ABSTRACT
Maintenance chemotherapy (MC) defines the administration of prolonged relatively low-intensity chemotherapy with the aim of "maintaining" tumor complete remission. This paper aims to report an update of the RMS2005 trial, which demonstrated better survival for patients with high-risk localized rhabdomyosarcoma (RMS) when MC with vinorelbine and low-dose cyclophosphamide was added to standard chemotherapy, and to discuss the published experience on MC in RMS. In the RMS2005 study, the outcome for patients receiving MC vs. those who stopped the treatment remains superior, with a 5-year disease-free survival of 78.1% vs. 70.1% (p = 0.056) and overall survival of 85.0% vs. 72.4% (p = 0.008), respectively. We found seven papers describing MC in RMS, but only one randomized trial that did not demonstrate any advantage when MC with eight courses of trofosfamide/idarubicine alternating with trofosfamide/etoposide has been employed in high-risk RMS. The use of MC showed better results in comparison to high-dose chemotherapy in non-randomized studies, including metastatic patients, and demonstrated feasibility and tolerability in relapsed RMS. Many aspects of MC in RMS need to be investigated, including the best drug combination and the optimal duration. The ongoing EpSSG trial will try to answer some of these questions.
ABSTRACT
Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The RMS2005 study included two phase III randomized trials for high-risk (HR) and observational trials for low (LR), standard (SR), and very high-risk (VHR) patients who have been partially reported. Herein, we present a comprehensive report of results achieved for the complete unselected nonmetastatic cohort and analyze the evolution of treatment in comparison with previous European protocols. After a median follow-up of 73.1 months, the 5-year event-free survival (EFS) and overall survival (OS) of the 1,733 patients enrolled were 70.7% (95% CI, 68.5 to 72.8) and 80.4% (95% CI, 78.4 to 82.3), respectively. The results by subgroup: LR (80 patients) EFS 93.7% (95% CI, 85.5 to 97.3), OS 96.7% (95% CI, 87.2 to 99.2); SR (652 patients) EFS 77.4% (95% CI, 73.9 to 80.5), OS 90.6% (95% CI, 87.9 to 92.7); HR (851 patients) EFS 67.3% (95% CI, 64.0 to 70.4), OS 76.7% (95% CI, 73.6 to 79.4); and VHR (150 patients) EFS 48.8% (95% CI, 40.4 to 56.7), OS 49.7% (95% CI, 40.8 to 57.9). The RMS2005 study demonstrated that 80% of children with localized rhabdomyosarcoma could be long-term survivors. The study has established the standard of care across the European pediatric Soft tissue sarcoma Study Group countries with the confirmation of a 22-week vincristine/actinomycin D regimen for LR patients, the reduction of the cumulative ifosfamide dose in the SR group, and for HR disease, the omission of doxorubicin and the addition of maintenance chemotherapy.