Effect of Liver Dysfunction on S-1 Therapy Induced Adverse Effects: A Retrospective Cohort Study

Area of Science:

• Oncology
• Pharmacology
• Hepatology

Background:

• Renal dysfunction often requires S-1 dose reduction.
• Decreased dihydropyrimidine dehydrogenase (DPD) activity can cause adverse events with 5-FU.
• Current guidelines use total bilirubin (T-Bil) ≤1.5x ULN for S-1 safety, but the link to liver dysfunction and dose reduction is unclear.

Purpose of the Study:

• To investigate the relationship between liver dysfunction, indicated by T-Bil levels, and S-1 dose reduction.
• To determine the clinical outcomes associated with varying T-Bil levels in patients undergoing S-1 monotherapy.

Main Methods:

• Retrospective analysis of 883 patients receiving S-1 monotherapy.
• Patients categorized into Low T-Bil (≤2.25) and High T-Bil (>2.25) groups.
• Primary outcome: variation in blood sampling results; analyzed clinical outcomes including RBC and PLT counts.

Main Results:

• 883 patients and 7,511 treatment instances analyzed; 7,245 in Low T-Bil, 266 in High T-Bil group.
• Significant correlations found between T-Bil group and RBC count, PLT count, and T-Bil level.
• High T-Bil group showed significant decreases in RBC and PLT counts compared to the Low T-Bil group.

Conclusions:

• S-1 administration in patients with liver dysfunction and elevated T-Bil may lead to thrombocytopenia.
• Monitoring T-Bil levels is crucial for managing S-1 therapy in patients with liver impairment.