(99M)Technetium-sestamibi scintimammography in non-palpable breast lesions found on screening X-ray mammography

The sensitivity and specificity of (99m)Tc-sestamibi scintimammography in patients with non-palpable breast lesions diagnosed by screening mammography and the value of (99m)Tc-sestamibi to detect axillary lymph node metastases was determined.

Between September 2000 and December 2003, 103 females with non-palpable breast lesions were included for further evaluation. X-ray mammography was repeated and 99mTc-sestamibi scintimammography performed within one-week. Anterior, and left and right lateral images were obtained. The scintimammography was analysed by 2 experienced observers who were blinded to the clinical, pathological, and radiological results. The sensitivity and specificity of scintimammography to diagnose non-palpable lesion(s), including the axillary regions, was compared with histopathology, clinical, and radiological follow up.

Two patients (one non-small lung cancer and one non-Hodgkin's disease) were excluded. Both showed (99m)Tc-sestamibi avid lesions in the breast and axillary region. In the remaining 101 patients, 37 true positive (TP), 4 false positive (FP), 52 true negative (TN), and 8 false negative (FN) breast carcinomas were found. The specificity was 92.8%, sensitivity 82.2%, positive predictive value (PPV) 90.2%, and negative predictive value (NPV) 86.6%. (99m)Tc-sestamibi scintimammography showed axillary lesions in 5/15 (33%) patients with axillary lymph node metastasis.

In patients with non-palpable lesions diagnosed by screening- X-ray-mammography, (99m)Tc-sestamibi scintimammography provided high specificity and PPV. Furthermore, (99m)Tc-sestamibi scintimammography detected 33% of patients with axillary lymph node metastases. Therefore, (99m)Tc-sestamibi scintimammography could be of incremental value in the surgical work-up of these patients.