Maintenance Chemotherapy for Patients with Rhabdomyosarcoma

SIMPLE SUMMARY: The updated results of the RMS2005 randomized study confirm that patients with non-metastatic high risk rhabdomyosarcoma have an improved survival when maintenance chemotherapy (MC) with vinorelbine and low dose cyclophosphamide is added to the standard multidisciplinary treatment. A more recent randomized study adopted the same strategy, but different drugs were used in the MC phase (trofosfamide, idarubicin and etoposide). No survival improvement was evident in the MC group, suggesting that not all types of MC are equally effective. A revision of the literature demonstrates that the role of MC in patients with metastatic or relapsed RMS may be a promising approach but need more investigations. 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.