Aim: The aim of the present study was to determine the accuracy of single-photon emission computed tomography-computed tomography (SPECT-CT) with technetium-99m-sestamibi (Tc-MIBI) for detecting multiple (>2 nodes) axillary lymph node involvement in patients with breast cancer (BC).
Patients and methods: A total of 184 women with BC were examined. Clinically, axillary lymph nodes were classified as N0 in all cases. Patients underwent SPECT-CT breast and axillary region imaging 10-15 min after a 740 mBq intravenous injection of Tc-MIBI. SPECT-CT data were then verified by definitive histopathological examination (sentinel-node biopsy and/or axillary lymph node dissection were used as reference standard). Diagnostic values of different CT and SPECT signs of multiple (>2) lymph node involvement were evaluated.
Results: Histological examination of excised lymph nodes showed metastatic involvement in 62 (33.7%) out of 184 patients. In fact, 25 (13.6%) patients had more than two lymph node involvements. In another 37 (20.1%) cases the metastasis was revealed in one or two sentinel lymph nodes only. The main SPECT-CT criteria of multiple (>2) lymph node involvement were as follows: the maximum size of the primary tumor (>20 mm), lymph node dimensions (>12 mm along the long axis and >10 mm along the short axis), nodal cortical thickness (>4 mm), round shape, solid structure, quantity of identified abnormal lymph nodes (>1), and intensity of tracer uptake. The developed integrated model offers the possibility to exclude multiple lymph node metastasis (>2) in BC patients with a probability of 99%.
Conclusion: This single-center study showed that in patients with BC, a combination of functional and anatomical data that were obtained by using SPECT-CT with Tc-MIBI can significantly improve detectability of multiple (>2) axillary metastases.