RESUMO
The purpose of this study was to evaluate the role of scintimammography (SMG) and ultrasound (US) in early diagnosis of breast cancer. SMG was administered to 32 women with breast lesions of less than 1 cm in diameter. In addition, all patients underwent high frequency US imaging with digital wide field of view. The following US features were set as diagnostic: heterogeneous echo pattern, irregular morphology, hyperecho, poorly defined edges, posterior acoustic attenuation. SMG was performed in planar and tomography modes 15 min. after i/v injection of 740-860 MBq 99mTc-sestamibi. Images with focal and scattered patchy uptake were discarded. Data on all lesions were verified by biopsy and/or surgery. Thirty-six women revealed lesions of less than 1 cm: 12 out of 14 cases of breast cancer had them, while malignancy was not detected in 16 of 21 women with benign breast lesions. Sensitivity (Sen), Specificity (Sp) and Accuracy (Ac) of SMG in this group was as follows: 86%, 76% and 80%, respectively. US examinations in this group diagnosed benign lesions in 27 out of 35 women: 21--negative, 6--false negative. In the remaining 8 cases, US findings on breast cancer were positive: Sen was low (57%), Sp--high (100%) and Ac--moderate (82%). Taking into account that SMG represents functional status of breast lesions while US--anatomical one, we tested diagnostic value of their combination too (US+SMG). Cancer diagnosis was passed when either SMG or US revealed abnormalities. This diagnostic strategy featured outstanding Sen (100%), moderate Sp (76%) and Ac of 82%. It may be concluded that the combination procedure seems highly promising as far as early diagnosis of small (< 1 cm) breast cancers are concerned.
