Prognostic Value of Positive Lymph Nodes in Patients with Renal Cell Carcinoma and Tumor Thrombus Undergoing Nephrectomy and Thrombectomy

Abstract

<b><i>Introductions:</i></b> The objective of this study was to determine the prognostic value of positive lymph nodes (LNs) in patients with renal cell carcinoma (RCC) and tumor thrombus (TT) and to explore risk factors predicting LNs metastasis. <b><i>Methods:</i></b> We retrospectively analyzed 216 patients with RCC and TT treated at a single institution from January 2015 to December 2019. Overall survival (OS) and progression-free survival (PFS) was estimated using the Kaplan-Meier curves divided by pathological LN status. Associations between clinicopathological features and survival outcomes were evaluated using Cox regression models. Logistic regression model was performed to determine risk factors associated with LN metastasis. <b><i>Results:</i></b> We identified 216 patients with RCC and TT including 85 (39.4%) who did and 131 (60.6%) who did not undergo lymph node dissection. Pathologically positive LNs were found in 18 (8.3%) cases. pN1 had significant worse OS (median: 21 vs. 41 and 56 months, <i>p</i> &#x3c; 0.001) and PFS (median:14 vs. 29 and 33 months, <i>p</i> &#x3c; 0.001) than pN0 and pNx respectively. However, survival outcomes of OS and PFS were similar between pNx-0/M1 and pN1/M0 group and between 1- and ≥2-node-positive group. Non-CCRCC (<i>p</i> = 0.001), sarcomatoid differentiation (<i>p</i> &#x3c; 0.001), and pathologically positive LNs (<i>p</i> = 0.025) were independent prognostic predictors predicting worse OS while distance metastasis (<i>p</i> = 0.009), non-CCRCC (<i>p</i> = 0.023), necrosis (<i>p</i> = 0.014), sarcomatoid differentiation (<i>p</i> = 0.003), and pathologically positive LNs (<i>p</i> = 0.007) were independent prognostic indicators predicting worse PFS. Clinically positive LNs (<i>p</i> = 0.014) and sarcomatoid differentiation (<i>p</i> = 0.009) were predictors of positive LNs. <b><i>Conclusions:</i></b> LNs metastasis independently associated with worse survival outcomes in RCC and TT populations, with similar survival outcomes compared to distance metastasis. Therefore, more accurate risk stratification is warranted for guiding postoperative surveillance and adjuvant therapy.