The clinical relevance of age at presentation in nephroblastoma

Abstract

The most important prognostic factors for Wilms tumor (WT) patients seem to be stage, histological subtype, and 1p/16q loss of heterozygosity (LOH) in chemotherapy-naive WTs. Over the last decade, age at diagnosis also was suggested to be an important risk factor for WT recurrence in Children's Oncology Group (COG), United Kingdom (UK), and International Society of Pediatric Oncology (SIOP) studies. Several studies have analyzed age as a prognostic factor; these studies revealed age <2 years as a favorable prognostic factor, while age >4 years has been described as an adverse prognostic factor. In adults (>18 years of age), WT represents less than 1% of all diagnosed renal tumors; therefore, diagnosis of WT in adults is often unexpected and poorly recognized, thereby inducing treatment delay with subsequent adverse outcome. One explanation for the higher risk of recurrence with increasing patient age is the higher frequency of anaplasia at higher age. Other suggested reasons are delay in diagnosis, advanced tumor stage at presentation, and intrinsically different biological behaviors. Whether age is really an independent risk factor, and whether age is a stronger prognostic factor than stage, histology, and LOH 1p/16q, needs to be further explored. This may provide some insight into whether older patients need to be treated more intensively, as is already advised for adult WT patients.