Surgery only for the treatment of patients with stage I (Cassady) Wilms' tumor.

A prospective pilot study was undertaken to examine the outcome of patients with Stage I (Cassady) Wilms' tumor treated with nephrectomy only. Eight consecutive patients fulfilling the criteria for Stage I (Cassady) Wilms' tumor (age less than 2 years with unilateral, nonmetastatic, favorable histopathologic type, and tumor weight less than 550 g) underwent nephrectomy with no further therapy. All eight patients were alive and free of disease with a mean follow-up period of 5 years. There was one tumor recurrence that involved a metachronously occurring bilateral tumor. Overall survival (100%) and event-free survival (88%) were comparable with clinical trials in which patients received adjuvant therapy. Patients with Stage I (Cassady) Wilms' tumor can be successfully treated with nephrectomy alone, thereby eliminating the toxicity of adjuvant therapy.