Impact of Age on Overall Survival Among Children With Wilms Tumor

Objectives: International trials have reported conflicting findings on whether the association between age and worse overall survival (OS) among children with Wilms tumor (WT) is due to age as an independent prognostic factor or the observation of more advanced disease at older ages. We sought to further elucidate this relationship using a population-based registry analysis. Methods: The Surveillance, Epidemiology, and End Results database was queried for all patients diagnosed with WT under the age of 20. The association between age and OS was assessed using multivariable Cox proportional hazards regression. Results: In this study, 3463 patients (54% female) were diagnosed with WT between 1975 and 2016. More advanced stage, larger primary tumor size, lymph node involvement, disease requiring radiotherapy, and omission of surgery were associated with worse OS (P<0.05). More advanced stage, larger primary tumor size, and disease requiring radiotherapy were also associated with older age, whereas bilateral disease was associated with younger age (P<0.001). On average, each year of age conferred an incremental hazard ratio (HR) of 1.07 (95% CI, 1.01 to 1.12, P=0.018) independent of relevant covariates. The rise in adjusted OS HR was most pronounced after the transitions in diagnosis age from 2 to 3 (HRage 3–15 vs. 0–2 1.77, 95% CI, 1.11 to 2.82, P=0.016) and from 15 to 16 (HRage 16–19 vs. 3–15 2.58, 95% CI, 1.06 to 6.25, P=0.036). Conclusions: Diagnosis of pediatric WT at an older age was found to be independently associated with worse OS. Although additional prospective studies are warranted to examine tumor biology and other potential correlates, more aggressive treatment of older children based on age, especially as they approach early adulthood, may be considered in the multidisciplinary management of WT.