[Gammography using Tc 99m MIBI in patients with suspected breast cancer. Proposed diagnostic protocol]

The aim of this work has been to determine whether the joint use of mammography and scintimammography is capable of reducing the number of biopsies required in patients with suspected breast cancer. We have performed scintimammography in 90 patients, 97 lesions, with breast cancer suspicion. In the mammography was evaluated the degree of malignancy suspicion and the size of the lesion. Only 41 of the biopsies revealed the presence of cancer. The sensitivity, specificity, PPV and NPV of scintimammography were 85%, 79%, 74% and 88%. According to the mammography findings 20 lesions (1 breast cancer) were included as low, 31 lesions (4 breast cancer) as indeterminate and 46 lesions (36 breast cancer) as high malignancy suspicion. 14 lesions (2 low, 2 indeterminate and 10 high suspicion) were smaller than 1 cm. The scintimammography was positive in all breast cancer of low and indeterminate suspicion of malignancy and in 30 of high probability. On the basis of this results we propose that a biopsy must be carried out to those lesions with a high suspicion of malignancy, and to lesions with low or indeterminate suspicion that are smaller than 1 cm or that present a positive scintimammography. Following this protocol, only 64 of the 97 biopsies would have been necessary, with a reduction of the 34% in the total number of biopsies and, more important, a 65% of reduction in the number of biopsies carried out in the groups of low and indeterminate suspicion of malignancy. At the same time we would indicate biopsy in all cases of breast cancer.