Feasibility of sentinel lymph node mapping in renal cell carcinoma using intraoperative radiotracer injection

Introduction: The applicability of sentinel lymph node biopsy for early detection of metastasis in patients with renal cell carcinoma (RCC) is still in the validation phase and under investigation, which might be due to the unpredictability of the lymphatic pattern in RCC. In this study, we aimed to evaluate the feasibility and accuracy of sentinel node biopsy in patients with renal masses. Methods: In this prospective study, twenty-one candidates for open radical nephrectomy with T1-T3 renal tumors, were included consecutively. Sentinel nodes were sought using a hand-held gamma probe following the injection of radiotracer. The validity of sentinel node biopsy procedure as our index test was compared with lymphadenectomy as the standard method for staging and detecting the regional lymph nodes metastasis. Results: At least one sentinel lymph node was detected in thirteen of the patients using a hand-held gamma probe, and the detection rate was 61%. There was no patient with positive pathological involvement of the regional lymph nodes despite the negative involvement of the sentinel lymph node; so, the false-negative rate was 0%. Conclusion: Although sentinel lymph node biopsy was feasible in patients with RCC, sentinel node detection failure was high in our study. More prospective studies with a larger sample size are needed for standardization of the radiotracer injecting aspects and mapping method to increase the detection rate and to evaluate the false negative rate more accurately.