Predictive Significance of Changes in Haemoglobin Level Following Imatinib Treatment in Patients with Advanced Gastrointestinal Stromal Tumour.

Objective: To evaluate the predictive value of haemoglobin decrease following imatinib treatment in patients with advanced gastro- intestinal stromal tumours (GIST).

Study design: An retrospective observational study. Place and Duration of the Study: Department of Medical Oncology, Gaziantep Medical Point Private Hospital, Gaziantep, Turkiye, between July 2021 and February 2024.

Methodology: The study included 79 patients diagnosed with advanced GIST following imatinib therapy. Comprehensive clinical information, such as age, gender, tumour location, sites of metastasis, number of metastatic sites, and initial staging before treatment, was collected, and haematological parameters were measured both prior to and 1-3 months after starting imatinib. Changes in haematological parameters were analysed, and the relationship between clinical variables and both disease-free survival (DFS) and overall survival (OS) was assessed using the Kaplan-Meier method.

Results: Post-imatinib treatment, 35 patients (44.3%) experienced a decrease in haemoglobin levels. Those with reduced haemoglobin levels exhibited better progression-free survival (PFS) compared to those without a decline [43.0 months (31.5-54.5) vs. 22.0 months (14.9-29.1); p <0.001]. No significant predictive associations for PFS were identified with changes in other haematological parameters. Multivariate analysis revealed that only a decrease in haemoglobin values remained an independent predictive factor, even after adjusting for tumour localisation [2.5 (1.3-4.7); p = 0.004]. Conversely, concerning the overall survival (OS), neither the decrease in haemoglobin levels nor other haematological and clinical parameters demonstrated statistical significance following imatinib treatment.

Conclusion: Decreased haemoglobin levels following imatinib treatment is a predictive on-target toxicity in patients with advanced GIST.

Key words: GIST, Imatinib treatment, On-target toxicity, Predictive marker, Anaemia.