Nonviable Tumor Tissue Should Not Upstage Wilms' Tumor from Stage I to Stage II: A Report from the SIOP 93–01 Nephroblastoma Trial and Study

Abstract

In SIOP trials, Wilms' tumors were labeled as stage II by the presence of nonviable and/or viable tumor in the renal sinus and/or perirenal fat. The aim of this study was to determine if this approach was justified. Stage II Wilms' tumors were reviewed to establish whether staging was due to viable or nonviable tumor, and this was related to clinical outcome. One hundred sixty-nine patients were included: 40 had stage II due to the presence of nonviable tumor and 129 due to viable tumor. Postoperatively, 29 patients were undertreated: 7 with nonviable and 22 with viable stage II tumors. No undertreated patient with nonviable stage II relapsed or died (event-free survival [EFS] and overall survival [OS] 100%), whereas 3 of 22 with viable stage II relapsed, and 2 of them died (EFS 86%, OS 91%). Of 140 correctly treated patients, only 1 of 33 nonviable stage II patients relapsed and died (EFS and OS 97%); 8 of 107 patients with viable stage II relapsed (EFS 92%), and 3 of them died (OS 97%). The presence of nonviable tumor in the renal sinus and/or perirenal fat does not predict an adverse outcome in Wilms' tumors, and alone it does not warrant designation to stage II.

The effect of preoperative chemotherapy on histological subtyping and staging of Wilms tumors: The United Kingdom Children's Cancer Study Group (UKCCSG) Wilms tumor trial 3 (UKW3) experience

“…13,23 Preoperative chemotherapy does require a more complicated staging system, but it also downstages tumors, resulting in less postoperative treatment. 14,24 In addition to bilateral and metastatic tumors which were excluded because their preoperative treatment is longer and more aggressive, anaplastic WTs were also excluded from detailed analysis because they are regarded as chemotherapy-resistant and this group was not included in other similar studies with which we compared our results. 11,12 Our study is unique because it included two groups that are not usually covered by other studies.…”

“…Nephrogenic rests are often preserved after standard preoperative chemotherapy, which is a clue to the diagnosis of WT in a completely necrotic tumor . Preoperative chemotherapy does require a more complicated staging system, but it also downstages tumors, resulting in less postoperative treatment …”

Dataset for the reporting of nephrectomy specimens for Wilms' tumour treated with preoperative chemotherapy: recommendations from the International Society of Paediatric Oncology Renal Tumour Study Group

“…However, later studies showed that this finding in the renal sinus (Figure 2) and perirenal fat could be ignored (resulting in more stage I tumours but maintaining excellent survival). 12 Recently, it has been shown that the presence of CICs at the non-vascular (i.e. the renal vein and inferior vena cava) resection margins can also be ignored as a criterion for stage III.…”

Tumeurs du rein de l’enfant et de l’adolescent

“…Le traitement postopératoire dépend de deux critères : le type histologique et le stade d'extension locale [8,9]. À ce jour, les premiers résultats montrent qu'environ 10 % des patients de stade 1 ou 2 et 13 % des patients avec histologie de risque intermédiaire récidivent, voire décèdent.…”