TC-99M-TETROFOSMIN SCINTIMAMMOGRAPHY - A PROSPECTIVE-STUDY IN PRIMARYBREAST-LESIONS

Despite low specificity routine mammography is the method of choice to screen women for breast cancer. In addition high frequency ultrasonog raphy (US) or magnetic resonance imaging (MRI) can improve breast canc er diagnosis. However there is a lack of conventional imaging to impro ve the high rate of false positive results that make biopsy or surgery necessary. Aim: The purpose of our study was to evaluate prospectivel y the sensitivity specificity, PPV and NPV of scintimammography with a new cationic complex Tc-99m-tetrofosmin. Methods: Fourtyeight patient s in whom mammography and/or high resolution ultrasonography (10MHz) r evealed suspicious breast lesions were studied with Tc-99m-tetrofosmin scintimammography. In thirtyfour of them biopsy and/or surgery was pe rformed for histological evaluation. After intravenous injection of 55 5 MBq Tc-99m-tetrofosmin dynamic images over three minutes (1 frame/10 sec.) planar images in anterior and lateral projections (5 min. p.i.) and SPECT imaging including 3-D-reconstruction (20 min. p.i.) were pe rformed. Scintimammography was evaluated as negative, equivocal (+), p robably (++) or definitely (+++) positive. Results: Scintimammography with Tc-99m-tetrofosmin was negative in 18 patients (17 t.n.; 1 f.n.) and positive in 16 patients (10 t.p., 6 f.p.). The false negative scin timammography was observed in a patient with infiltrating ductal carci noma pT1, the false positive result in a patient with fibrocystic dise ase; all of the five fibroadenomas were also ''false'' positive. Sensi tivity of Tc-99m-tetrofosmin scintimammography in this prospective stu dy was 91%, specificity 74%, PPV 63% and NPV 94%. Scintimammographic r esults in patients with suspicious breast lesion show, that Tc-99m-tet rofosmin accumulates in breast cancer as well as in fibroadenoma. Howe ver the high NPV of 94% excludes breast cancer in suspicious mammograp hic lesions in a very high degree and therefore reduces the need of bi opsy and/or surgery in most of these patients. Conclusion: Our first r esults show that scintimammography with Tc-99m-tetrofosmin might play a role as further diagnostic step before surgery for women in whom mam mography and/or ultrasonography show suspicious lesions.