['To examine the cancer-specific survival of patients treated with nephrectomy and compared it to that of patients managed without surgery.', 'Of 43,143 patients with renal cell carcinoma (RCC) identified in the 1988-2004 Surveillance, Epidemiology and End Results database, 7068 had locally advanced RCC and with no distant metastasis. These patients had a nephrectomy (6786, 96.0%) or no surgical therapy (282, 4.0%). Multivariable Cox regression models, and matched and unmatched Kaplan-Meier survival analyses, were used to compare the effect of nephrectomy vs non-surgical therapy on cancer-specific survival. Also, competing-risks regression models adjusted for the effect of other-cause mortality. Covariates and matching variables consisted of age, gender, tumour size and year of diagnosis.', 'The 1-, 2-, 5- and 10-year cancer-specific survival of patients who had nephrectomy was 88.9%, 88.1%, 68.6% and 57.5%, vs 44.8%, 30.6%, 14.5% and 10.6% for non-surgical therapy. In multivariable analyses, relative to nephrectomy, non-surgical therapy was associated with a 5.8-fold higher rate of cancer-specific mortality (P < 0.001). Non-surgical therapy was also associated with a 5.1-fold higher rate of cancer-specific mortality in matched analyses (P < 0.001). Finally, competing-risks regression confirmed the statistical significance of the variable defining treatment type (nephrectomy vs non-surgical therapy) in multivariable and matched analyses (P < 0.001).'] Does nephrectomy improve the survival of patients with locally advanced renal cell carcinoma?