Surgical aspects in the treatment of patients with unilateral wilms tumor: a report from the SIOP 93-01/German Society of Pediatric Oncology and Hematology.

Objective: To assess surgical aspects in the treatment of children with unilateral Wilms tumor based on data from the Cooperative Tumor Study SIOP 93-01 of the German Society of Pediatric Hematology and Oncology.

Summary Background Data: Although multiple international study trials exist for the treatment of nephroblastoma, the impact of surgical details and the outcome of the patients have not yet been described comparing different approaches of the trials.

Methods: Treatment results of SIOP 93-01 of the German Society of Pediatric Hematology and Oncology were analyzed regarding frequencies of operations by surgeons and hospitals, surgical approaches, and operating subspecialties. Special attention was given to surgical complications, postoperative tumor stages and event-free survival.

Results: Data sets from 757 of 1020 registered patients were received for evaluation. A unilateral Wilms tumor was observed in 512 of 757 children.Median follow-up was 4.8 years (1.2-10.7). Event-free survival rates were comparable for frequencies of operation by surgeons and hospitals, surgical approaches, and surgical specialties. Intraoperative tumor rupture rates were 12% in primarily operated patients (protocol violations) versus 3.2% inpatients after preoperative chemotherapy. There were 7% intraoperative ruptures for hospitals and surgeons performing 1 operation per year, and 3%when more than 4 operations per year were carried out. Sampling of hilar lymph nodes was often incomplete for all surgical subspecialties.

Conclusion: While the event-free survival for all groups is equal, there may be some long-term complications as a result of the more intensified therapy required for patients who suffer intraoperative ruptures. This will be defined only with longer term studies of late effects of the more intensified therapy. There is,however an increased rate of complications and ruptures associated with the use of midline laparotomy rather than a transverse or thoracoabdominal incision.