PRONE SCINTIMAMMOGRAPHY IN PATIENTS WITH SUSPICION OF CARCINOMA OF THE BREAST

Mammography and physical examination have a sensitivity of 85 percent for detection of carcinoma of the breast. Mammography also has a posit ive predictive value of 15 to 30 percent. The aim of this study was to evaluate the usefulness of scintimammography (SMM) as a screening tec hnique for the detection of carcinoma of the breast and compare the te st's sensitivity and specificity with that of mammography. We conducte d SMM on 59 female patients in whom abnormal mammogram and physical ex amination warranted biopsy of the breast or fine needle aspiration cyt ology of the breast, or both. Each patient received 20 millicuries of Tc-99m Sestamibi intravenously. Five and sixty minutes postinjection, planar breast images in lateral and posterior oblique views were obtai ned. In 23 patients with biopsy-confirmed carcinoma of the breast, the SMM result was positive. In 33 patients with benign breast lesions, n o increased uptake of Sestamibi was noted in the breast. Five other pa tients with benign lesions of the breast had false-positive scans. The re was one patient with an intraductal carcinoma and a cluster of micr ocalcifications on mammography without an associated mass, for whom th e Tc-99m Sestamibi scan was negative. In the group of patients studied , the sensitivity of SMM was 95.8 percent, specificity was 86.8 percen t, positive predictive value was 82.1 percent and, most importantly, t he negative predictive value for the detection of carcinoma of the bre ast was 97.1 percent. We conclude in this pilot study that SMM is a hi ghly sensitive test that improves the specificity of conventional mamm ography for the detection of carcinoma of the breast and deserves furt her study as a screening technique to potentially reduce the number of mammographically ''indicated'' biopsies of the breast that yield nega tive results for carcinoma.