The National Wilms Tumor Study (NWTS) was established in 1969. The original membership included institutions from Children's Cancer Group, the Pediatric Division of the Southwest Oncology Group (SWOG) and the Pediatric Division of Cancer and Leukemia Group B (CALGB). The pediatric divisions of SWOG and CALGB were subsequently merged to form the Pediatric Oncology Group. In 2001 the National Wilms Tumor Study Group (NWTSG) was merged with the Children's Cancer Group, the Pediatric Oncology Group and the Intergroup Rhabdomyosarcoma Study Group to form a new national organization, the Children's Oncology Group (COG). Patient entry into NWTSG clinical trial protocols was completed in 2002. Future clinical trials for children with renal tumors will be conducted by the renal disease committee of the COG. The "NWTS" designation (no longer a group) is still used for the continuing Late Effects Study of patients who were enrolled in one of the earlier NWTS clinical trials.
The initial goals of the National Wilms Tumor Study were to improve the survival of children with Wilms tumor and other renal tumors, to study the long-term outcome of children treated successfully by identifying adverse effects of treatment, to study the epidemiology and biology of Wilms tumor and to make information regarding successful treatment strategies for Wilms tumor available to physicians around the world.
The therapeutic studies conducted by the National Wilms Tumor Study involved over 250 pediatric oncology treatment centers in the United States, Canada, and several other countries. During its final years, approximately 440 patients with Wilms tumor were entered on the study annually, including an estimated 70-80% of all incident cases in the United States.