Clear cell sarcoma of the kidney in Austrian children: Long-term survival after relapse.

Abstract

Clear cell sarcoma of the kidney (CCSK) is a rare malignant childhood renal tumour. Recently, the central nervous system (CNS) was found to be the most frequent site of relapse associated with a poor outcome. Optimal treatment strategies are scarce. Retrospective data analysis of all Austrian children with CCSK. They were enrolled in the Austrian-Hungarian Wilms Tumour Study (AHWTS) 1989, the SIOP93-01 or the SIOP2001 study between 1990 and 2019. Demographic, diagnostic, treatment-related variables and survival data were analysed. We identified 12 children with CCSK (M=7, F=5; median age 1.6years). All had localised disease (stage I: 2; stage II: 2; stage III: 8) at diagnosis, and a first complete remission (CR1) was achieved in 12/12. Six patients are in an ongoing CR1 (median follow-up 10years). Six other patients had a relapse (local 1; brain 5) a median time of 2.4years from diagnosis. Two patients died of the disease 4months and 2.8years after first relapse. Four of five patients with CNS relapse are in CR2 with a median follow-up time of 9.3years after relapse diagnosis. Relapse treatment included a combination of chemotherapy, radiation and surgery. Two children received high-dose chemotherapy followed by autologous stem cell rescue, and one child received intrathecal mafosphamide. Long-term side effects after treatment were impaired tubular renal function (n=4), cardiomyopathy (n=1) and growth disorders (n=1). In this series, the brain was the most common site of relapse. Long-term survival after recurrence was achievable with intensive multimodal therapy.