The impact of lymph node dissection and positive lymph nodes on cancer-specific mortality in contemporary pT2-3 non-metastatic renal cell carcinoma treated with radical nephrectomy

Objective 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)M(0) renal cell carcinoma (RCC) treated with radical nephrectomy (RN). Patients and Methods 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. Results 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 pT(2) and 21.6% of pT(3) 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 pT(3) but not in pT(2) 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). Conclusion In contemporary and historical patients LND or its extent do not protect from CSM. However, the NPN increases the rate of CSM in pT(3) patients. Consequently, LND and its extent appear to have little if any therapeutic value in pT(2-3)N(any)M(0) patients, besides its prognostic impact. High-risk non-metastatic patients may represent a target population for a multi-institutional prospective trial.