Poorer Outcome in Adults With Localized Ewing Sarcoma Compared With Children

Adults with localized Ewing sarcoma have a much lower rate of 5-year survival than do children, according to a retrospective study of adult patients managed at the Mayo Clinic in Rochester, Minnesota, over a 30-year period. The study found that children have a 5-year survival rate of about 75%, while adults with localized disease have a 5-year survival rate of 54%. The study was presented at the 2011 annual meeting of the American Society for Radiation Oncology (ASTRO).

“Local control and survival outcomes for adults with localized Ewing sarcoma are inferior to results in children. Local control is especially poor, suggesting that adults may need more aggressive local therapy [than children],” said the study’s lead author, Safia K. Ahmed, MD, medical student at the Mayo Clinic. “Outcomes for adults with metastatic disease are also inferior to pediatric patients, with a 10% 5-year overall survival in our study versus about 25% in pediatric patients with metastatic disease.”

Ahmed said that children are typically treated in a more uniform fashion with specific protocols in comparison to adults. “We don’t really have much data on how to treat adults. Improved outcomes in adults require more effective systemic therapy and a better understanding of the molecular and biologic differences between pediatric and adult Ewing sarcoma,” she said.

In the study, 42% of patients with localized disease had surgery, 22% had radiation therapy, and 35% had combined treatment of radiotherapy and surgery. Event-free survival (EFS) was 38% for localized disease and 9% for metastatic disease. The 5-year EFS for patients with localized disease who had surgery was 48% compared with 24% for radiotherapy, and 36% for the combination. The 5-year local failure and distant failure rates were 12% and 47%, respectively.

Of patients with metastatic disease, 12% had surgery of the primary tumor, 56% had radiation therapy, 10% had combined modality treatment, and the remaining 22% had no local treatment. Five-year EFS for metastatic patients who had surgery was 0% compared with 15% of those treated with radiation therapy, 0% for the combined modality treatment, and 0% for those with no local treatment. The 5-year local failure and distant failure rates were 36% and 87%, respectively.

The study was based on records of 163 adults with Ewing sarcoma; 122 (75%) presented with localized disease and 41 (25%) with metastatic disease. Two-thirds were male, and median age at diagnosis was 28 years. In patients with localized disease, the primary tumor site was an extremity in 46% of patients, the pelvis in 19%, and axial in 35%. The use of magnetic resonance imaging at diagnosis was associated with improved overall survival in these patients. Independent prognostic factors for survival in patients with metastatic disease included site of metastatic disease, site of primary tumor, and treatment before or after 1992.