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.