Identification and Management of High Risk Wilms Tumors

Pediatric renal tumors comprise approximately 5% of malignancies in children under 15 years old and 3.6% of malignancies in children under 20 years old (1). Among 9731 patients registered with the National Wilms Tumor Study Group (NWTSG) (1969-2002), Wilms tumor composed the vast majority of childhood renal tumors (92%), followed by clear cell sarcoma of the kidney (3.4%), congenital mesoblastic nephroma (1.7%), malignant rhabdoid tumor (1.6%), and rare miscellaneous neoplasms including primitive neuroectodermal tumor (PNET), synovial sarcoma, neuroblastoma, and cystic nephroma (1.1%). Although not historically included on NWTSG studies, renal cell carcinoma accounts for 8% of renal tumors in children age 0-19 years according to data from the Surveillance, Epidemiology, and End Results (SEER) program (1). The study of Wilms tumor has had significant impact on the field of oncology. Tenets of cancer biology, such as Knudson’s two-hit model, tumor suppressor genes, and alteration of genomic imprinting as a cancer initiator, were pioneered in Wilms tumor. Wilms tumor also provided a paradigm for multidisciplinary treatment approaches and the conduct of cooperative group studies. Through the efforts of the NWTSG, International Society of Pediatric Oncology (SIOP), United Kingdom Children’s Cancer Study Group (UKCCSG) and others, the overall durable survival rate for Wilms tumor now approximates 90%. This remarkable feat has been achieved while reducing radiation and anthracycline exposure in most patients. Despite this success, it is premature to declare victory in the battle against Wilms tumor.