Ewing's sarcoma: value of tumor necrosis as a predictive factor

Forty cases of Ewing's sarcoma filed at the Uruguayan Committee for the Study of Bone Tumors, in the 1956-1979 period, were reviewed in order to determine the prognostic importance of several clinical and histological factors. Necrosis showed a strong association with survival (regression coefficient of -0.59). In fact, those cases with slight necrosis presented an actuarial survival of 48 per cent at a five-year period, contrasting with no survivors in the group with marked necrosis. Multivariate techniques (Multiple Linear Regression and Analysis of Variance) were employed to identify possible subsets of Ewing's sarcoma. In particular, the combination of longer delay (time between the appearance of the first symptom and histologic diagnosis) and slight necrosis as well as treatment with multidrug chemotherapy and slight necrosis resulted in rather prolonged survivals. This suggests interactions between necrosis and delay, and necrosis and treatment. The strong predictive value of tumor necrosis is probably related with rapidly growing Ewing's sarcoma.