title: Experience with retroperitoneal partial nephrectomy in bilateral Wilms tumor.
abstract: BACKGROUND
  Retroperitoneal partial nephrectomy has not been studied as a surgical approach for children with bilateral Wilms tumor. There are advantages to this technique, including isolation of urine leaks to the retroperitoneum, decreased risk of bowel injury, and decreased time to resuming a diet. Presently, all bilateral Wilms tumors are treated with neoadjuvant chemotherapy and attempted nephron-sparing surgery. In this study, we compare the outcomes of the retroperitoneal and transabdominal approaches in doing partial nephrectomy for bilateral Wilms tumor.
  
  
  METHODS
  With the institutional review board approval, we reviewed records of 14 pediatric patients with metachronous or synchronous bilateral Wilms tumors who underwent surgery after chemotherapy between 1994 and 2014. Only operative procedures with the intent to cure were included (n=15) and of these, 5 procedures were retroperitoneal and 10 were transabdominal in approach. Individual kidneys operated upon (n=26) were analyzed using the preoperative radius exophytic/endophytic nearness anterior/posterior location nephrometry score to ensure that resected tumors were comparable between the two surgical groups. Charts were retrospectively analyzed for intraoperative parameters and postoperative course. Differences between parameters were evaluated using Mann-Whitney and chi-square tests.
  
  
  RESULTS
  Resected tumors in both surgical treatment groups had comparable sizes, nephrometry scores, and rates of anaplasia. Operative time, blood loss, and transfusion requirement were similar between the two groups. The extent of lymph node sampling and rates of R0 resection were equivalent. One adverse intraoperative event, a bowel enterotomy, was seen in the transabdominal group. Patients after retroperitoneal partial nephrectomy required half the time to return to an oral diet as compared with those after a transabdominal surgery, approaching statistical significance (p=0.08). Rates of the postoperative urine leak were similar, though two in the transabdominal group required reoperation for drainage. There were four recurrences, all in the transabdominal group.
  
  
  CONCLUSIONS
  Our experience demonstrates that the retroperitoneal approach is equivalent to the transabdominal technique with regards to intraoperative complications, lymph node dissection, and R0 resection. Advantages include less time to resumption of oral feeding, decreased risk of bowel injury, and isolation of urine leaks to the retroperitoneum. It should be considered a viable surgical option in the treatment of bilateral Wilms tumors.
authors.affiliation: Division of Pediatric Surgical Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Irene Isabel P
authors.initials: II
authors.lastname: Lim
authors.affiliation: Division of Pediatric Surgical Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Honeyman
authors.affiliation: Division of Pediatric Surgical Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Fialkowski
authors.affiliation: Division of Pediatric Surgical Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Murphy
authors.affiliation: Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Anita P
authors.initials: AP
authors.lastname: Price
authors.affiliation: Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Abramson
authors.affiliation: Division of Pediatric Surgical Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Michael P La
authors.initials: MP
authors.lastname: Quaglia
authors.affiliation: Division of Pediatric Surgical Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, United States.
authors.forename: Todd E
authors.initials: TE
authors.lastname: Heaton
mesh_terms: D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007680:Kidney Neoplasms / Q000601:surgery*; D008197:Lymph Node Excision; D008297:Male; D009392:Nephrectomy / Q000379:methods*; D012187:Retroperitoneal Space; D012189:Retrospective Studies; D016896:Treatment Outcome; D009396:Wilms Tumor / Q000601:surgery*