Wilms' Tumor: Changing Tole of Radiation Therapy

Wilms' tumor is a highly curable neoplasm. Greater that 90% of all children with this disease can be expected to become long-term survivors. Although radiation therapy (RT) was once the mainstay of nonsurgical treatment, its use has been reduced both in indications and in dosage because of the chemoresponsiveness of the tumor. In the Third National Wilms' Tumor Study (NWTS 3), patients with stage II tumors were shown not to require postoperative RT, and in patients with stage III tumors, 10 Gy was sufficient. In NWTS 5, patients with stage III favorable histology (FH), stage IV FH (with abdominal stage III), and stage II-IV anaplastic and all patients with clear cell sarcoma receive 10 Gy to to the abdomen (usually given as 1.8 Gy x 6-total doe 10.8Gy). Results from the International Society of Paediatric Oncology, in which downstaged patients had a higher incidence of abdominal relapse, and the United Kingdom Children's Cancer Study Group first Wilms' Tumor Study, in which omission of whole-lung RT led to lowered survival in stage IV patients, suggest caution in further modifications of RT at this time.