Pediatric rhabdomyosarcoma incidence and survival in the United States: An assessment of 5656 cases, 2001–2017

BACKGROUND: While rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents, past epidemiology studies of this malignancy used data that covered <30% of the US population. Therefore, we evaluated RMS incidence using data from U.S. Cancer Statistics (USCS) and survival trends using the National Program of Cancer Registries (NPCR), which covers 100% and 94% of the U.S. population, respectively. METHODS: Incidence and survival were assessed for pediatric patients diagnosed with RMS during 2003–2017 and 2001–2016, respectively. Both demographic and clinical variables were evaluated. Age‐adjusted incidence rates, average annual percent change (AAPC), and 5‐year relative survival (RS) were calculated, all with corresponding 95% confidence intervals (CIs). Cox regression models were used to evaluate the impact of demographic and clinical variables on survival. RESULTS: We identified 5656 primary RMS cases in USCS during 2003–2017. The age‐adjusted incidence rate was 4.58 per 1 million (95% CI: 4.46–4.70) with an AAPC of 0.3% (95% CI: −0.7 to 1.2%). In NPCR, 5‐year RS for all cases was 68.0% (95% CI: 66.6–69.3%). In multivariable analyses, non‐Hispanic (NH) Black cases had worse survival compared with NH White cases (hazard ratio [HR] = 1.16, 95% CI: 1.01–1.33). CONCLUSION: The incidence and survival rates were stable in the largest and most comprehensive population‐based analysis for pediatric RMS cases in the U.S. Additionally, we observed a survival disparity among NH Black cases. Findings from this study could inform interventions to address disparities, risk stratification strategies, and clinical trial design.