The Impact of Older Age at Diagnosis on Wilms Tumor Characteristics and Patient Outcomes: A Children's Oncology Group Study.

Abstract

Background: Although Wilms tumor (WT) is the most common kidney cancer of childhood, it also presents infrequently in adolescents and even adults. Older patients with WT have inferior survival, but the reasons for this are unclear, and age is not currently used for therapeutic risk stratification. This study evaluates age as a prognostic variable and examines the influence of clinical and biological features on outcomes in a cohort of older patients with WT.

Patients and methods: We evaluated 4,100 patients with unilateral WT on Children's Oncology Group protocol AREN03B2. "Standard-age" patients (age 0-9 years) were compared with those presenting at "older-age" (age 10-30 years). The impact of age on survival was evaluated across the entire cohort and stratified by stage and histology.

Results: There were 3,936 standard-age and 164 older-age patients. Older-age patients were more likely to have higher local (P=.009) and overall disease stage (P<.001), larger tumor diameter (P<.001), longer intervals between diagnostic imaging and renal surgery (P<.001), no lymph nodes sampled (P<.001), and treatment that included radiation (P=.010). No older-age patients had WT predisposition syndromes. The effect of age as a continuous variable was significantly associated with worse prognosis for event-free and overall survival after accounting for differences in disease stage and histology. There was neither higher rates of anaplasia nor high-risk tumor cytogenetics in older-age patients to account for this survival disadvantage.

Conclusions: Advancing age is an inferior continuous prognostic risk factor in patients with unilateral WT, independent of conventional risk stratification parameters of stage and histology. Future studies should prospectively interrogate the biology of older-age patients and incorporate advanced age into therapeutic risk stratification.