Sarcomatoid Renal Cell Carcinoma: Population-Based Study of 879 Patients

Background: Sarcomatoid renal cell carcinoma (sRCC) constitutes a rare and aggressive subtype of renal cell carcinoma. We aimed to investigate its clinicopathologic characteristics and outcomes at a national level. Patients and Methods: We accessed the National Cancer Institute's Surveillance, Epidemiology, and End Results database (2010-2015) and extracted data on patients with sRCC. We estimated median, 1-, 3-, and 5-year disease-specific survival (DSS) probabilities after generation of Kaplan-Meier curves and used multivariable regression to evaluate variables associated with nephrectomy and DSS. Results: A total of 879 patients with sRCC were identified; 60.9% patients had stage IV disease at diagnosis, and the median tumor size was 8.3 cm (interquartile range, 5.5-12 cm). The 5-year DSS were 77.7%, 67.8%, 35.4%, and 3.5% for patients with stage I, II, III, and IV disease at diagnosis, respectively; median DSS was 9 months (interquartile range, 4-42 months) for the entire cohort. Older age (hazard ratio [HR] = 1.01; 95% confidence interval [CI], 1.00-1.02), higher tumor stage (stage III vs. I: HR = 3.81; 95% CI, 2.18-6.67; stage IV vs. I: HR = 9.89; 95% CI, 5.80-16.98), and performance of nephrectomy (HR = 0.53; 95% CI, 0.43-0.66) were found to independently affect DSS. Conclusion: In the largest sRCC cohort to date, we found that most patients present with metastatic disease, and the prognosis for this disease remains extremely poor. Nephrectomy should be considered in all patients with acceptable surgical risk, including cytoreductive nephrectomy in carefully selected patients with metastatic disease.