Session: PD08: Kidney Cancer: Epidemiology & Evaluation/Staging/Surveillance I
PD08-07: Predictive Factors for Recurrence and Outcomes in T1a Renal Cell Carcinoma: Analysis of the INMARC (International Marker Consortium for Renal Cancer) Database
Introduction: Stage migration in renal cell carcinoma (RCC) has led to an increasing proportion of diagnoses at earlier clinical tumor stage. While thought of as being low risk, emerging knowledge about heterogeneity of RCC histologies and consequent impact on prognosis led us to further explore outcomes and predictive factors in T1a RCC patients treated with surgical resection. Methods: The INMARC database was queried for patients with T1aN0M0 RCC (= 4 cm) who underwent surgery via partial or radical nephrectomy. Patients were stratified into two groups based on having recurrence (distant or loco-regional) or not. Primary outcome was overall survival (OS). Multivariate analyses (MVA) were performed to analyze clinicopathological variables associated with recurrence and identify predictors of recurrence, cancer-specific mortality (CSM), and all-cause mortality (ACM). Kaplan-Meier analyses (KMA) were conducted for survival assessment between histology types clear cell, chromophobe, papillary, and variant. Results: We analyzed 1,878 patients (median follow up 53.6 months); 101 (5.4%) developed recurrence (median time to recurrence 19.3 months); 51.1% developed distant recurrence, 35.6% had loco-regional recurrence, and 13.9% experienced distant and loco-regional recurrence. MVA demonstrated age (HR=1.02, p=0.02), sex (HR=1.71, p=0.045), diabetes (HR=1.94, p=0.006), high/unclassified grade (HR=2.82-4.40, p<0.001-0.007), papillary (HR=0.37, p=0.013) and variant (HR=2.51, p=0.019) RCC as predictive factors for recurrence. MVA identified high/unclassified grade (HR=3.17-6.22, p=0.002-0.003) and papillary RCC (HR=0.12, p=0.036) as predictive factors for CSM. MVA for ACM demonstrated age (HR=1.03, p<0.001), non-Caucasian race (HR=0.85, p<0.001), high grade (HR=1.42, p=0.024), recurrence (HR=1.86, p=0.003), and GFR <45 (HR=2.89, p<0.001) to be independent risk factors. KMA comparing clear cell, papillary, chromophobe and variant RCC revealed significant differences for 5-year CSS (97.8% vs. 99.3% vs. 98.5% vs. 87.0%, p=0.018) and 5-year RFS (92.4% vs. 96.0% vs. 97.8% vs. 81.7%, p<0.001), but not 5-year OS (89.4% vs. 85.2% vs. 93.2% vs. 73.7%, p=0.34). Conclusions: We noted differential outcomes in T1a RCC based on histology and grade for recurrence and CSM, while renal functional decline in addition to pathological factors and recurrence were predictive for ACM. These findings suggest consideration to refine management and post treatment surveillance strategies in T1a RCC. SOURCE OF Funding: Stephen Weissman Kidney Cancer Research Fund
