99mTc-MIBI scintimammography as a complement of the mammography in patients with suspected breast cancer. A multicentre experience.

The aim of this work has been to evaluate the clinical usefulness of 99mTc-MIBI scintimammography, used as a complement to mammography, in the study of patients with suspected breast cancer. We performed prone breast scintigraphy in 253 patients (268 lesions) with suspected breast cancer. The size and degree of the suspected breast cancer was evaluated by mammography. Diagnosis was established by biopsy. Malignancy was diagnosed in 155 lesions and benign diseases in 113. The results of the scintimammography were a sensitivity of 91%, a specificity of 71%, PPV=81% and NPV=85%. In lesions smaller than 1 cm, sensitivity and specificity were 57% and 100%; in lesions with a diameter of between 1 and 2 cm, these figures were 90% and 72% respectively, and in lesions of more than 2 cm the sensitivity was 99% and the specificity 50%. On mammography, 155 lesions were considered as having a high suspicion of malignancy, whilst 72 were indeterminate and 41 had a low probability. In lesions with a low or indeterminate suspicion of malignancy on mammography, the sensitivity and NPV of the scintimammography were 97% and 98%. Scintimammography is a useful technique in the study of lesions where breast cancer is suspected. Scintimammography results are closely related to tumour size and the degree of mammographic suspicion. Scintimammography can be useful where mammography identifies lesions with a low or indeterminate suspicion of malignancy.