Contribution of 99mTc-MIBI scintimammography to the diagnosis of non-palpable breast lesions in relation to mammographic probability of malignancy.
The low positive predictive value of mammography results in unnecessary biopsies. We present a prospective evaluation on the contribution of 99mTc-MIBI Scintimammography (SMM) to the diagnosis of breast cancer in 41 patients with non-palpable breast lesions detected by mammography. In all cases mammographical findings were indicative of biopsy and according to the probability of malignancy they were classified into three groups: high probability (17), intermediate (15), and low (9). There were 22 malignant lesions and 19 benign. In the high probability group. MIBI-SMM changed the only false positive into true negative, and showed 2 false negatives. In the intermediate group, MIBI-SMM changed 7 of 11 false positives on mammography into true negatives, and showed 1 false negative. In the low probability group MIBISMM changed 3 of the 7 false positive into true negatives without false negatives. In the 24 patients included in the intermediate and low probability groups, 10 of the 18 false positives were changed into true negatives by MIBI-SMM at the expense of 1 false negative. The addition of SMM may to reduce up to 55% of the number of unnecessary biopsies in non-palpable breast lesions.