Patterns of Care and Survival Comparison of Adult and Pediatric Wilms Tumor in the United States: A Study of the National Cancer Database
Alonso Carrasco, Jr., MD1, Arya Amini, MD2, Carrye R. Cost, MD1, Brian S. Greffe, MD1, Timothy P. Garrington, MD1, Jennifer L. Bruny, MD1, Arthur K. Liu, MD/PhD2, Nicholas G. Cost, MD1.
1Children's Hospital of Colorado, Aurora, CO, USA, 2University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
BACKGROUND: Wilms tumor (WT) is the most common renal malignancy in children. However, the incidence in adults is rare, with only 0.2 cases per million per year. Previous reports on adult WT have differed in terms of the impact of age on treatment and outcomes. The purpose of this study was to compare national trends in WT treatment management and outcomes by age group.
METHODS: The National Cancer Data Base (NCDB) was queried for patients with WT diagnosed between 2004 and 2013. Patients were grouped by age: pediatrics (35 years. The selected age cutoff of 16 years was used in prior studies on the same topic. Overall survival (OS) was determined using the Kaplan-Meier method. Univariate (UVA) and multivariate (MVA) analyses were performed using Cox proportional hazards regression models. Binary multiple logistic regression identified differences in variables by age category.
RESULTS: In total 3,083 patients were evaluated; the majority were pediatric (n=2,855), followed by adults (n=129), and young adults (n=99). Unadjusted 5-year OS was significant better for pediatrics vs. young adults or adults (91.9%, 78.3%, 53.3% respectively; p<0.001), as was 10-year OS (90.4%, 52.3%, 38.8%; p<0.001) - Figure 1.
On MVA, despite a similar disease stage distribution, OS was significantly better for pediatrics (reference) vs. young adults (hazard ratio [HR], 2.97; 95% confidence interval [CI], 1.90-4.64; p<0.001) and adults (HR, 4.19; 95% CI, 2.57-6.83; p<0.001). In addition to age, other variables associated with worse OS included unfavorable histology (HR, 4.10; p<0.001), bilateral disease (HR, 2.15; p<0.001), stage IV disease (HR, 3.57; p=0.002), and positive lymph nodes on dissection (HR, 2.41-4.19; p<0.001).
When accounting for patient demographics, patients over 16 years of age more commonly presented with unfavorable histology (odds ratio [OR], 5.86; p<0.001) and positive lymph nodes (OR, 1.78; p=0.049), and were less likely to undergo routine lymph node sampling/dissection (OR, 0.13; p<0.001), radiation therapy (OR, 0.34; p<0.001), or chemotherapy (OR, 0.17; p<0.001).
CONCLUSIONS: Within this administrative dataset, adults with WT suffered worse outcomes when compared to children with WT. The survival decrement in adults may be due to higher rates of unfavorable histology and less aggressive treatment including under-utilization of appropriate lymph node sampling, chemotherapy, and adjuvant radiation therapy. 
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