Maintenance Chemotherapy in Patients With High-Risk Rhabdomyosarcoma: Long-Term Survival Analysis of the European <i>Paediatric</i> Soft Tissue Sarcoma Study Group RMS 2005 Trial.

Abstract

The European Paediatric Soft Tissue Sarcoma Study Group (EpSSG) RMS 2005 trial evaluated maintenance chemotherapy in high-risk rhabdomyosarcoma (RMS). Patients were randomly assigned to either discontinue treatment (standard arm) or receive six 28-day cycles of vinorelbine (25 mg/m²) once per day on days 1, 8, and 15, plus once daily low-dose cyclophosphamide (25 mg/m²; experimental arm). Initial results showed improved overall survival (OS), but disease-free survival (DFS) improvement was not statistically significant. This report presents mature survival outcomes after extended follow-up. Between April 2006 and December 2016, 186 patients were enrolled in the standard arm and 185 in the experimental arm. After a median follow-up of 122.1 months from diagnosis and 114 months from random assignment, recurrence, progression, or death occurred in 103 patients (61 standard arm, 42 experimental arm). The 10-year DFS was 66.5% (95% CI, 59 to 74) in the standard arm versus 77.1% (95% CI, 70.3 to 82.5) in the experimental arm (<i>P</i> = .025). Corresponding 10-year OS rates were 70.8% (95% CI, 63.3 to 77.0) and 82.9% (95% CI, 76.6 to 87.7; <i>P</i> = .0099). Long-term results of the RMS2005 trial confirm the survival benefit of maintenance chemotherapy with vinorelbine and low-dose cyclophosphamide for patients with high-risk RMS.