We sought to assess if adding a biopsy proven histologic subtype to a model that predicts overall survival that includes variables representing competing risks in observed, biopsy proven, T1a renal cell carcinomas, enhances the model's performance.
The National Cancer Database was assessed (years 2004-2015) for patients with observed T1a renal cell carcinoma who had undergone renal mass biopsy. Kaplan-Meier curves were utilized to estimate overall survival stratified by histologic subtype. We utilized C-index from a Cox proportional hazards model to evaluate the impact of adding histologic subtypes to a model to predict overall survival for each stage.
Of 132 958 T1a renal masses identified, 1614 had biopsy proven histology and were managed non-operatively. Of those, 61% were clear cell, 33% papillary, and 6% chromophobe. Adjusted Kaplan-Meier curves demonstrated a difference in overall survival between histologic subtypes (P = 0.010) with greater median overall survival for patients with chromophobe (85.1 months, hazard rate 0.45, P = 0.005) compared to clear cell (64.8 months, reference group). Adding histology to a model with competing risks alone did not substantially improve model performance (C-index 0.65 vs 0.64 respectively).
Incorporation of histologic subtype into a risk stratification model to determine prognostic overall survival did not improve modeling of overall survival compared with variables representing competing risks in patients with T1a renal cell carcinoma managed with observation. These results suggest that performing renal mass biopsy in order to obtain tumor histology may have limited utility. Future studies should further investigate the overall utility of renal mass biopsy for observed T1a kidney cancers.
International journal of urology : official journal of the Japanese Urological Association. 2022 Apr 26 [Epub ahead of print]
Jamie Michael, Nermarie Velazquez, Audrey Renson, Hung-Jui Tan, Tracy L Rose, Chelsea K Osterman, Matthew Milowsky, Stella K Kang, William C Huang, Marc A Bjurlin
School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA., Division of Urologic Oncology, Department of Urology, NYU Langone Health, New York City, New York, USA., Department of Clinical Research, NYU Langone Hospital - Brooklyn, Brooklyn, New York, USA., Department of Urology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA., Division of Oncology, Department of Medicine, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA., Department of Radiology, NYU Langone Health, New York City, New York, USA.