Clear cell sarcoma of the kidney in children: clinical characteristics and treatment results

Abstract

Clear cell sarcoma of the kidney (CCSK) is a rare malignant renal tumor in children, which accounts for 2–5% of pediatric kidney malignancies. The aim of the study was to analyze the results of therapy of patients with CCSK treated in Dmitry Rogachev National Medical Research Center оf Pediatric Hematology, Oncology and Immunology. Retrospective analysis of patients with a histologically confirmed diagnosis of CCSK treated for the period 01.2012–02.2020 (98 months) was done. The study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI of the Ministry of Healthcare of the Russian Federation. Demographic characteristics, clinical symptoms, methods of diagnosis, and treatment modalities were analyzed. Patients were treated according to the protocols of the SIOP-RTSG group (SIOP 93-01, SIOP-2001, SIOP-RTSG-2016). The stage was assigned according to the SIOP classification. Overall and event-free survival was assessed by the Kaplan–Mayer method. The analysis of the results was carried out on 01.03.2021. The analysis included 10 patients with CCSK. The median age at the time of diagnosis of CCSK was 30.1 months (range 13.5–70.8 months). All patients were male. The duration from the onset of the first symptoms/detection of the tumor to the diagnosis was 0.8 months (range 0.1–3.2 months). The diagnosis was established on the basis of clinical and radiological data (n = 9) and biopsy (n = 1). Distant metastases at the time of diagnosis were detected in 1 (10%) patient (localization of metastases - lungs). The median tumor volume was 439 cm3 (range 256–996 cm3 ). Preoperative chemotherapy was performed in all patients (AV regimen (actinomycin D, doxorubicin) in 7 (70%) patients). Assessment of response after preoperative chemotherapy showed tumor regression in 3/10 (in 1/7 with AV regimen), tumor progression in 5 and stable disease in 2 patients. Surgical treatment in the extent of nephrectomy was performed in all patients. In 1 (10%) case, intraoperative tumor rupture was documented. Distribution of patients by local stages: I – 4/10 (40%), II – 2/10 (20%), III – 4/10 (40%) (including 1 patient with distant metastases). In 1 patient, a left thoracotomy was performed to exclude lung metastases. Adjuvant chemotherapy was performed in all patients in accordance with the relevant protocols of the high-risk group: 7 – 4–5-drug regimen, 3 – AVD regimen (actinomycin D, vincristine, doxorubicin). Radiation therapy was performed in 6/10 (60%) patients. Outcomes: 9/10 (90%) – alive, 1/10 (10%) patient died (non-tumor-related death). 3-year event-free survival and overall survival were 78.8% (95% confidence interval (CI) 52.5–100) and 90.0% (95% CI 71.4–100) respectively. Intensive program therapy in patients with CCSK allows to achieve satisfactory results of treatment.