OBJECTIVETo investigate the treatment methods and prognostic factors of high-risk gastrointestinal stromal tumor (GIST).

METHODSClinicopathological date and follow-up data of 108 patients with high-risk GIST from January 2002 to February 2016 treated at our department were retrospectively reviewed. The patients were divided into two groups according to whether they received adjuvant therapy after surgery. A group of patients received imatinib adjuvant therapy(adjuvant therapy group, 69 cases). Another group of patients were not treated with imatinib until they were found to have disease progression(follow-up observation group, 39 cases). The survival rate and recurrence rate were compared between two groups, and the risk factors of prognosis were analyzed by Cox regression model.

RESULTSAll the cases were followed up with a median time of 48 months(1 to 161 months). Recurrence and / or metastasis occurred in 57(52.8%) patients during follow-up. The postoperative recurrence and / or metastasis rate was 34.8%(24/69) and 84.6%(33/39) respectively in the adjuvant therapy group and the follow-up observation group, the difference was statistically significant(P=0.000). Twenty-eight(25.9%) patients died. The 1-, 3-, 5-, 10-year survival rates of the 108 patients undergoing follow-up were estimated to be 99.8%, 87.7%, 76.0% and 42.7% respectively. The 5-year survival rates were 79.3% and 72.3% in the adjuvant therapy group and the follow-up observation group, the difference was not statistically significant (P=0.648). Univariate analysis showed that mitotic count, radical degree and tumor rupture were predictive factors of survival after resection of primary high-risk GIST (all P<0.05). Multivariate analysis using Cox regression model revealed that the mitotic count (P=0.013, RR=2.400, 95%CI:1.206 to 4.779) and radical degree(P=0.003, RR=3.968, 95%CI:1.609 to 9.784) were independent prognostic factors.

CONCLUSIONComprehensive treatment of radical surgery combined with targeted therapy and close followed up can lead to better long-term survival of high-risk patients with GIST.