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

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/m 2 ) once per day on days 1, 8, and 15, plus once daily low-dose cyclophosphamide (25 mg/m 2 ; 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 ( P = .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; P = .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.