Abstract
BACKGROUND: Wilms tumor (WT) is the most common pediatric malignancy of the kidney. Past studies describing WT incidence and survival used surveillance data with < 30% of the US population. We evaluated differences in WT incidence and survival comparing demographic groups and tumor characteristics. METHODS: We analyzed new cases of WT among patients aged < 20 years at diagnosis by using incidence data from US Cancer Statistics (USCS) for 2003-2020 and 5-year relative survival (RS) data from the National Program of Cancer Registries (NPCR) for 2001-2019. To assess incidence trends, average annual percent change (AAPC) was calculated by using joinpoint regression. Relative survival (RS) and all-cause survival were calculated overall and by demographic and clinical variables. RESULTS: During 2003-2020, 8218 cases of WT were reported in USCS, which represented an age-adjusted incidence rate of 5.7 cases per million. Rates were the highest among females (6.3), children aged 0-4 years (17.2), and non-Hispanic Black patients (7.1). Overall, trends remained stable (AAPC = -0.4, 95% CI: -1.4 to 0.4). Among 7567 cases of WT in NPCR, 5-year RS was 92.6%. Patients with the lowest survival include the following: those aged 10-19 years (hazard ratio [HR] = 1.65, 95% CI: 1.02-2.65); non-Hispanic Black patients (HR = 1.39, 95% CI: 1.11-1.76); those with regional stage (HR = 1.93, 95% CI: 1.47-2.54) or distant stage (HR = 5.12, 95% CI: 3.99-6.57); and patients from nonmetropolitan counties (HR = 1.46, 95% CI: 1.09-1.96). Individuals diagnosed during 2011-2019 (HR = 0.64, 95% CI: 0.53-0.77) had higher survival than those diagnosed during 2001-2010. CONCLUSIONS: The highest WT incidence rates were patients who were female, 0-4 years, and non-Hispanic Black. Survival improved during the study period; survival differed by race, ethnicity, metropolitan status, and age. Further studies to delineate the causes of these disparities may improve outcomes.