Extraskeletal Ewing Sarcomas in Late Adolescence and Adults: A Study of 37 Patients

Background: Extraskeletal Ewing sarcoma (EES)/primitive neuroectodermal tumours (PNET) are raresoft tissue sarcomas. Prognostic factors and optimal therapy are still unconfirmed. Materials and
Methods:We performed a retrospective analysis on patients to explore the clinic characteristics and prognostic factorsof this rare disease. A total of 37 patients older than 15 years referred to our institute from Jan., 2002 to Jan.,2012 were reviewed. The characteristics, treatment and outcome were collected and analyzed.
Results: Themedian age was 28 years (range 15-65); the median size of primary tumours was 8.2 cm (range 2–19). Sixteenpatients (43%) had metastatic disease at the initial presentation. Wide surgical margins were achieved in 14 cases(38%). Anthracycline or platinum-based chemotherapy was performed on 29 patients (74%). Radiotherapy wasdelivered in 13 (35%). At a median follow-up visit of 24 months (range 2–81), the media event-free survival (EFS)and overall survival (OS) were 15.8 and 30.2 months, respectively. The 3-year EFS and OS rates were 24% and43%, respectively. Metastases at presentation and wide surgical margins were significantly associated with OSand EFS. Tumour size was significantly associated with OS but not EFS. There were no significant differencesbetween anthracycline and platinum based chemotherapy regarding EFS and OS.
Conclusions: EES/PNET is amalignant tumour with high recurrence and frequent distant metastasis. Multimodality therapy featuring widesurgical margins, aggressive chemotherapy and adjuvant local radiotherapy is necessary for this rare disease.Platinum-based chemotherapy can be used as an adjuvant therapy.