Treatment of Newly Diagnosed Patient's With Wilm's Tumor Requiring Abdominal Radiation Delivered With Proton Beam Irradiation

Participants are being asked to take part in this clinical trial, a type of research study, because the participants have a Wilms Tumor cancer. Primary Objectives To determine whether delivery of proton beam radiation to a conformal reduced target volume in the flank allows normal flank growth compared to the contralateral untreated side and non-irradiated patients. Secondary Objectives To deliver proton beam radiation to a conformal reduced target volume (partial kidney proton beam radiation therapy) in the affected kidney(s) for patients with Stage V (bilateral Wilms tumor) and specific involved surgical margins yielding no reduction in the high control rates seen with more traditional flank / whole kidney fields. Exploratory Objectives * Study the feasibility of sparing the residual kidney, spine and liver in patients requiring whole abdomen radiation therapy using either a proton beam treatment technique or intensity-modulated radiation therapy ( IMRT) photon based technique. * Study the feasibility of delivering whole lung radiation therapy with proton beams with the goals of sparing the developing breast tissue, heart structures, thyroid and liver. * Develop simultaneous xenografts and organoid models from the same starting material to study Wilms tumor biology and compare responses to chemotherapeutic agents. * Define the evolution of organ specific (kidney, liver, pancreas, etc.) abnormalities (laboratory studies) as an early marker of possible late end organ damage and their relationship to radiation. * Study and evaluate impact of proton therapy on the musculoskeletal system and physical performance and compare with photon therapy cases treated with classical treatment fields. * Assess CTC-AE and Pediatric Patient Reported Outcomes during radiation and in follow-up, correlating with disease, treatment and patient variables. * Correlate quantitative MRI values, including apparent diffusion coefficient (ADC) values, with histopathology findings post-surgery in children with (bilateral) Wilms. * Assess daily variations in proton range along each treatment beam using standard pre-treatment cone beam CT or on-treatment MR.

Participants will receive proton beam radiation therapy (PBRT) according to stage and surgical findings. Favorable Histology Stage I \& II and FH Stage III/IV Delayed Local Control with clear surgical margins and pathologically negative lymph nodes: Participants will undergo complete surgical resection at diagnosis or after 6-12 weeks of induction chemotherapy. PBRT will not be administered to the primary site in those with no evidence of spill, peritoneal involvement, lymph node (LN) involvement or microscopic residual in the abdomen. Systemic therapy will be delivered in a standard of care manner according to histology and stage. Stage III \& IV Adjuvant RT: Participants will undergo surgical resection at diagnosis or after 6-12 weeks of induction chemotherapy. Those with evidence of LN involvement, surgical margin involvement, local or diffuse spill, gross disease in the renal bed or peritoneal implants, will receive adjuvant PBRT. Systemic therapy will be delivered in a standard of care manner according to histology and stage. Stage V Adjuvant RT: Participants will undergo partial nephrectomy after 6-12 weeks of induction chemotherapy. Those with evidence of LN involvement, surgical margin involvement, local or diffuse spill, gross disease in the renal bed or peritoneal implants, will receive adjuvant PBRT. Systemic therapy will be delivered in a standard of care manner according to histology and stage. Systemic therapy will follow a well-defined standard of care based on Children's Oncology Group (COG) approaches including pre-operative chemotherapy and adjuvant chemotherapy. The intent will be to standardize chemotherapy to ensure a consistent background of standard of care therapy, while not mandating additional data collection beyond the specific trial objectives.