Imatinib treatment in metastatic or inoperable gastrointestinal stromal tumours (GIST) has shifted the paradigm of treatment of this disease. Successful clinical trials of imatinib led to rapid regulatory approval and, in England and Wales, National Institute for Health and Clinical Excellence (NICE) guidance on use of this technology. NICE recommend detailed audit of their guidelines in clinical practice. This audit reflects that guidance and was designed to document the use of imatinib in routine clinical practice.
Methods: We conducted a retrospective audit of patients with GIST treated with imatinib from 1 February 2002 to 31 March 2007. Information gathered included patient demographics, disease characteristics and details of treatment administered, treatment response, toxicities and follow-up data. The primary objective was to record disease control rate (DCR), defined as a lack of progression on computed tomography at three months. Secondary end points of this audit were progression-free and overall survival. These were compared with published clinical trial results.
Results: Thirty-six consecutive patients with a diagnosis of GIST treated with imatinib were identified. Median age of patients was 70.1 years. At the time of analysis, patients have been followed up for a median of 41.6 months. In total, patients were treated for a median of 15.8 months. Treatment was generally well tolerated with a small percentage of patients experiencing grade 3/4 toxicities. Disease control was observed in 30 patients (DCR, 83.3%, 95% CI 67.2–93.6, intention to treat analysis). The median progression free survival (PFS) in this cohort was 23.7 months (95% CI 12.9–34.4); while the median overall survival was 39.7 months (95% CI 22.8–56.5).
Conclusion: Our data demonstrated that the treatment of unselected GIST patients within the NICE guidance compares favourably to previously published data of randomized registration studies of imatinib. Of note, the median age of this cohort is some ten years older than that reported in the trials. Imatinib was well tolerated with acceptable treatment-related adverse events.