[Resection of nephroblastoma: problems and complications--evaluation of the Nephroblastoma Study SIOP 9/GPOH].

The german SIOP 9/GPOH trial and study registered 486 patients with Wilms' tumor (1/89-3/94). Preoperative chemotherapy was the general approach. The indication for primary surgery was limited (age < 0.5 and > 16 years, uncertainty of diagnosis, emergency). Wilms' tumors were operated in 482 patients (4 died preoperatively) in 78 centres. Surgical and histological reports were analyzed concerning intra- and perioperative problems and complications. A total of 60% of pretreated and 39.8% of untreated tumors had local stage I. Nephroblastomas ruptured intraoperatively in 6.0% after pretreatment versus 11.5% in primary surgery. A tumor thrombus in the inferior vena cava complicated surgery in 3.1% of cases. A total of 14.3% of all histologically positive lymphnodes were correctly biopsied by the surgeon despite their normal macroscopic aspect. The overall rate of intra- and perioperative complications was low.