Introduction: The data on outcomes and toxicity in adult Ewing sarcoma (ES) patients, particularly those aged ≥40 years, is exceedingly scarce around the world, particularly in low- and middle-income countries (LMICs) and mandates research.

Methods: The study involved histologically ascertained ES patients aged ≥40 years who registered at our institute from 2013 to 2018. Prospectively collected data were analysed for overall survival (OS), event-free survival (EFS) and chemotherapy-related toxicities.

Results: There were 66 patients, of which 34 were non-metastatic, and 32 were denovo metastatic, recurrent or had doubtful metastasis. At presentation, median age was 46 years, and 42 (63.6%) had extra-skeletal primary and 24 (36.3%) had extremity tumours. Curative treatment was offered to 40 (60.6%) patients. Significant grade 3/4 toxicities in non-metastatic and metastatic cohort, respectively, were febrile neutropenia (61.3%, 37.5%), anaemia (58.1%, 37.5%), thrombocytopenia (45.2%, 25.0%), peripheral neuropathy (25.8%, 12.5%) and dyselectrolytemia (25.8%, 6.25%). Chemotherapy-related toxicity led to death in three patients in the metastatic cohort, versus none in the non-metastatic patients. The 5 year EFS and OS for non-metastatic cohort were 53.8% and 67.8%, while the same for metastatic cohort were 20.7% and 27.5%, respectively. On multivariate analysis, Eastern Cooperative Oncology Group-performance status >2 and metastasis at presentation predicted poorer EFS and OS. Additionally, raised lactate dehydrogenase, larger tumours (>8 cm) and palliative intent treatment predicted worse EFS, while extra-skeletal primary and female gender were indicators of worse OS.

Conclusions: Older adult ES patients benefit from aggressive multimodality treatment even in LMIC infrastructure. However, careful patient selection, close monitoring and pertinent dose modifications is imperative due to higher propensity for potential toxicities.