Researchers evaluated the predictive accuracy of the new AUA risk stratification system for progression-free survival (PFS) and cancer-specific survival (CSS) in patients with clear cell or papillary renal cell carcinoma (RCC) after surgery for localized kidney cancer, and observed that the AUA risk groupings had robust c-indexes for both outcomes. Dr. Andrew Zganjar, MD, from the Department of Urology at the Mayo Clinic in Rochester, Minnesota, presented the findings at the 22nd Annual Meeting of the Society of Urologic Oncology
Additionally, the study compared the AUA system to the published Mayo risk model. “The 2018 Mayo model performed better than the AUA risk stratification system for PFS and CSS in patients with clear cell RCC whereas the AUA risk group was better for papillary RCC,” reported Dr. Zganjar.
The researchers examined 3,191 patients with clear cell RCC and 633 patients with papillary RCC treated with radical or partial nephrectomy from the Mayo Clinic Nephrectomy Registry. Researchers defined disease progression as local ipsilateral recurrence, regional lymph node involvement, distant metastases, or death from RCC. Both the AUA risk groups and the Mayo models were evaluated using c-indexes from Cox proportional hazards regression models.
For patients with clear cell RCC, c-indexes for progression were 0.780 for the AUA groups and 0.815 for the Mayo model (p < 0.001). C-indexes for death from RCC were 0.811 and 0.857, for AUA and Mayo, respectively (p < 0.001). Regarding papillary RCC, the AUA risk groups and the Mayo model had respective c-indexes of 0.775 and 0.751 (p = 0.002) for progression, and 0.830 and 0.803 (p = 0.2) for death from RCC.
Despite the robust accuracy of the AUA risk groupings, the authors noted that the system is considerably limited in that it does not apply to chromophobe RCC, as the WHO/ISUP grading used by the AUA models does not currently grade chromophobe RCC.