Intraoperative radiation therapy for Wilms' tumor in situ or ex vivo.

Patients with bilateral Wilms' tumor who have local recurrence after undergoing maximum-dose multitechnique therapy are problematic. The role of surgery in the management of these patients is changing from ablation to preservation of renal tissue. Bilateral nephrectomy is reserved as a last resort. Intraoperative radiation therapy (IORT) is advantageous to conservative management, as illustrated by the current cases of two children with recurrent Wilms' tumors in their remaining kidneys. Both children underwent limited surgery and precisely directed IORT. In one patient the nephron-sparing surgery and IORT were performed in situ. In the other the kidney was removed, treated with ex vivo bench surgery and radiation surgery, and then reimplanted. The adjuvant use of IORT, either in situ or ex vivo, in nephron-sparing surgery permits complete obliteration of gross and microscopic disease while maximizing residual renal function.