The impact of lymph node dissection and positive lymph nodes on cancer-specific mortality in contemporary pT_2-3 non-metastatic renal cell carcinoma treated with radical nephrectomy.

Abstract

To assess the effect of lymph node dissection (LND), number of removed nodes (NRN), and number of positive nodes (NPN), on cancer-specific mortality (CSM) in contemporary vs historical patients with pT_2-3 N_any M₀ renal cell carcinoma (RCC) treated with radical nephrectomy (RN). Within the Surveillance, Epidemiology, and End Results database (2001-2013), we identified patients with non-metastatic pT_2-3 N_any RCC who underwent RN with or without LND. Kaplan-Meier analyses and multivariable Cox regression models with propensity score weighting for inverse probability of treatment were used. Of 25 357 patients, 24.8% underwent LND (2001-2007: 3 167 patients vs 2008-2013: 3 133 patients). The median NRN was 3 (interquartile range [IQR]: 1-7). Positive nodes were identified in 17.1%: 9.3% of pT₂ and 21.6% of pT₃ patients, who underwent LND. The median NPN was 2 (IQR: 1-3). In multivariable models, LND did not decrease CSM (hazard ratio [HR] 1.29; P < 0.001). LND extent, defined as NRN, did not decrease CSM (HR 0.94; P = 0.3). Finally, multivariable models testing the effect of NPN showed increased CSM in pT₃ but not in pT₂ patients (HR 1.29 and 1.58, P = 0.02 and P = 0.1, respectively). NRN exerted a protective effect on CSM in patients with positive nodes (HR 0.98; P = 0.007). In contemporary and historical patients LND or its extent do not protect from CSM. However, the NPN increases the rate of CSM in pT₃ patients. Consequently, LND and its extent appear to have little if any therapeutic value in pT_2-3 N_any M₀ patients, besides its prognostic impact. High-risk non-metastatic patients may represent a target population for a multi-institutional prospective trial.