Reappraisal of prognostic factors used in the European Pediatric Soft Tissue Sarcoma Study Group RMS 2005 study for localized rhabdomyosarcoma to optimize risk stratification and generate a prognostic nomogram.

This study used data from patients enrolled in the EpSSG RMS 2005 study to investigate the role of traditional clinical factors together with FOXO1 fusion status in non-metastatic rhabdomyosarcoma with the aim to develop a predictive model for event-free survival and provide a rationale for risk stratification for future trials. The multivariable model retained 5 prognostic factors including age at diagnosis interacting with tumor size, tumor primary site, IRS group, and FOXO1 fusion status. Based on each patient's total score in the nomogram, patients were stratified into four groups. The 5-year EFS rates were 94.1%, 78.4%, 65.2%, and 52.1%, respectively, in low-, intermediate-, high-, and very high-risk groups. The corresponding 5-year OS rates were 97.2%, 91.5%, 74.3%, and 60.8%. The most important result is the replacement of histology with fusion status and this model was utilized for the patient stratification in the new FaR RMS trial.