Dr Randall on Drivers of Local Recurrence Risk in Nonmetastatic Ewing Sarcoma

“The overall 5-year cumulative incidence of local recurrence was just 6%... This is the lowest reported rate to date in a prospective Ewing sarcoma trial. [These findings reinforce] the principle that tumor size and disease burden remain dominant drivers of risk even in the modern era."

R. Lor Randall, MD, FACS, the David Linn Endowed Chair for Orthopedic Surgery, the chair of the Department of Orthopedic Surgery, and a professor at UC Davis Comprehensive Cancer Center, discussed key findings from a contemporary analysis of clinical and treatment variables associated with local recurrence risk in patients with nonmetastatic Ewing sarcoma treated with interval compression therapy in the phase 3 AEWS1031 study (NCT01231906).

The analysis included 588 patients with nonmetastatic Ewing sarcoma who received interval compression chemotherapy to determine which clinical and treatment variables influence the risk of local recurrence. Randall reported that the overall 5-year cumulative incidence of local recurrence was 6%, representing the lowest rate recorded in a prospective Ewing sarcoma trial to date.

A major takeaway from the study was that the local therapy modality—whether surgery alone, radiation alone, or a combination of both—did not significantly impact 5-year local recurrence rates. These rates were 5% for surgery, 8.4% for radiation, and 5.6% for the combination, with no significant difference observed between the groups. Randall noted that this represents meaningful progress, as outcomes with modern radiation delivery appear substantially improved compared with historical datasets.

Crucially, the strongest predictors of local failure were related to tumor biology and disease burden rather than the chosen treatment modality. Multivariate analysis identified 3 dominant risk factors: tumor volume greater than 200 mL, a maximum tumor dimension of 8 cm or larger, and older age at enrollment. Additionally, axial tumor location was associated with a higher risk compared with extremity tumors. For instance, patients with tumors larger than 200 mL had an 11% recurrence rate and those with smaller tumors had a recurrence rate of 3.9%.

Regarding systemic therapy, patients receiving VDC-IE—vincristine, doxorubicin (Adriamycin), and cyclophosphamide (Cytoxan) alternating with ifosfamide (Ifex) and etoposide (Toposar)—plus VTC (vincristine, topotecan, and cyclophosphamide) showed numerically lower recurrence rates than those on VDC-IE alone. Randall concluded that these findings support individualized decision-making based on resectability and function, as radiation provides comparable control to surgery in the modern era.