Specificity of radiographic lymphadenopathy for lymph node metastasis in renal cell carcnioma.

Abstract

442 Background: Approximately 30% of patients with renal cell carcinoma (RCC) will have metastatic disease at the time of diagnosis. Patients without preoperative lymphadenopathy (LAD) radiographically rarely have positive nodes at the time of nephrectomy. We sought to evaluate the specificity of radiographic LAD for lymph node metastases in patients with and without clinical metastatic RCC. Methods: We retrospectively reviewed all nephrectomies performed at our institution from 2003-2013. We identified patients with clinical stage classification T2-T3 (cT2-T3) RCC and stratified patients by clinical N and M classification. Lymphadenectomy was performed at surgeon discretion. Performance statistics for preoperative imaging for pathologic lymph node metastases and multivariable logistic regressions models to identify patient characteristics associated with lymph node metastases were generated. Results: A total of 223 patients were identified. Of these, 85 (38%) had clinical evidence of metastatic disease while 138 (62%) did not. In patients with clinical metastatic disease, LND was performed in 68%; of those without clinical metastatic disease, LND was performed in 48%. Radiographic LAD for those with clinical metastatic disease (26/85 patients, 31%) had sensitivity of 94%, specificity of 49%, positive predictive value (PPV) of 43%, and negative predictive value (NPV) of 95% for pathologically confirmed lymph node involvement. Radiographic LAD for patients without clinical metastatic disease (37/138 patients, 27%) had sensitivity of 90%, specificity of 52%, PPV of 25%, and NPV of 96% for pathologically confirmed lymph node involvement. On multivariate logistic regression analysis (adjusted for age, gender, smoking status, obesity, non-clear cell histology, and grade) having clinical metastatic disease was significantly associated with pathologic node positivity (RR = 3.37, 95% CI 1.19 – 20.6). Conclusions: Radiographic lymphadenopathy is a nonspecific finding in patients with RCC and LND is not routinely performed at our institution. However, in the setting of clinical metastatic disease, radiographic LAD is more likely to represent pathological lymph node metastases.