Characteristics and Outcomes in Pediatric Non-Central Nervous System Malignant Rhabdoid Tumors: A Report from the National Cancer Database

Background: Pediatric non-central nervous system (CNS) malignant rhabdoid tumors (MRTs) are rare and aggressive malignancies without standard treatment strategies. The National Cancer Database (NCDB) was utilized to describe the incidence, characteristics, treatment strategies, and outcomes in pediatric patients. Methods: Patients <18 years of age and diagnosed with non-CNS MRTs were analyzed from the NCDB from 2004 to 2014. Log-rank tests compared differences in Kaplan–Meier survival distributions. Univariate and multivariable Cox proportional hazard regression models identified predictors of mortality. Results: Overall, 202 patients were identified. Soft tissue tumors were most common and metastatic disease was present at diagnosis in 34.2% of patients. The 1- and 5-year overall survival (OS) rates were 48.8% and 35.9%, respectively. Multivariable analysis revealed that age <1 year and the presence of metastasis were negative prognostic indicators (p = 0.058). The 1- and 5-year OS rates were 59.9% and 46.5%, respectively, for patients who received surgical intervention (n = 143) compared with 12.3% and 7.4%, respectively, for those treated nonoperatively (n = 59; p < 0.01). Surgical resection was associated with improved outcomes on univariate analysis, although it was no longer an independent predictor of survival on multivariate analysis (p = 0.18). In the cohort of surgical patients, the presence of residual disease trended towards clinically significant worse outcomes (p = 0.13). Conclusions: Patients with non-CNS MRTs who were diagnosed in infancy and had metastatic disease had worse survival outcomes. Although surgical resection was associated with improved survival in non-CNS MRTs, it was not independently associated with survival on multivariate analysis. Efforts to improve survival may instead depend on improving chemotherapeutic strategies and developing targeted therapies.