Treatment patterns and survival outcomes of Ewing sarcoma in Ethiopia: a five-year retrospective analysis from a tertiary hospital

Abstract

BACKGROUND: Ewing sarcoma is a malignant small round-cell sarcoma of bone or soft tissue that is highly responsive to modern multimodal therapy and considered a highly curable disease in developed countries. However, survival remains poor in developing countries. This study aims to assess treatment patterns and survival outcomes of Ewing sarcoma at Tikur Anbessa Hospital. METHODS AND MATERIALS: We conducted a retrospective study on all patients diagnosed with Ewing sarcoma at Tikur Anbessa Hospital between November 15, 2018, and November 15, 2023. Descriptive statistics and Kaplan-Meier survival analysis were used to analyze the data. RESULT: The median age at diagnosis was 19 years, with most of the patients (67.2%) in the age range of 8-25 years. The main modality of treatment for localized disease was chemotherapy combined with surgery, whereas chemotherapy alone was used for metastatic disease. The Kaplan-Meier estimated 1-year and 3-year overall survival (OS) rates for the entire cohort were 96% and 68%, respectively, and the corresponding 1-year and 3-year event-free survival (EFS) rates were 70% and 40%, respectively. A sensitivity analysis treating loss to follow-up as events reduced the 3-year overall survival from 68% to 55% and the 3-year event-free survival from 40 to 33%. The 3-year OS and EFS rates were 89% and 76% for localized disease versus 10% and 0% for metastatic disease. This difference was statistically significant (log-rank p < 0.001). Small tumor size (≤ 8 cm), surgical intervention, and localized stage were associated with statistically significant improvements in OS and EFS, whereas pelvic location was associated with a poorer prognosis. CONCLUSION: Ewing sarcoma at our institution mainly affects adolescents and young adults. Survival is poor, especially for metastatic disease, while localized tumors, smaller size, and surgery are associated with better survival. Therefore, early diagnosis and improved multimodal treatment are needed to improve survival.