Comparison of patients with high-risk nonmetastatic clear cell renal carcinoma in adjuvant therapy trials versus nonclinical trial patients.

361 Background: Characteristics of patients with high risk for recurrence non-metastatic renal cell carcinoma (nmRCC) participating in adjuvant therapy clinical trials post-nephrectomy have not been well described. We evaluated high risk nmRCC patients in the CKCis database to explore differences between trial and non-trial patients. Methods: Adult patients undergoing partial or radical nephrectomy for clear cell nmRCC between January 1, 2011 and March 31, 2021 were included. CKCis is a prospective cohort of patients from 14 Canadian academic institutions. Patients with high risk nmRCC (using modified UCLA Integrated Staging System) were included. Demographic, clinical, and survival statistics were analyzed for all patients and comparatively for the trial and non-trial groups. Results: 1459 patients, including 63 in adjuvant trials, were evaluated. 71% were male, 91% had pT3N0M0 disease. Disease characteristics including tumor size, stage, grade, location, necrosis, and margin status were similar between groups. Trial patients were younger (mean age 58.1 vs. 63.6; p < 0.0001) and had lower Charlson Comorbidity Index scores (median 4 [3,6) vs. 5 [4,6] p < 0.001). Estimated overall survival (OS) at 5 years was 80.8% (95% CI, 65,90) for trial patients and 74.8% (95% CI, 71,78.2) for non-trial patients. Recurrence-free survival at 5 years for trial patients was 48.6% (95% CI, 34,61.7) and 39.2% (95% CI, 35.2,43.1) for non-trial patients. Conclusions: Patients in adjuvant trials were younger and healthier at baseline than the average high risk nmRCC CKCis patient. Trial patients appear to have had longer time to recurrence and longer survival compared to non-trial patients, although not reaching statistical significance. Selection bias is common in clinical trials and evaluation of real-world population-based evidence of patients receiving adjuvant therapy will be important to ensure phase 3 trial results have external validity.