Bilateral Wilms tumor: 10-year experience from a single center in China.

Background:Nephron sparing surgery (NSS) had become the main surgical treatment for bilateral nephroblastoma. But it remained a challenge for surgeons to balance the dilemma between complete tumor resection to reduce tumor recurrence and renal parenchyma preservation to reduce end-stage renal disease (ESRD). In this study, we summarized our clinical experience for bilateral Wilms tumors managed in our center and evaluated the influence of different surgical approaches on prognosis. Methods:The clinical data of patients with bilateral Wilms tumor in our hospital from January 2010 to December 2020 were retrospectively analyzed, and the clinical symptoms, surgical approaches and prognosis of the disease were summarized. Results:We reviewed medical records of 16 patients, including 13 (81.3%) girls and 3 (18.7%) boys. The mean age of the patients was 17.88±11.65 months (range, 6-42 months). Five patients presented with hypertension and two presented with hemihypertrophy. Fifteen cases had synchronous tumors, while only one patient had metachronous bilateral lesions. Thirteen patients received neoadjuvant chemotherapy and only 8 kidneys (30.8%) responded to chemotherapy. Two patients gave up surgery, and the other fourteen patients underwent radical resection, of which 2 patients only underwent unilateral radical nephrectomy (RN); 7 and 5 patients underwent single-stage and two-stage operation for bilateral lesions, respectively. In all surgical patients, RN was performed on 5 kidneys, and NSS was performed on 21 kidneys. The positive margins after NSS were found in 6 kidneys (35.3%). After a median follow-up period of 26.3 months, local tumor recurrence and renal insufficiency occurred in two and one patients. The 5-year overall and event-free survival rates were 78.1% and 58.6%, respectively. In univariable analysis, the survival rate in the initial chemotherapy group (92.3%) was significantly higher than that in the initial surgery group (33.3%) (P=0.048), whereas positive margin and staged operation (P>0.05) appeared not significantly associated with overall survival. Conclusions:The proportion of tumor reduction after preoperative chemotherapy is relatively low for bilateral Wilms tumor, but preoperative chemotherapy could improve overall survival. NSS is recommended for bilateral Wilms tumor, and the customized procedure can be selected according to the location and anatomical features of tumor.