Safety and Tolerability of Interval Compressed Chemotherapy Schedule in Children Receiving Treatment for Ewing Sarcoma: A Real-world Experience From India.

Background and aims: Chemotherapy with alternating cycles of vincristine-doxorubicin-cyclophosphamide and ifosfamide-etoposide, along with primary tumor treatment with surgery or radiotherapy or both, constitute the usual treatment of Ewing sarcoma. The AEWS0031 study demonstrated survival benefits after interval-compressed chemotherapy without significant toxicity. The aim of this study was to assess the tolerability of dose-intensified chemotherapy in developing countries like India.

Methods: This was a retrospective analysis of children younger than 18 years of age with newly diagnosed Ewing sarcoma who came for treatment from December 2017 to December 2022. Children received vincristine (2 mg/m 2 ), doxorubicin (75 mg/m 2 ), and cyclophosphamide (1.2 g/m 2 ) alternating with ifosfamide (9 g/m 2 ), etoposide (500 mg/m 2 ) for 17 cycles, with filgrastim (5 µg/kg; maximum 300 µg) between cycles. Primary tumor treatment was provided with surgery or radiotherapy or both. Local treatment was given between weeks 12 to 16. Toxicity was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) Version 3.0. Radiologic response assessment was carried out with restaging CT or MRI scans after 6 to 8 cycles of chemotherapy in nonmetastatic and metastatic settings, respectively.

Results: Thirty-one children were enrolled. Twenty-three children received all 17 cycles of chemotherapy. The median cycle interval was 18 days and 41% of children received chemotherapy at the 2-week interval. Grade 4 febrile neutropenia was observed in 32% of cycles but no treatment-related mortality was reported. Anemia and thrombocytopenia requiring transfusion support were recorded in 28 (5.6%) and 69 cycles (13.9%) of chemotherapy, respectively. There were 2 events of grade 4 cardiac toxicities in the form of cardiomyopathy and arrhythmia requiring intensive care management. After surgery, good necrosis was achieved in 61% of cases. Three children had a relapse with an event-free survival (EFS) of 87%.

Conclusion: Intensified chemotherapy administered every 2 weeks intervals in Ewing sarcoma, is tolerable with adequate supportive care in resource-constrained settings.