Intraoperative sentinel lymph node identification using novel receptor binding agent (technetium-99m neomannosyl human serum albumin, 99mTc-MSA) in stage I non-small cell lung cancer

Abstract

7588 Background: In order to simplify synthesis and labelling procedures and to improve the biological properties, we developed a novel mannose receptor-binding agent, Technetium-99m neomannosyl human serum albumin (99mTc-MSA). This study was designed to test the reliability and feasibility of sentinel nodes identification using this new radioactive agent in stage I non-small cell lung cancer. Methods: A total dose of 1mCi of 99mTc- MSA in 0.2ml was administered in one shot at the peri-tumoral region under the chest CT or bronchoscope guidance 3 hours before surgery in the CT room. Dynamic whole-body SPECT lymphoscintigraphic image was obtained at 30 min after injection and static thoracic SPECT lymphoscintigraphy images were acquired at 1 and 2 hour after injection. During operation, the radioactivity of the lymph nodes was counted with a handheld gamma probe before (in vivo) and after (ex vivo) dissection. Lymph nodes with an ex vivo radioactive count more than 5 times the radioactivity count of the resected lung tissue were identified as sentinel nodes. The correlation between the in vivo and ex vivo results was examined. All harvested lymph nodes were examined histologically. Results: Thirty patients (20 men, 10 women; mean age, 62.6±9.40 years) who were candidates for lobectomy with mediastinal lymph node dissection for stage I non-small cell lung cancer were enrolled consecutively. Sentinel nodes could be detected from 30 minutes to 5 hours after the injection of 99mTc-MSA on lymphoscintigraphy. The mean number of dissected lymph nodes per patients was 20.7±1.30 (8∼41). Among 30 patients, sentinel lymph nodes could be identified in all patients (100%). The mean number of sentinel lymph nodes identified was 2.4±1.04 stations (range, 1∼5) per patient. No false-negative sentinel lymph nodes were detected in any of the 8 patients with N1 or N2 disease (0%). The relationship between in vivo and ex vivo results for mediastinal sentinel lymph nodes showed concurrence in 25 of 30 patients (83.3%). Conclusions: The results of this clinical trial showed that 99mTc-MSA had promising properties for sentinel nodes identification in non-small cell lung cancer. No significant financial relationships to disclose.