INTRODUCTION AND OBJECTIVES: Nephron-sparing surgery (NSS) for bilateral Wilms tumor (BWT) has enabled preservation of renal parenchyma, delayed or avoided renal replacement therapy, and improved quality of life. However, to date only short-term follow-up has been published. We describe our intermediate-term outcomes in patients after NSS for BWT.

METHODS: All patients who underwent NSS for BWT at our institution between November 1999 and February 2009 were identified. Data were abstracted on patient demographics, tumor characteristics, surgical technique, pre- and postoperative renal function and blood pressure, and need for medical and/or surgical therapy for renal disease.

RESULTS: 23 patients (12 males, 11 females, mean age at surgery 2.3 years) were identified, all of whom were followed for at least 5 months postoperatively. 19 patients had favorable histology, 2 had focal anaplasia, and 2 had diffuse anaplasia. Three patients underwent unilateral nephrectomy and contralateral NSS, while 20 underwent bilateral NSS. All patients received neoadjuvant chemotherapy and 8 (34.8%) patients received adjuvant flank radiation (XRT; 5 positive margins, 2 focal anaplasia, 1 vena caval involvement). At a mean follow-up of 37.7 months (range 5.2-104.3), eight (34.8%) patients are hypertensive (blood pressure >95th percentile for height by age); 5 (62.5%) of these patients require antihypertensive medication. Mean change in creatinine from preoperative levels was 0.08 mg/dL (range 0-0.4). Four of 10 patients (40%) with urinalyses had proteinuria (3 mild, 1 moderate). 3 of 4 patients who have undergone functional renal studies have glomerular filtration rates (GFR) below normal; in these patients, mean GFR was 57.8 cc/min (range 33-99). One patient developed transient acute renal failure owing to recurrent obstructing intracalyceal tumor; this resolved after tumor resection. One patient required completion native nephrectomy and renal transplantation for renal failure. 2 patients have died, one of progressive disease and the other from a brain tumor.

CONCLUSIONS: NSS remains a feasible treatment option for patients with BWT, with a minority of patients experiencing significant deterioration of renal function in the first several years. Hypertension is more common and typically can be controlled with oral medication. Blood pressure and renal function should be followed closely in patients following NSS. Further research aims to evaluate long-term effects of NSS for BWT, as well as to evaluate the individual contributions of chemotherapy, XRT, and NSS to changes in long-term renal function.

Source of Funding: None.