Survival outcomes of sarcomatoid renal cell cancer (sRCC) compared to clear cell renal cell cancer (ccRCC): An analysis of SEER data.
Journal of Clinical Oncology
Background: Renal cell carcinoma (RCC) with sarcomatoid differentiation is a highly aggressive form of RCC. The presence of even a small component of sRCC was shown to independently predict poor survival compared to RCC without sarcomatoid features. We studied the epidemiology and survival outcome of sRCC compared to ccRCC by reviewing the SEER data. Methods: Patients (pts) with histologically confirmed sRCC and ccRCC between 2012-2015 were reviewed in SEER database. Variables included age, gender, ethnicity, histologic grade, stage at diagnosis, and nephrectomy. Primary outcome was 5 year Disease Specific Survival (DSS). Data was analyzed using Kaplan Meier curves and Cox proportional hazards model. Results: A total of 31, 293 pts with RCC were identified in SEER database between 2012 to 2015. 611 pts had sRCC while 30, 682 had ccRCC. The two groups had almost similar demographic features, including mean age (63 ±12 for sRCC vs 61±12 years for ccRCC), male: female ratio (vs 2.3:1 vs 1.7:1) and Caucasian ethnicity (82% vs 85%). More than half of sRCC patients (62%) were metastatic at diagnosis compared to only 11% of ccRCC, which presented most commonly as stage I disease (63%). The histologic grade was higher in sRCC patients (43% grade 4 vs 45% grade 2 in ccRCC subjects). Nephrectomy rates were almost similar for stages I-III in the two groups (94% in sRCC vs 93% in ccRCC) while lower in stage IV sRCC (44% vs 54%). Across all stages and at every time point, sRCC was associated with increased mortality in the univariate analysis. In the multivariate regression analysis (table), advanced stage was the strongest independent predictor of mortality (HR 11.9), followed by high histologic grade (HR 3.6) and sarcomatoid histology (HR 2.9). Nephrectomy was protective (HR 0.3). Age was associated with worse outcomes (HR 1.016 per unit change). Conclusions: sRCC are more aggressive and tend to present as metastatic disease. sRCC has worse outcomes across all stages compared to ccRCC even after adjusting for potential confounders. Advanced stage and histologic grade remain the two strongest predictors of disease-specific mortality, sarcomatoid histology demonstrated a significant impact on outcome.
Gupta, R. , Ionescu, F. , Jindal, V. , Khoury, J. , Anusim, N. I. & Jaiyesimi, I. A. (2020). Journal of Clinical Oncology, 38 (15), e17101. doi: 10.1200/JCO.2020.38.15_suppl.e17101.