Prognostic factors after imatinib secondary resistance: survival analysis in patients with unresectable and metastatic gastrointestinal stromal tumors
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Patients undergoing imatinib therapy for gastrointestinal stromal tumors (GISTs) show drug resistance during treatment in the late stages. The aims of this study were to determine survival after the appearance of imatinib secondary resistance (ISR) and to identify the prognostic factors.
Eligible were patients with unresectable and metastatic GISTs who were diagnosed with ISR and/or underwent treatment for ISR in our institution between 2001 and 2012. A total of 48 patients were enrolled and overall survival was retrospectively analyzed. The Cox proportional hazards model was used to identify the independent prognostic factors. Median follow-up time was 58 months.
As of the cutoff date, 41 of the 48 patients with ISR had died, of which 39 died of GISTs. The overall 1-, 3-, and 5-year survival rates of the 48 patients were 64.6, 32.8, and 20.4 %, respectively, and median survival time was 22 months. The favorable independent prognostic factors identified were long progression-free survival in first-line imatinib therapy (P = 0.04), small diameter of progressive disease (PD) (P = 0.02), and surgical resection of PD (P = 0.01).
Surgical resection of PD in selected cases could improve prognosis in ISR patients undergoing GIST treatment.
KeywordsGIST Imatinib Prognosis Secondary resistance
Best supportive care
Gastrointestinal stromal tumor
Imatinib secondary resistance
Median survival time
Platelet-derived growth factor receptor alpha
Response Evaluation Criteria in Solid Tumors
Transcatheter arterial chemoembolization
Tyrosine kinase inhibitor
This study was supported in part by a Grant-in-Aid for Scientific Research from the Japan Society for Promotion of Science (No. 24591934). The authors are grateful to Professor Kohei Akazawa, Niigata University Graduate School of Medical and Dental Sciences, for helpful advice on statistical analysis.
Compliance with ethical standards
Conflict of interest
Seiichi Hirota received lecture fees from Novartis. Tatsuo Kanda, Takashi Ishikawa, Shin-ichi Kosugi, Kyo Ueki, Tetsuya Naito, and Toshifumi Wakai have no conflict of interest.
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