Effect of risk group on survival in non-Wilms' renal tumors in children

Purpose: The aim of this study was to evaluate tne effect of the risk group on the clinical features of the disease, treatment strategies and especially survival in children with Non-Wilms’ renal tumors (NWRTs). 
Materials and Methods: Patients diagnosed with NWRTs followed up and treated between January 2012 and January 2022 were included in the study (n=29; 16 boys and 13 girls). They were categorized into high- and low-risk groups based on their histological type. Patient records were reviewed retrospectively. Clinical characteristics, treatments, and outcomes of these patients were analyzed. 
Results: The high-risk group comprised clear cell sarcoma (CCSK) (n=8, 27.6%), malignant rhabdoid tumor (MRT) (n=3, 10.3%), renal cell carcinoma (n=2, 6.9%), non-Hodgkin lymphoma (n=1, 3.4%), and primitive neuroectodermal tumor (PNET) (n=1, 4%). The low-risk group comprised congenital mesoblastic nephroma (CMN) (n=9, 31%), angiomyolipoma (n=4, 3.8%), and hemangioma (n=1, 3.4%). Five patients died due to disease progression (mortality rate, 17%), all of whom belonged to the high-risk group (three patients with MRT, one with CCSK, one with PNET). The 5-year survival rate was 72% for the high risk group and 100% for the low risk group. 
Conclusion: Although low-risk tumors are associated with excellent outcomes, the outcomes vary in high-risk tumors. Physicians should be wary of high mortality rates in children with MRT, CCSK, and PNET, and should design multidisciplinary treatments for NWRTs.