P4.065: Clinical Outcomes and Demographic Factors in Pediatric Rhabdomyosarcoma: A Comprehensive Analysis of the SEER Database

Background: Rhabdomyosarcoma (RMS) is a rare and aggressive malignancy originating from mesenchymal cells that differentiate into striated muscle. It is the most common soft tissue sarcoma in children, with peak occurrence between ages 1 and 5. RMS is classified into two main subtypes: embryonal (ERMS), which has a better prognosis, and alveolar (ARMS), which is associated with worse outcomes due to chromosomal translocations. This study aims to analyze survival outcomes in pediatric RMS patients from 2000 to 2021, focusing on the impact of demographic and therapeutic variables.

Methods: A retrospective cohort study was conducted using the Surveillance, Epidemiology, and End Results (SEER) database, spanning 22 registries and including 452 pediatric RMS patients. Demographic variables such as age, race, laterality, and rural/urban status were analyzed alongside treatment modalities (surgery and radiotherapy) and time to treatment. Statistical analyses included Kaplan-Meier survival analysis for outcome comparisons, Cox proportional hazards models for mortality risk assessment, and the Kruskal-Wallis test with Dwass, Steel, Critchlow-Fligner Method for evaluating age, stage, and geographic variations. A significance threshold of p < 0.05 was applied.

Results: Laterality, race, rural/urban status, and year of diagnosis significantly influenced survival outcomes. Left-sided and midline tumors were associated with higher mortality risks (p = 0.003, p = 0.019). White and Hispanic patients had significantly higher mortality risks (p = 0.008, p = 0.006). Nonmetropolitan counties not adjacent to a metropolitan area showed increased mortality risk (p < 0.001). Each additional year of diagnosis without treatment increased hazard risk (p = 0.026, HR = 1.184). Surgery significantly reduced mortality risk (p < 2e-16, HR = 0.9839), and radiation therapy decreased adverse outcomes by 8.3% (p = 3.2e-11, HR = 0.9171).

Conclusion: Demographic and treatment-related factors significantly impact pediatric RMS survival. Left-sided and midline tumors, White and Hispanic racial backgrounds, and rural residence correlate with poorer outcomes. Delayed diagnosis increases mortality risk, while surgical and radiotherapy interventions improve prognosis. Future research should focus on improving early detection, addressing geographic treatment disparities, and incorporating molecular profiling to refine risk stratification and treatment strategies.