Intravascular extension of Wilms tumor

Objective To define the incidence and manifestations of and optimal therapy for child ren with intravascular extension of Wilms tumor. Methods Children on a collaborative study of Wilms tumor who had intravascular exte nsion into the inferior vena cava (IVC) or atrium were identified. Surgical checklists and surgical and pathology reports were reviewed. Results One hundred sixty-five of 2,731 patients had intravascular extension of Wil ms tumor. The level of extension was IVC in 134 and atrium in 31. Sixty-nin e had received preoperative therapy (55 with IVC extension and 14 with atri al extension) for a median of 8 weeks. Complications during preoperative ch emotherapy were seen in five patients (tumor embolism and tumor progression in one each, and three with adult respiratory distress syndrome, one of wh ich was fatal). The intravascular extension of the tumor regressed in 39 of 49 children with comparable pre- and posttherapy radiographic studies, inc luding 7 of 12 in whom the tumor regressed from an atrial location, thus ob viating the need for cardiopulmonary bypass. Surgical complications occurre d in 38.7% of the children in the atrial group and 17.2% in the IVC group. The frequency of surgical complications was 26% in the primary resection gr oup versus 13.2% in children with preoperative therapy. When all the compli cations of therapy were considered, including those that occurred during th e interval of preoperative chemotherapy tone of the five also had a surgica l complication), the incidence of complications among those receiving preop erative therapy was not statistically different from the incidence among th ose who underwent primary resection. The difference in 3-year relapse-free survival (76.9% for 165 patients with intravascular extension, 80.3% for 1, 622 patients with no extension) was not statistically significant whether o r not it was adjusted for stage and histology. Conclusions Preoperative treatment of these children may facilitate resection by decrea sing the extent of the tumor thrombus, but the overall frequency of complic ations is similar in both groups.