Objective: To evaluate the efficacy and safety of imatinib mesylate in the treatment of patients as preoperative supplement, or used alone for unresectable and(or) metastatic gastrointestinal stromal tumor (GIST).
Methods: A total of 30 cases with advanced GIST were proved pathologically. Among them, CD117 was detected positive in 29 patients; 2 patients received imatinib mesylate before operation and 28 patients with unresectable and(or) metastatic GIST received oral imatinib mesylate daily at dose of 200-600 mg. Three patients were lost in follow-up and the objective effect was evaluated in 25 patients.
Results: Fifteen of 25 patients (60.0%) achieved partial response (PR); 5 (20.0%) had stable disease (SD) and 5 (20.0%) had progression disease (PD). Median time to progression (mTTP) was more than 13 months during which most experienced benefit. Twenty-two patients had been followed-up more then 1 year. The 1-year survival rate was 86.4%. The overall median survival has not been obtained to date. Twenty-seven patients were valuable for the toxicity assessment according to the WHO standard. The main toxicity included grade I-II edema of periorbital area and lower limb in 85.2% (23/27) patients, leukopenia was present in 40.7% (11/27) and intratumoral bleeding in 7.4% (2/27). Other toxicities included mild fatigue (29.6%), abdominal pain (14.8%), efflorescence (11.1%), nausea and vomiting (18.5%).
Conclusion: As an inhibitor of tyrosine kinase, imatinib mesylate is generally well tolerated and has been proved to be effective and safe during prolonged treatment of patients with advanced gastrointestinal stromal tumors.