Objectives: To investigate the frequency of imatinib-induced pancreatic complications and determine whether these are survival prognostic factors in patients with gastrointestinal stromal tumor (GIST).
Methods: This retrospective multicenter study included patients with histopathologically diagnosed GIST treated with imatinib who underwent computed tomography (CT) within 100 days before (pretreatment CT) and 500 days after (post-treatment CT) imatinib initiation (January 2004-December 2019). Forty-eight patients (63.0 ± 12.1 years, 30 men) were included. Two blinded radiologists independently measured pancreatic volumes. Pancreatic volume on pretreatment CT was compared with that of the control (within 1 year prior to pretreatment CT) and the first two post-treatment CTs using paired t-tests. Thresholds for pancreatic hypertrophy and atrophy were defined using a log-rank test. The prognostic importance of pancreatic hypertrophy was further analyzed using multivariate Cox proportional hazard regression models.
Results: Pancreatic volume was significantly higher for the first post-treatment CT than pretreatment CT (71.5 cm3 vs. 67.4 cm3, P = .027), whereas no significant difference was observed between the pretreatment and control CTs. Optimal thresholds for pancreatic hypertrophy and atrophy were defined as an 22% increase and 30% decrease and found in 20 and three patients, respectively. Pancreatic hypertrophy was significantly associated with reduced survival [hazard ratio = 2.9 (95% confidence interval, 1.3-6.5), P = .0088]. No patients showed serum lipase elevation, nor were they suspected of having acute pancreatitis.
Conclusion: There was frequent asymptomatic pancreatic swelling in patients with GIST after imatinib treatment, and a ≥22% increase in pancreatic volume was a predictor of reduced survival.
Keywords: Drug-induced pancreatitis; Hypertrophy; Volumetry.
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