Combined 68Ga-NOTA-Evans Blue Lymphoscintigraphy and 68Ga-NOTA-RM26 PET/CT Evaluation of Sentinel Lymph Node Metastasis in Breast Cancer Patients.

In this study, we applied a new strategy to identify sentinel lymph node (SLN) metastasis by combining 68Ga-NOTA-Evans Blue (68Ga-NEB) for SLN mapping and 68Ga-NOTA-RM26 for LN metastasis detection in breast cancer patients. A total of 24 female patients with breast cancer diagnosed by core biopsy or suspected by mammography or ultrasonography were recruited and provided informed consent. All patients underwent 68Ga-NEB and 68Ga-NOTA-RM26 PET/CT imaging. Visual analysis of 68Ga-NEB PET/CT images was used to determine SLNs, and then compared with the 68Ga-NOTA-RM26 results and histopathological findings. SLNs were visualized in 24 of 24 patients (100.0%) within 4.0-10.0 (5.6 ± 1.4) min. All patients were pathologically diagnosed with breast cancer, and 12 patients had ipsilateral lymph node metastasis. By combining 68Ga-NEB and 68Ga-NOTA-RM26 images, 7/12 (58.3%) patients showed mild to intense uptake of 68Ga-NOTA-RM26 in SLNs, 1/12 patient (8.3%) had moderate uptake of 68Ga-NOTA-RM26 in the non-SLNs rather than SLN, indicating possible bypass lymphatic drainage, partially accounting for the false negatives in SLN biopsy during surgery. No false positives were found. The SUVmax of 68Ga-NOTA-RM26 activity in metastatic SLNs was significantly higher than that in non-metastatic SLNs (2.2 ± 2.3 vs 0.7 ± 0.1, P = 0.047). This study manifests the value of combination of 68Ga-NEB and 68Ga-NOTA-RM26 dual tracer PET/CT in preoperative evaluation of SLN metastasis in breast cancer patients, especially in those patients with lymphatic obstruction and bypass drainage. In general, positive 68Ga-NOTA-RM26 uptake in either SLN or other lymph nodes can apply lymph node dissection rather than intraoperative SLN biopsy.