Impact of Whole Lung Irradiation on Survival Outcome in Patients With Lung Relapsed Ewing Sarcoma

Abstract

There is no standard treatment procedure for relapsed Ewing sarcoma (EwS). This retrospective analysis evaluates the survival outcome in patients with an isolated pulmonary relapse of EwS treated with whole lung irradiation (WLI) in addition to second line chemotherapy (Ctx). In our study, 136 patients with pulmonary relapsed EwS who were registered in the relapse register of the Cooperative Ewing Sarcoma Study group or the Sarcoma Relapse Registry for relapsed sarcoma of bone and soft tissues were analyzed. All patients received relapse Ctx or an additional total resection of lung metastasis. Of these patients, 88 (median age, 21years; range, 7-52years) achieved a second remission by the relapse treatment. Of these 88 patients, 48 patients received an additional WLI. The 3-year progression-free survival (PFS) and 3-year overall survival (OS) were analyzed (median follow-up, 3years; range, 7months to 11years and 9months). Additional prognostic factors for survival outcomes, including the response of lung metastases to Ctx, were also estimated. The survival outcome was significantly improved after WLI when analyzing the entire group of pulmonary relapsed patients: 3-year PFS 36% (+WLI) versus 14% (-WLI) (P=.001); 3- year OS 47% (+WLI) versus 33% (-WLI) (P=.007). The 3-year PFS in patients with complete remission of lung relapse receiving WLI (n=48) compared with those without WLI (n=40), was 37% (+WLI) versus 21% (-WLI) (P=.18). The site of the primary tumor and the response of pulmonary lesions to Ctx were significant prognostic indicators for survival in patients treated with WLI. No severe pulmonary function disorders or lung toxicities were observed after WLI treatment in both pediatric and adult patients. The WLI does not correlate with improved OS in patients with pulmonary relapsed EwS. However, a marginal trend toward superior PFS and improved local control of pulmonary disease suggests the application of WLI in patients with EwS with isolated lung relapse and second clinical remission.