| Background Gastrointestinal stromal tumors(GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. In the past, surgery has been the only effective treatment, but the recurrence usually happens, recurrent and/or metastatic GIST usually has no operation indication. Imatinib mesylate has proved to be the most active agent for advanced GIST, treatment with this drug has led to significant improvements in survival. There have been many reports on the study of factors influencing the prognosis of advanced GIST. However, the related study is short in China, the genetic and social factors are also different between Chinese and foreigners, thus a further study on this field is needed.Objective To study the efficacy and prognostic factors of imatinib mesylate in the treatment of Chinese patients with advanced GIST.Methods A total of 102 patients with recurrent and/or metastatic GIST were enrolled into this prospective study, from January 2002 to December 2009. Imatinib mesylate was orally administered 400mg once daily until disease progression or the occurrence of intolerable toxicity. Response rate, progression-free survival, overall survival and toxicity profile were analyzed. The clinical data were analyzed by using logistic analysis, Kaplan-Meier method, Log-rank test and Cox regression model. Results We followed up these patients until 30-Jun-2010, the median follow up time was 28 months. 3 of the 102 patients were lost in follow-up, the objective effect was evaluated in 99 patients. 8 of them(8.1%)achieved complete response(CR), 68(68.7%)achieved partial response(PR), 20(20.2%)had stable disease(SD)and 3(3.0%)had progression disease(PD). The objective response rate was 76.8%, the disease control rate was 97%. Logistic regression analysis showed that liver-metastatic GIST had a lower response rate. The median time to progression was 32 months. 57 patients had been followed up for more than 2 years, the 1-, 2-, 3-year progression-free survival rates were 84.3%, 56.1% and 46.7%, and the 1-, 2-, 3-year survival rates were 96.1%, 81.2% and 70.8%. Univariate analysis showed that City life, favourable PS, objective response and decrease in tumor density were significantly associated with better PFS, while patients with younger age, city life, favourable PS, only liver metastasis and decrease in density had better overall survival. Multivariate analyses showed that age, PS, tumor response and density change in treatment were independent prognostic factors. 97 patients were valuable for the toxicity assessment. The most common drug-related adverse events were edema(81.3%), leukopenia(46.1%), diarrhea(37.3%)and rash(35.3%), and most of them were grade 1-2 events, which were manageable and reversible.Conclusion We confirmed that many advanced GIST patients in China benefit from imatinib mesylate therapy for a prolonged time, the toxicities are mild and tolerable. Age, PS, metastatic site, remission rates and density change in treatment were important influencing factors for advanced GIST. |
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