OBJECTIVETo evaluate and compare the value of Modified NIH criteria and AFIP criteria for the risk classification of gastrointestinal stromal tumors (GIST).

METHODSClinicopathological and follow-up data of 539 patients diagnosed as primary GIST with or without irregular tyrosine kinase inhibitors in the Nanfang Hospital(n=143), Sun Yat-sen University Cancer Center (n=138), Guangdong Provincial People's Hospital (n=102) and Wuhan Union Hospital (n=156) from January 2012 to December 2015 were retrospectively analyzed. Recurrence risks of these 539 patients were classified by the modified NIH criteria and AFIP criteria. Overall survival and tumor-free survival of patients with different risks were compared by Log-rank test and the accuracy of the two criteria in predicting postoperative recurrence was compared by receiver operating characteristic(ROC) curves.

RESULTSOf 539 GIST patients, 283 were male and 256 were female; the age was (56.5±12.5) years old; tumors of 390 cases (72.4%) located in the stomach; tumor diameter of 178 cases (33.0%) was more than 5 cm; nuclear division number of 164 cases(30.4%) was more than 5/50 high magnification. The mean follow-up time was (37.5±13.6) months. According to the modified NIH criteria, the mean overall survival time of patients with very low, low, intermediate, and high risk was 52.0, 57.0, 56.9 and 53.6 months respectively (P=0.002), and the mean tumor-free survival time was 56.0, 58.1, 58.2 and 51.2 months respectively (P=0.000). According to the AFIP criteria, the mean overall survival time of patients with very low, low, intermediate, and high risk was 54.1, 57.8, 55.5 and 52.0 months respectively(P=0.015), and the mean tumor-free survival time was 57.3, 56.6, 54.9 and 50.4 months respectively(P=0.000). While predicting the risk of postoperative recurrence, the ROC curve of AFIP criteria has a larger area under the curve compared to the curve of the modified NIH criteria(0.689 vs 0.641, P<0.05).

CONCLUSIONCompared with the modified NIH criteria, AFIP criteria predicts the risk postoperative recurrence more accurately in GIST patients.