Factors associated with relapse/progression in pediatric trunk and extremity rhabdomyosarcoma

Rhabdomyosarcoma (RMS) of the trunk and extremities is associated with unfavorable outcomes due to high rates of metastasis and relapse. However, large-scale studies focusing specifically on this anatomical subsite remain limited. This study aimed to investigate the clinical characteristics and risk factors associated with relapse/progression in pediatric patients with trunk and extremity RMS.

To investigate the clinical features and risk factors associated with relapse/progression in pediatric patients with rhabdomyosarcoma (RMS) of the trunk and extremities.

A retrospective analysis was conducted on clinical data from 15 children with trunk and extremity RMS treated at Shanghai Children's Hospital between January 2011 and December 2024. All patients received multimodal therapy, including surgery, chemotherapy, and radiotherapy. Associations between clinical characteristics and relapse/progression rates were analyzed using descriptive statistics and Fisher's exact test.

The median follow-up duration was 48 months. The 5-year event-free survival (EFS) was 60% (95% CI: 34.5%-85.5%), and the 5-year overall survival (OS) was 66.7% (95% CI: 42.1%-91.3%). The overall relapse/progression rate was 40% (95% CI: 16.8%-68.7%). Significantly higher relapse/progression rates were observed in patients with metastasis at diagnosis (85.7% vs 0%, P<0.001), high-risk stratification (75.0% vs 0%, P=0.010), and macroscopic residual disease after surgery (100% vs 10.0%, P<0.001). Regional lymph node involvement showed a trend toward a higher relapse/progression rate (66.7%) compared to no involvement (22.2%), although the difference was not statistically significant (P=0.123).

Pediatric trunk and extremity RMS is associated with a high risk of relapse/progression. Metastasis at diagnosis and macroscopic residual tumor after resection are major adverse prognostic factors. Regional lymph node involvement may confer an increased risk, warranting validation in larger cohorts.