SUO 2017: Sarcomatoid Differentiation in Renal Cell Carcinoma: Does Stage Make A Meaningful Difference On Survival?

Washington, DC ( Sarcomatoid differentiation is present in approximately 4% of patients with renal cell carcinoma (RCC) and is associated with poor clinical outcomes. Dr. Blum and colleagues presented their institutional analysis assessing the impact of stage on survival for this aggressive RCC histology. The objective of this study was to evaluate the impact of sarcomatoid differentiation, especially for patients with lower stage pT1-2 disease. 

The authors queried the Memorial Sloan Kettering Cancer Center kidney cancer database of 3,850 patients with RCC who underwent partial or radical nephrectomy from 2000-2017. Patients were divided into four groups for the analysis: pT1-2NxMx RCC without sarcomatoid features, pT1-2NxMx sarcomatoid RCC, pT3-4 sarcomatoid RCC, and pT3-4 RCC without sarcomatoid features. Clinicopathological outcomes including age, sex, race, primary histology, lymph node involvement and margin status were compared between groups using student t and Chi-squared tests. Overall survival rates were analyzed by constructing Kaplan-Meier curves, p-values were calculated using log-rank tests and fitting Cox proportional hazards models for adjusted analyses. Among these 3,850 cases, 168 (4.4%) sarcomatoid RCC patients were identified of which 33 (19.6%) were pT1-2. The mean overall follow-up time was 59.9 months. When comparing cancer specific survival between groups, survival was poorer in patients with sarcomatoid features regardless of pT stage (p<0.0001). Of note, cancer specific survival was worse in sarcomatoid RCC pT1-2 patients than in non-sarcomatoid pT3-4 patients. Overall survival results were similar, with sarcomatoid tumors having worse estimates on survival analysis (p<0.0001).

In summary, patients with pT1-2 sarcomatoid RCC demonstrated worse cancer-specific outcomes when compared to pT3-T4 RCC without sarcomatoid features, regardless of primary histology. Sarcomatoid differentiation in low-stage disease may be a marker of poor oncologic outcomes requiring more vigilant surveillance and possible inclusion in adjuvant therapy trials. Future directions include combining the current data with other institutions in order to develop a larger cohort of sarcomatoid RCC patients.

Presented by: Kyle A. Blum MD, MSc¹

Co-Authors: Eden Axler ², Renzo G. DiNatale MD¹, Alejandro Sanchez MD¹, Nirmal T. John MD¹, Mazyar Ghanaat MD¹, Mahyar Kashan BSc¹, Maria Becerra MD¹, Paul Russo MD¹, Jonathan A. Coleman MD¹, Satish K. Tickoo MD¹ and A. Ari Hakimi MD¹

Affiliation: ¹Memorial Sloan Kettering Cancer Center, New York, NY; ²University of Michigan, Ann Arbor, MI

Written by: Zachary Klaassen, MD, Society of Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre @zklaassen_md at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC