Retrospective analysis of outcomes in patients with clear cell sarcoma of the kidney: A tertiary single-institution experience

Background Clear cell sarcoma of the kidney (CCSK) is a rare and aggressive tumor. This study aims to describe the clinical characteristics and outcomes of CCSK patients in one of the largest pediatric medical centers in China. Methods We included all patients diagnosed with CCSK between January 2008 and March 2019 at the Children’s Hospital of Chongqing Medical University, China. The patients’ demographics, clinical presentation, and management were reviewed. Follow-up was continued until December 2019. Results In total, 41 CCSK patients (66% male) with a median age of 24 months (range 3-108 months) were identified. The stage distributions of stages I, II, III and IV were 42%, 34%, 24% and 0%, respectively. Preoperative chemotherapy was administered to 7/41 patients. All patients underwent radical nephrectomy and postoperative chemotherapy. The median number of lymph nodes sampled was 4 (range 1–12). Radiotherapy was applied in 8/41 patients. The 5-year event-free survival (EFS) and overall survival (OS) were 63.9% and 78.8%, respectively. Of the 41 patients, 11 patients experienced relapse at a median time of 19 months (range 5-72 months). The most common site of recurrence was the tumor bed (9/11). Young age was a significant adverse prognostic factor for EFS. Conclusions The overall outcome of CCSK patients in our hospital is poorer than that in developed regions. More research is needed to clarify the underlying causes of poorer outcomes in young patients and improve outcomes. Type of study Retrospective study. Level of evidence LEVEL IV.