimammography, which requires very minor modific ations in order to simultaneously evaluate both oi the axilla.