High-dose Chemotherapy Response in Adults with Relapsed/Refractory Small Round Cell Tumours.

ABSTRACT

OBJECTIVE: To demonstrate the treatment responses, survival analysis, and treatment-related mortality characteristics of high-dose chemotherapy (HDC) in patients with relapsed/refractory Ewing sarcoma (ES), osteosarcoma, rhabdomyosarcoma (RMS) and medulloblastoma (MB). STUDY DESIGN: Observational study. PLACE AND DURATION OF STUDY Department of Medical Oncology, University of Health Sciences, Gulhane School of Medicine, from January 2016 and April 2020. METHODOLOGY: Clinical features and follow-up data of relapsed/refractory ES, osteosarcoma, RMS and MB patients treated with HDC were recorded from the patients' registration database of the hospital. Patients <16 years and those whose medical records were not available were excluded. Progression-free survival (PFS), one-year overall survival (OS) rates and treatment-related mortality (TRM) after the HDC were determined. Ifosfamide, carboplatin and etoposide (HD-ICE) were used as the HDC protocol in all patients. RESULTS: Thirty-seven adult patients were included. PFS was determined as 2.70 ± 0.97 months, 11.57 ± 3.63 months, 3.47 ± 0.44 months and 2.96 ± 0.91 months, for ES, MB, RMS and osteosarcoma, respectively. One-year OS rate was 44.8 ± 14.8% for ES; 75 ± 15.8% for MB. In ES, PFS was found to be better in males than females (p = 0.025). No patient died during HD-ICE. Mortality was observed most frequently in the RMS in the first 100 days (25%). CONCLUSION: HD-ICE treatment may be an option in relapsed/refractory small round cell tumours (SRCT). Significant progression-free survival can be achieved in patients who received at least two lines of treatment, with acceptable treatment-related mortality. Key Words Small round cell tumours, Ewing sarcoma, Osteosarcoma, Rhabdomyosarcoma, Medulloblastoma, High-dose chemotherapy, Autologous stem cell transplantation.