Surgical Cytoreduction and Intraoperative Microwave Ablation in Pediatric Desmoplastic Small Round Cell Tumor: A 24-Year Single-Center Experience.

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive pediatric malignancy, and optimal management remains challenging because most patients present with metastatic disease, and evidence guiding multimodal treatment is limited. We retrospectively reviewed 11 children with DSRCT treated at our institution between 2000 and 2023. Demographics, tumor characteristics, treatment modalities-including neoadjuvant chemotherapy, surgical resection, and intraoperative microwave ablation (MWA)-and outcomes were analyzed. Tumor burden was assessed using the Peritoneal Cancer Index (PCI), and survival was estimated using the Kaplan-Meier method. The median age at diagnosis was 11.6 years (male-to-female ratio, 2.6:1). Primary tumors were abdominopelvic (45.5%), pelvic (36.4%), or abdominal (18.2%). Lymphadenopathy occurred in 91% of patients, and 55% had extranodal metastases, predominantly hepatic. After chemotherapy, all patients underwent surgery: complete resection (R0) in 3, partial excision in 8, and intraoperative MWA for liver metastases in 2. The median follow-up was 26 months. The 5-year overall and event-free survival rates were 47% and 30%, respectively, and R0 resection was strongly associated with disease-free survival. Aggressive surgical cytoreduction remains central to improving outcomes in pediatric DSRCT. Intraoperative MWA may be a safe adjunct for selected patients with hepatic metastases. PCI appears useful for quantifying tumor burden, although validation in larger cohorts is warranted.