Long-term outcome of nephron sparing surgery and simple nephrectomy for unilateral localized Wilms tumor

PURPOSE: We retrospectively assessed survival and local recurrence rates in children with unilateral localized Wilms tumor (WT) treated with nephron sparing surgery (NSS) or simple nephrectomy with removal only of the perirenal fat adherent to the tumor surface. MATERIALS AND METHODS: The records of 70 children with renal tumor, operated on by the same surgeon between January 1968 and December 2003, were reviewed. Of 64 children with WT 52 with localized nonanaplastic WT were enrolled. Treatment was administered according to International Society of Pediatric Oncology protocols 1 to 2001 in all patients but 7, who were operated on between 1968 and 1971. Patients were stratified as having stage I (27), stage II (23) or stage III (2) disease. Surgical treatment included 40 simple nephrectomies, 10 NSSs (only stage I cases ascertained by frozen section) and 2 radical nephrectomies. Mean patient age at operation was 39.5 months (range 1 to 126). Followup ranged from 27 to 431 months (mean 188.4). RESULTS: Event-free survival rate in all localized stages was 88.5% (stage I 92.6%, stage II 87%, stage III 50%). Two infants with stage I disease died after surgery for reasons not related to malignancy. Only 1 patient with stage II lymph node negative WT had local relapse. CONCLUSIONS: Our results are similar to those achieved by radical nephrectomy in previous studies. Leaving Gerota's fascia in situ does not seem to confer a higher risk of local recurrence in patients with low stage nonanaplastic WT. After NSS Gerota's fascia may be used to cover the defect and to maintain tissue plains, thus, facilitating reintervention if necessary.