Association of chemotherapy dose intensity and age with outcomes in patients with Ewing's family sarcoma

Abstract

BACKGROUND: Ewing's family sarcoma (EFS) is an aggressive malignancy with a peak incidence in adolescents. Multimodal treatment involves surgery and/or radiotherapy, and chemotherapy typically with VDC/IE (vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide). There is a paucity of data for the treatment of adults, with protocols extrapolated from the pediatric setting. This study aimed to assess patterns of care, chemotherapy tolerability across age groups, and outcomes from four Australian sarcoma centers. METHODS: ANZSA ACCORD sarcoma database and medical records were used to identify and collect data of patients aged ≥ 10 years with EFS who received VDC/IE between 2010 and 2020. Survival outcomes were analyzed based on chemotherapy received dose intensity (RDI). Clinical predictors of RDI were explored using logistic regression. RESULTS: Of 146 patients with EFS, 76 received VDC/IE. The majority had localized disease (65%). Seventy-one percent completed scheduled chemotherapy, with some requiring dose reduction (29%), delay > 7 days (65%), or cycle omission (4%). Hematological toxicity was the main reason for dose reduction/delay. Fifty-seven percent patients achieved an acceptable RDI ≥85%. Compared to those aged 10-19, the odds ratio for acceptable RDI aged 40-59 was 0.20 (95% CI 0.04-0.86, p = 0.04). RDI was an independent prognostic factor for overall survival, after accounting for age, gender, Ewing's type, primary site, and stage (adjusted HR 0.25 [95% CI 0.10-0.63], p = 0.004). CONCLUSION: Survival outcomes in EFS were associated with chemotherapy RDI. Older adults more commonly required dose reduction or early cessation of treatment due to toxicity. VDC/IE chemotherapy should be carefully tailored in adults > 40 years