Viable versus nonviable positive margins in Ewing sarcoma and associated recurrence rates: A systematic review

Residual tumor after curative intent therapy in patients with Ewing's sarcoma is of great clinical significance. Surgeons use the resection margin to indicate the completeness of a surgical excision. However, this margin may be either nonviable/necrotic or viable. This systematic review examines the 5-year event-free survival rate and local recurrence as a function of positive resection margins that are nonviable/necrotic versus those that are viable. Multiple databases were searched using the Ovid interface. After full text screening, 45 articles that reported either margin or postchemotherapy histology and one or more outcomes of interest were identified, and two articles reported on margin and histology simultaneously. An attempt was made to contact the remaining authors and one author was able to provide additional data. The data from the three studies suggest that prognosis in ES depends on both margin involvement and the postchemotherapy histological response simultaneously. However, radiation therapy likely improves local control in patients with inadequate surgical margins, regardless of histological response. This is an area where there is a paucity of evidence that needs to be rectified to ensure that ES patients are provided the highest quality of evidence-based care.