Surgical complications after primary nephrectomy for Wilms' tumor: report from the National Wilms' Tumor Study Group

Surgical complications are a recognized morbidity of the treatment of patients with Wilms tumor. This study examines the incidence of surgical complications in the most recently completed study from the National Wilms' Tumor Study Group (NWTSG).

The fourth National Wilms' Tumor Study (NWTS-4) enrolled 3,335 patients from August 1986 to August 1994. A random sample of 534 patients was selected from 2,290 eligible patients randomized to treatment regimens or enrolled in the followed category and treated according to NWXTSG protocol. The patient records received at the NWTSG Data and Statistical Center were analyzed for surgical complications (intraoperative and postoperative).

Sixty-eight patients (12.7%) experienced 76 complications. Intestinal obstruction was the most common complication (5.1% of patients), followed by extensive hemorrhage (1.9%), wound infection (1.9%), and vascular injury (1.5%). The incidence of surgical complications in NWTS-4 was significantly lower than NWTS-3 (12.7% versus 19.8%, p < 0.001). There has been a marked decrease in the risk of extensive intraoperative bleeding and major intraoperative complications. Factors previously shown to be associated with an increased risk for surgical complications, together with indicators of type of hospital and surgeon specialty, were analyzed by multiple logistic regression analysis. Intravascular extension into the inferior vena cava (IVC), the atrium, or both (p = 0.02; odds ratio [OR] 3.8, 95% confidence interval [CI] 1.2, 11.8), and nephrectomy performed through a flank or paramedian incision (p = 0.02; OR 5.3, 95% CI 1.3, 22) were both associated with increased risk of complications. Tumor diameter greater than or equal to 10cm was also associated with an increased risk of surgical complications (p = 0.05; OR 2.0, 95% CI 1.0, 3.9). The risk of complications was higher if the nephrectomy was performed by a general surgeon (OR 9.0, 95% CI 1.3, 65; p = 0.03) rather than a pediatric surgeon (reference group, OR 1.0) or pediatric urologist (OR 0.7, 95% CI 0.3, 1.8).

The incidence of surgical complications in NWTSG patients undergoing primary nephrectomy has significantly decreased over the past decade. But surgical morbidity should not be overlooked. It is important that surgeons treating young children with solid tumors are aware of their role and the potential risks encountered in removal of the primary tumor. This study found that surgical specialists who primarily treat children can perform these operations with lower surgical morbidity.