Clinicopathologic, Molecular Diagnostic Study And Prognostic Factors Of Patients With Primary Spinal Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumors

Objective: Primary spinal Ewing sarcoma(ES)/peripheral primitive neuroectodermal tumors(p PNETs)are extremely rare malignant tumor.Because most of the studies about primary spinal ES/p PNETs are small sample clinical studies and case reports,there is still a lack of large-scale case studies,so it is difficult to have a comprehensive and profound understanding of primary spinal ES/p PNETs.The purpose of this study was to illustrate the clinicopathologic,immunohistochemical and ultrastructural features of primary spinal ES/p PNETs,and to discuss prognostic factors by survival analysis.It is important for guiding clinical treatment and improving patient prognosis.Methods: The clinical data of 40 patients,who had been surgically treated from January 2003 to December 2018 and in whom immunohistochemical staining results had confirmed the diagnosis of primary spinal ES/p PNETs,were retrospectively analyzed.A fluorescence in situ hybridization(FISH)analysis was performed in 6 cases.Progression-free survival(PFS)and overall survival(OS)were estimated by the Kaplan–Meier method to identify potential prognostic factors.Factors of p values ? 0.1 in the Log-rank tests were subjected to multivariate analysis by Cox regression analysis.Results: Forty(100%)patients were positive for CD99 and 26(65%)patients were positive for Friend Leukemia Virus Integration 1(FLI-1).EWS/FLI1 translocation was detected in 6 cases.The population comprised 24 men and 16 women with a mean age of 21.9(range,1–45)years.The median PFS was 14 months.The 1-,2-,and 5-year PFS rates were 57.7%,30.4%,and 9.5%,respectively.The median OS was 25 months.The 1-,2-,and 5-year OS rates were 74.8%,50.7%,and 12.2%,respectively.The univariate analysis suggested that postoperative Frankel score,adjuvant chemotherapy,adjuvant radiotherapy,and extent of resection were potential prognostic factors for PFS and OS.However,after these factors were subjected to multivariate analyses,only adjuvant radiotherapy and extent of resection remained as independent prognostic factors.Conclusions: Primary spinal ES/p PNETs are extremely rare and have a poor prognosis.The clinical manifestations of patients included acute onset,short duration,and rapid progression.CD99 combined with FLI-1 is of great value in the diagnosis of ES/p PNETs.The golden standard for diagnosing ES/p PNET is the identification of the tumor type-specific fusion genes EWSR1/FLI-1.Surgical treatment is the cornerstone of therapy for primary intracranial ES/p PNETs.The aim of surgery is to relieve symptoms,control local recurrence,achieve a sufficient volume reduction for further oncological management,and prolong patient survival.Gross total resection combined with adjuvant radiotherapy and chemotherapy can improve the quality of life and prolong survival time.