[Efficacy and safety of adjuvant post-surgical therapy with imatinib in gastrointestinal stromal tumor patients with high risk of recurrence: interim analysis from a multicenter prospective clinical trial].

OBJECTIVE: To evaluate the efficacy and safety of postoperative adjuvant chemotherapy with imatinib in gastrointestinal stromal tumor(GIST) patients who had high risk of recurrence.

METHODS: A prospective, open-label, multi-center trial conducted in sixteen teaching hospitals in China was carried out. The criteria of the enrolled patients included age more than 18 years old, CD117 positive GIST, tumor size more than 5 cm, pathological mitosis counts more than 5/50 HPF, and treatment beginning within 4 weeks after complete resection and with imatinib (400 mg, once a day) for at least 12 months. The 1, 3 year recurrence rates, disease free survival, overall survival rate and quality of life were evaluated.

RESULTS: From Aug. 16th 2004 to Sep. 13th 2005, there were totally 74 patients screened and 57 patients (34 men, 23 women) enrolled in the imatinib treatment group. The primary tumors were located in the stomach in 50.9%, the small intestine in 38.6% and the colorectum in 10.5% of the cases. All the patients received radical resection. Until the cut-off date of interim analysis, there was no evidence of tumor relapse or metastasis in all patients and no death was reported either. Among the 57 enrolled patients with intention to treat(ITT), twelve patients finished the protocol (per protocol, PP). The disease free survival was (268.3 +/-120.2) d in ITT analysis, and (396.7+/-38.2) d in the PP analysis. The incidence of adverse effect was 44.4% . The score in quality of life showed no statistically significant difference between the baseline visit and the follow-up visits.

CONCLUSION: Imatinib is a promising postoperative adjuvant chemotherapy in GISTs patients with high risk of recurrence, and the adverse effects are receivable.