SCINTIMAMMOGRAPHY WITH TC-99M METHOXYISOBUTYLISONITRILE - RESULTS OF A PROSPECTIVE EUROPEAN MULTICENTER TRIAL

The aim of the trial was to determine the diagnostic accuracy of scint immammography with technetium-99m methoxyisobutylisonitrile (Tc-99m-MI BI) in the detection of primary breast cancer and to verify its clinic al usefulness. A total of 246 patients with a suspicious breast mass o r positive mammogram were included in this prospective European multic entre trial. At 5 min and 60 min (optional) p.i. two lateral prone ima ges were acquired for 10 min each; 30 min p.i. one anterior image was acquired for 10 min. There were 253 lesions (195 palpable and 58 non-p alpable), in respect of which histology revealed 165 cancers and 88 be nign lesions. Institutional and blinded read results were correlated t o core laboratory histopathology results obtained during excisional bi opsy. Diagnostic accuracy for the detection of breast cancer was calcu lated per lesion. The overall sensitivity and specificity of blinded r ead scintimammography were 71% and 69%, respectively. For palpable les ions, the sensitivity of blinded read and institutional read scintimam mography was 83% and 91%, respectively. Sensitivity was not dependent on the density of the breast tissue. Invasive ductal and invasive lobu lar cancers showed similar sensitivity. The sensitivity and specificit y of mammography were 91% and 42%, respectively, and did not depend on the tumour size. In 60% of false-negative mammograms, Tc-99m-MIBI was able to diagnose malignancy (true-positive). High-quality imaging wit h Tc-99m-MIBI has a high diagnostic accuracy for the detection of prim ary breast cancer. Used as a complementary method, scintimammography w ith Tc-99m-MIBI can help to diagnose breast cancer at an earlier stage in patients with dense breasts.