Is radiotherapy required in first‐line treatment of stage I diffuse anaplastic Wilms tumor? A report of SIOP‐RTSG, AIEOP, JWiTS, and UKCCSG

Background As a significant proportion of relapses occurred in the tumor bed or abdomen on patients with the fifth National Wilms Tumor Study stage I anaplastic Wilms tumor (WT), flank radiotherapy was added for stage I anaplastic WT in the subsequent study of the Children's Oncology Group (AREN0321). Preliminary results revealed reduction of relapse rate and improved survival. In cases treated with preoperative chemotherapy, such as in...