IS NEURO-ECTODERMAL DIFFERENTIATION OF EWINGS-SARCOMA OF BONE ASSOCIATED WITH AN UNFAVORABLE PROGNOSIS

Among Ewing's sarcoma (ES) of bone and related entities are tumours wi th neuro-ectodermal features that could represent a biologically disti nct type. In order to assess the prognostic significance of the variou s forms of ES, a retrospective joint study involving three cancer cent res in Europe and the U.S.A. was initiated. The material from 315 prim ary ES was reviewed by a panel of five pathologists and classified as typical ES (220 cases), atypical ES (48 cases) or ES with neuro-ectode rmal features (47 cases). Prognostic factor analysis on treatment fail ure-free survival was performed using the Cox model. It included histo pathological classification, initial patient characteristics, clinical presentation and treatment type. After multivariate analysis, in addi tion to treatment type (P < 0.001), metastases (P = 0.003) and proxima l tumour location (P = 0.006), two histopathological parameters correl ated with poor treatment failure-free survival, the presence of filigr ee pattern (P = 0.044) and dark cells (P = 0.043). We conclude that ES with neuro-ectodermal features does not appear to have a different ou tcome to the other subtypes.