Prognostic factors in malignant gastrointestinal stromal tumors

Gastrointestinal stromal tumors are a heterogeneous group of mesenchymal ne oplasms of the gastrointestinal tract in which routine histopathological ev aluation fails to reveal definitive evidence of differentiation. Given the heterogeneity in clinical presentation and the frequent morphological overl ap, the biological behavior of these neoplasms is difficult to predict. We have evalauated, by Cox Proportional Hazards Regression Analysis, the clini copathological features of 51 malignant gastrointestinal stromal tumors to identify predictors of survival. In the univariate analysis, survival inver sely correlated with size, number of mitoses, and patient's age. In the mul tivariate analysis, only the degree of necrosis and phenotypic differentiat ion toward smooth muscle were found to be indicators of poor prognosis. Bas ed on these results, a simple classification scheme for gastrointestinal st romal tumors is proposed. This classification appears to have great prognos tic value for these tumors, and may be useful in guiding therapeutic manage ment.