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Updated: Jun 30, 2026
Robotic Duodenal Sleeve Resection for Gastrointestinal Stromal Tumor with Rare Exon 8 KIT Mutation Following Neoadjuvant Imatinib
Published on: April 3, 2026
Impact of Imatinib Intake Timing on Oncological Outcomes in Metastatic Gastrointestinal Stromal Tumors (GISTs): A
Kenza Bahida1,2, Mohamed El Fadli1,2, Othmane Zouiten1,2
1Medical Oncology, Mohammed VI University Hospital, Marrakech, MAR.
Background:
The time-of-day administration significantly influences treatment outcomes in various cancer settings, particularly with cytotoxic chemotherapy and immunotherapy. However, data regarding tyrosine kinase inhibitors are scarce. We aimed to investigate whether the circadian timing (morning versus evening) of imatinib administration impacts progression-free survival (PFS) in patients with metastatic gastrointestinal stromal tumors (GISTs). A secondary objective was to evaluate the impact of clinical and pathological factors, such as primary tumor site and metastatic burden, on oncological outcomes.
Methods:
We conducted a single-center retrospective study on patients with histologically confirmed metastatic GISTs, treated with first-line imatinib (400 mg/day). Patients were categorized into "Morning" (before 12 PM) or "Evening" (after 12 PM) intake groups. The primary endpoint was PFS. Survival curves were estimated using the Kaplan-Meier method and compared using the log-rank test.
Results:
Forty-four patients were included (median age 54.5 years). The primary tumor sites were mainly gastric n= 20 (45%) and small intestine n= 16 (36%). Hepatic metastases were present in 82% of cases (n= 36). Imatinib was administered in the morning for 59% of patients (n=26) and in the evening for 41% (n=18). Median PFS was 61.5 months in the Morning group versus 26.2 months in the Evening group. Despite this numerical difference, the analysis revealed no statistically significant difference (p=0.22). Gastric primary site (p=0.017) and low metastatic burden (p<0.01) were confirmed as significant favorable prognostic factors.
Conclusion:
In this cohort, no statistically significant difference in oncological outcomes was detected based on the circadian timing of Imatinib administration. While this suggests a flexible dosing schedule tailored to patient tolerance is reasonable in routine practice, larger, appropriately powered studies incorporating mutational profiling are required to definitively rule out a time-dependent therapeutic effect.
Insights
Circadian timing of imatinib administration did not significantly impact progression-free survival in metastatic gastrointestinal stromal tumors (GISTs). Gastric primary site and low metastatic burden were favorable prognostic factors for GIST patients.
Area of Science:
- Oncology
- Pharmacology
- Chronobiology
Background:
- Time-of-day drug administration affects cancer treatment outcomes, especially with chemotherapy and immunotherapy.
- Limited data exist on the impact of circadian timing for tyrosine kinase inhibitors (TKIs).
- Investigating imatinib dosing schedules in metastatic gastrointestinal stromal tumors (GISTs) is crucial.
Purpose of the Study:
- To determine if morning versus evening imatinib administration affects progression-free survival (PFS) in metastatic GIST patients.
- To assess the influence of primary tumor site and metastatic burden on GIST outcomes.
Main Methods:
- Retrospective single-center study of 44 metastatic GIST patients on first-line imatinib (400 mg/day).
- Patients grouped into "Morning" (before noon) or "Evening" (after noon) imatinib intake.
- Progression-free survival (PFS) analyzed using Kaplan-Meier and log-rank tests.
Main Results:
- Median PFS was 61.5 months (Morning) vs. 26.2 months (Evening), but this difference was not statistically significant (p=0.22).
- Gastric primary tumor site (p=0.017) and lower metastatic burden (p<0.01) were significant positive prognostic factors.
- Hepatic metastases were common (82%), and most patients had gastric or small intestine primary tumors.
Conclusions:
- Circadian timing of imatinib administration showed no statistically significant impact on oncological outcomes in this GIST cohort.
- Flexible imatinib dosing based on patient tolerance may be reasonable in clinical practice.
- Larger studies with mutational profiling are needed to confirm these findings and explore time-dependent effects.
