A multicenter long‐term study of imatinib treatment for Japanese patients with unresectable or recurrent gastrointestinal stromal tumors

Background and Objectives This multicenter study, which was conducted in northern Kanto, Japan, aimed to assess the efficacy of imatinib mesylate against advanced or recurrent gastrointestinal stromal tumors (GIST). Methods The clinicopathological data of 234 GIST patients who were treated at one of the 11 participating hospitals from 2001–2011 were retrospectively reviewed. Imatinib was administered as a first-line therapy in cases involving unresectable disease or postoperative recurrence (41 cases). The median follow-up period was 4.0 years. Results After a median follow-up period of 4.0 years, the patients treated with imatinib (n = 41) exhibited 1-, 3-, and 5-year overall survival (OS) rates of 92.3%, 74.9%, and 53.8%, respectively. In univariate and multivariate analyses, imatinib dose reduction and achieving a complete or partial response were found to be associated with increased OS. Conclusions Long-term imatinib treatment is recommended for patients with non-progressive disease. If patients experience significant toxicities, temporary dose reduction might be useful. J. Surg. Oncol. 2014; 110:942–946. © 2014 Wiley Periodicals, Inc.