DETECTION OF AXILLARY LYMPH-NODE METASTASIS OF BREAST-CARCINOMA WITH TC-99M SESTAMIBI SCINTIMAMMOGRAPHY

Several investigators have advocated management of breast cancer patie nts without axillary dissection, obviating the morbidity associated wi th this procedure. Approximately 30-40 per cent of all patients with b reast carcinoma will have lymph node metastasis. Axillary dissection o ffers no therapeutic benefit to node-negative patients, and it may lea d to unnecessary morbidity. It is apparent that a noninvasive test to determine the presence of axillary metastases may obviate the need for axillary dissection. The aim of this study was to determine the role of scintimammography (SMM) with technetium-99m sestamibi in the detect ion of axillary node metastasis in breast carcinoma. Thirty-one women with the diagnosis of breast carcinoma who had SMM and axillary lympha denectomy were included. SMM was done following an intravenous injecti on of 20 mCi of Tc-99m sestamibi. Planar scintigraphic imaging was acq uired in a lateral prone and an anterior view of the breasts for the e valuation of the axilla. SMM scans were interpreted by two nuclear med icine physicians blinded to the clinical presentation and histologic r esults. The correlation of SMM with histologic assessment showed a sen sitivity of 75 per cent, specificity of 82 per cent, positive predicti ve value of 88 per cent, and negative predictive value of 64 per cent. The interobserver correlation of SMM interpretation between the two n uclear medicine physicians showed good agreement, with kappa = 0.49. C onsistency in the interpretation of Tc-99m SMM was obtained when two i ndependent radiologists reviewed the studies. Based on these data, we are unable to show that SMM is a reliable test for the detection of ax illary metastases in patients with breast cancer. However, a high posi tive value of 88 per cent is encouraging and deserves further study.