Abstract: Objective To compare the accuracy of intaoperative methylene blue alone and in combination with 99mTc-sulfur
colloid isotopic tracing for detection of sentinel lymph nodes (SLNs) in early-stage non-small cell lung cancer (NSCLC).
Methods Sixty-one patients with operable NSCLC who did not receive previous radiotherapy or chemotherapy were enrolled.
Methylene blue and 99mTc-sulfur colloid were injected into the subserosal layer adjacent to the tumor, and SLNs were defined as
those with blue staining or those containing 3 times more radioactivity than the surrounding tissue detected with a gamma
probe. The SLN were removed with systematic lymph node dissection. All the removed lymph nodes were examined
histopathologically with HE staining and immunohistochemistry. Results Methylene blue alone showed a low detection rate
(60.0%) and sensitivity (58.33%) for SLNs compared with the combination of methylene blue and isotope tracing (96.15% and
92.86%, respectively). Conclusion The combination of methylene blue and 99mTc-sulfur colloid isotopic tracing allows accurate
detection of the SLNs in early-stage NSCLC.