Effect of epidermal growth factor receptor gene mutations on adverse events of gefitinib in patients with non-small cell lung cancer

Abstract

7096 Background: The objective of this study is to elucidate clinical features and adverse events of patients with or without epidermal growth factor receptor gene (EGFR) mutations during gefitinib treatment. Methods: Among 108 patients with non-small cell lung cancer who received gefitinib in our hospital between November 2000 and October 2004, EGFR mutations were searched in exons 18 to 21 by direct sequence method in 26 patients. We retrospectively reviewed the clinical records and compared EGFR mutation status with the various clinical factors and adverse events during gefitinib treatment. Results: Of all 26 patients, EGFR mutations (exon 18, 0; exon 19 in-frame deletion, 6; exon 20, 0; exon 21 L858R, 5), were detected in 11 patients and not detected in 15 patients. Patients characteristics with vs. without EGFR mutations were as follows: male/female, 36%/64% vs. 73%/27%; adenocarcinoma/others, 100%/0% vs. 73%/27%; median age, 64 (range; 40–77) vs. 68 (range; 33–77); ECOG performance status 0–1/2–4, 64%/34%, vs. 67%/33%; and smokers/never smokers, 18%/82% vs. 87%/13% (p=0.001), respectively. Response rates with and without EGFR mutations were 64% (7/11 patients) and 20% (3/15 patients), respectively. The median survival time after the initiation of gefitinib treatment was 10.8 months, with a median follow-up time of 33.4 months. Grade 3 or more toxicities by the National Cancer Institute-Common Toxicity Criteria with vs. without EGFR mutations included hepatic toxicity (0% vs. 6.7%), skin rash (18.2% vs. 0%), and diarrhea (0% vs. 0%), respectively. Pulmonary toxicity/interstitial lung disease developed in two (13.3%) patients without EGFR mutations, but did not in patients with EGFR mutations, although there was no statistical significance. Conclusions: We could not find any relationships between EGFR mutation status and adverse events during gefitinib treatment in this analysis. No significant financial relationships to disclose.