Relationship between Paronychia and Drug Concentrations of Epidermal Growth Factor Receptor Tyrosine Kinase...

Area of Science:

• Oncology
• Pharmacology
• Dermatology

Background:

• Non-small cell lung cancer (NSCLC) treatment often involves epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs).
• Paronychia is a common adverse event associated with EGFR TKI therapy.
• Understanding the mechanism of EGFR TKI-induced paronychia is crucial for effective management.

Purpose of the Study:

• To investigate the specific sites of paronychia occurrence in NSCLC patients treated with EGFR TKIs.
• To evaluate the relationship between EGFR TKI drug concentrations at affected sites and paronychia severity.
• To determine the drug penetration rates into finger and toe tissues.

Main Methods:

• Retrospective analysis of 55 NSCLC patients receiving EGFR TKIs.
• Grading of toxicities using Common Terminology Criteria for Adverse Events (CTCAE) v4.0.
• Quantification of drug concentrations in dried blood spots using mass spectrometry.

Main Results:

• Paronychia most frequently developed in the thumb and big toe.
• No significant correlation was observed between paronychia severity and EGFR TKI drug concentration at the affected site.
• Mean drug penetration rates from plasma to extremities were 74.1% (erlotinib), 82.2% (gefitinib), and 99.9% (afatinib).

Conclusions:

• Elevated EGFR TKI concentrations at the site of paronychia do not appear to be the primary cause.
• Patient education on avoiding local compression may be more effective than dose reduction or treatment cessation for managing paronychia.
• Further research into preventative strategies beyond drug modification is warranted.