Technetium-99m-sestamibi prone scintimammography to detect primary breast cancer and axillary lymph node involvement

The purpose of this study was to evaluate prospectively the sensitivity and specificity of scintimammography in the detection of both primary breast cancer and axillary lymph node involvement.

Sixty-five consecutive women referred for a suspicious breast lesion on clinical examination and/or with abnormal mammographies suggestive of malignancies were studied with scintimammography using planar prone imaging (with a chest positioning device with semicircular lateral aperture on the imaging table) performed 15 min postinjection of 25-30 mCi 99mTc-sestamibi. Three planar views, right and left lateral prone and anterior supine thoracic views, were obtained (8-10 min/view). The entire breast and ipsilateral axillary region were included in the field of view. Excisional breast biopsy and/or fine needle aspiration cytology were performed in all patients within 4 wk after scintimammography. Axillary node dissection was also performed.

The largest primary tumor measured 2 x 3 cm. There were 47 primary breast cancers (8 different histologic types) and 18 benign breast lesions (5 histologic types). The sensitivity of scintimammography for detecting primary breast cancer was 91.5% (43 true-positive, 4 false-negative) and the specificity was 94.4% (17 true-negative, 1 false-positive). Metastatic axillary lymph node involvement was seen in 19 of 41 patients. The sensitivity of scintimammography to detect metastatic lymph nodes was 84.2% (16 true-positive, 3 false-negative) and the specificity was 90.9% (20 true-positive, 2 false-positive).

This preliminary study confirms the results of some previous reports, which showed the high diagnostic accuracy of scintimammography in detecting breast cancer. This study also shows the potential value of this procedure to detect axillary lymph node involvement as concomitant information.