Background: In a prospective study we evaluated the accuracy, sensitivity, and specificity of single-photon-emission computed tomography (SPECT) technetium-99m (99Tcm) sestamibi scintimammography to differentiate between benign and malignant small solid lesions of the breast, and to diagnose axillary node involvement in patients with small breast tumors.
Methods: We prospectively evaluated 172 women with a solid lesion of the breast less than 3 cm in diameter and no evidence of axillary lymph node involvement on physical examination, ultrasound, and mammography. Thereafter, all patients underwent excision of the lesion, and, if pathology was positive for cancer, quadrantectomy and axillary lymph node dissection independently by the results of scintimammography.
Results: There were 92 patients with a benign lesion and 80 patients with cancer. SPECT scintimammography correctly identified all 80 patients with cancer; there were six false-positive cases and no false-negative cases for a test efficacy of 96.5%, sensitivity of 100%, and specificity of 93.5%. Forty-five of the 80 patients with cancer had axillary lymph node involvement and scintimammography correctly identified 39 of the 45 patients. There was one false-positive case and six false-negative cases for a test efficacy of 90%, sensitivity of 86.4%, and specificity of 97.5%.
Conclusion: SPECT scintimammography should be considered selectively in the preoperative evaluation of patients with small solid lesions of the breast. It allows correct identification of patients with cancer and identification of a significant number of patients with axillary lymph node involvement.