OBJECTIVETo evaluate the implication of Fletcher and Miettinen biologic potential grading criteria in native localized gastrointestinal stromal tumors (GISTs).

METHODSTwo hundred and twenty localized GISTs with complete clinicopathologic and follow-up data were evaluated for their biologic potential by Fletcher and Miettinen grading criteria. The implication of the two grading criteria were compared by survival analysis.

RESULTSEvaluated by Fletcher grading criteria, the overall and disease-free survival rate of high risk GISTs was lower than that of very-low, low and intermediate GISTs; while the overall and disease-free survival rate of very-low, low and intermediate risk GISTs had no statistical diffence. In the high risk GISTs, the overall and disease-free survival rate of small intestinal and rectal GISTs was lower than that of gastric GISTs; while in the intermediate risk GISTs, the disease-free survival rate of small intestinal GISTs was lower than that of gastric GISTs. Evaluated by Miettinen grading criteria, the overall and disease-free survival rate of high risk GISTs was lower than that of very-low, low and intermediate GISTs; while the overall and disease-free survival rate of very-low, low and intermediate risk GISTs had no statistical difference. In the risk subgroup of GISTs, the overall and disease-free survival rate of gastric, small intestinal and rectal GISTs had no statistical difference.

CONCLUSIONSFletcher grading criteria is simple and easy to use; while Miettinen grading criteria for evaluating biological potential by anatomic site is more critical and has important reference implication for the selection of high risk patients for targeted adjuvant treatment.