Technetium-99m-sestamibi mammoscintigraphy in suspected breast cancer. Radiologic and histologic correlations in 43 surgically treated patients

Background: Breast cancer and non-palpable breast lesions incidence are growing and mammography failed to detect at least 10% of malignancy, especially in fatty, dense and abnormal breast. Many alternative studies have been tested and mammoscintigraphy with 99mTc-sestamibi showed interesting posslbllltles. The aim of this study was to determine sensitivity and specificity of mammoscintigraphy in identifying breast cancer and its usefulness in differential diagnosis. Patlents and Methods: We retrospectively analysed 43 female patients with a median age of 56 years (range 32 - 86 years). Fifteen (33.3%) patients were in pre- or perimenopausal and 30 patients were postmenopausal. Fine needle aspiration biopsy (FNAB) showed malignancy in 38 patients and atypical ductal hyperplasia or complex sclerosing lesions in 5 patients, while 37/41 (90.2%) patients had mammographic signs of cancer or abnormalities. All patients received 20 mCl99mTc-sestamibi intravenously and underwent mammoscintigraphy and two lateral and one or two anterior planar images were obtained by a single head gamma camera equipped with high-resolution collimator. Results: All patients underwent surgery and in 39 (90.7%) cases a histologically confirmed breast cancer was found. At pathological examination the size of the tumor ranged from 6 to 50 min (median 15 mm) and in 6 (15.4%) patients with nonpalpable lesions it was excised under stereotactic guidance requiring a wire needle localization and subsequent histologically confirmed diagnosis before definitive surgical treatment. Mammography, FNAB and mammoscintigraphy showed sensitivity of 84.6%, 97.4% and 76.9% respectively. Five of the 9 tumors undetected by scan were nonpalpable and in only two cases there were mammographic diagnosis of cancer. In 4 patients (10.2%) both mammoscintigraphy and mammography had false negative results and the overall sensitivity resulted of 89.7%, while FNAB showed true positive results in 3 of these patients. We observed 100% sensitivity with each technique. Conclusions: This preliminary study confirm the role of 99mTc-sestamibi mammoscintigraphy in early and mammographycally undetected breast cancer as additional and maybe necessary noninvasive procedure. In patients with suspected or abnormal FNAB requiring excisional biopsy it can helpful in surgical planning.