Background: The advantages and disadvantages of technetium Tc 99m tin colloid and technetium Tc 99m phytate as tracers for sentinel node (SN) identification in patients with clinical stage I non-small cell lung cancer were examined retrospectively.
Methods: Sentinel node identification was conducted using tin colloid and phytate, respectively, in 73 and 74 patients with clinical stage I non-small cell lung cancer. We compared these two tracers in terms of identification rates, numbers of SNs, characteristics of patients whose SNs could not be identified, and the pathologic results of SNs.
Results: The tin colloid tracer identified SNs in 54 of the 73 patients (74%), which was significantly lower than the 89% (66 of 74 patients) in the phytate group (p = 0.02). The number of SNs per patient was 1.7 +/- 0.8 in the tin colloid group, which was significantly less than the 2.4 +/- 1.5 in the phytate group (p = 0.002). Although patients in the tin colloid group whose SNs could not be identified had a significantly lower forced expiratory volume in 1 second to forced vital capacity ratio than those whose SNs could be identified (p = 0.04), the phytate group did not show such a difference. Eleven of 120 patients whose SNs could be identified had pathologic N1 or N2 disease, but neither group showed any false-negative results for SN identification.
Conclusions: Both tin colloid and phytate are reliable tracers for identifying SNs in non-small cell lung cancer. The advantage of phytate is that SNs can be detected more frequently than with tin colloid, even in patients with a low forced expiratory volume in 1 second to forced vital capacity ratio. However, tin colloid requires fewer nodes than phytate to identify SNs.