Sentinel node mapping for early breast cancer patients using 99mTc-phytate: Single center experience on 165 patients

Introduction: Several radiotracers are being used for sentinel node mapping in patients with breast cancer. In the current study, we reported our experience with 99m-Tc Phytate for sentinel node mapping in Mashhad University of Medical Sciences. Methods: All breast cancer patients who underwent sentinel node mapping using 99m-Tc Phytate were included. All patients received intradermal peri-areolar injection of 0.5 mCi/0.1cc 99m-Tc Phytate. Lymphoscintiraphy was performed for 145 patients 5-10 minutes post-injection. The sentinel nodes were found during surgery using a hand-held gamma probe as well as blue dye technique. Results: In total 165 patients were evaluated. Lymphoscintigraphy showed axillary sentinel nodes in 135 out of 145 patients (93%) following imaging. At least one sentinel node could be detected in all these 135 patients during surgery. In the remaining 10 patients with sentinel node non-visualization, 5 had sentinel node harvesting failure during surgery. Median number of sentinel nodes on the lymphoscintigraphy images was 1. Sentinel node detection rate was 95% (157/165). In the 8 patients with sentinel node harvesting failure, 7 had pathologically involved axilla. Median number of harvested sentinel nodes was 1. Mean sentinel node to background count ratio was 10±2. Conclusions: 99m-Tc Phytate is an effective and highly successful radiotracer for sentinel node mapping. Sentinel node can be visualized in a short time after 99m-Tc Phytate injection on the lymphoscintigraphy images. The sentinel to background count during surgery is high which results in more convenient sentinel node harvesting and high detection rate.