Evaluation of the nephron‐sparing surgery formula in Wilms tumors

Abstract

Aim: Definitions of nephron-sparing surgery (NSS) procedures in Wilms tumor (WT) are not clear. The new UMBRELLA protocol offers a formula (NSS(X)-SRM(n)-PRM(n)-RRP(n%)) to better define the different NSS parameters. We aimed to assess the advantages and limits of this new formula. Methods: This retrospective monocentric study included patients operated by NSS for WT from 1975 to 2018. We reviewed the medical records and applied the NSS formula to all included patients. Results: Eighty kidneys were operated on 56 patients at a mean age of 19.2 months (4 days-7.5 years), with 49 partial nephrectomies and 31 tumorectomies. The assessment of the surgical resection margins (SRM) showed a doubt in six cases and one tumor breach. An intact pseudocapsule along the resection margin with no renal parenchyma was found in four cases at pathological resection margins (PRM) assessment, whereas a tumor breach was described in seven cases. Among the six patients with a surgical doubt, only one had a pathological stage III. There were no surgical doubts in the seven patients with tumor breach at pathology. At a mean follow-up of eight years (15 days-28.6 years), eight patients had elevated blood pressure levels. Ten had proteinuria. These two parameters were significantly increased in patients with a remaining renal parenchyma (RRP) of less than half of the initial total renal parenchyma. The serum creatinine level was normal for all except two patients. Conclusion: The new NSS formula described all the crucial elements of NSS. RRP seemed essential for the evaluation of long-term renal function.

Nephron-sparing surgery in nonsyndromic unilateral wilms' tumor: An insight into the ongoing surgical controversy

“…[ 36 ] A new classification system for NSS was also suggested in the Umbrella protocol to optimize the comparison of patient outcomes [ Table 2 ]. [ 37 ] Umbrella protocol differentiates the two popular techniques of NSS into NSS A (PN) and NSS B (enucleation) [ Figure 1 ][ 38 ] and suggests to go for NSS A. It was further emphasized that minimally invasive or laparoscopic surgery should not be done in patients in whom NSS can be safely performed.…”

“…(b) Enucleation (tumorectomy): NSS B (Reproduced from Mrad et al . 2020[ 38 ] with permission from Wiley)…”

Nephron Sparing Surgery in Bilateral Wilms Tumors With Botryoid Growth Pattern

“…On the other side, NSS was realized in 2 patients, and a total nephrectomy was performed in patient 3. The remaining renal parenchyma assessed according to our recent publication3 represented 73/200%, 83/200%, and 50/200%, respectively, in patients 1, 2, and 3 (Fig. 3).…”

Nephron-sparing surgery for Wilms tumor

“…SIOP has developed a standardized NSS "formula" that includes documentation of the surgical technique, intraoperative assessment of the surgical resection margin, the pathologic resection margin, and the estimated percentage of remaining renal parenchyma in each kidney at the conclusion of the procedure (Table 1) (24). Mrad et al demonstrated that patients with an estimated remaining renal parenchyma percentage of less than 50% had hypertension and detection of proteinuria at a median of eightyear follow-up (25). Such synoptic reporting of operative features may help standardize data reporting for comparison of oncologic and long-term renal function outcomes.…”