Abstract
INTRODUCTION: In addition to the two common epidermal growth factor receptor (EGFR) mutations, there are many uncommon mutations. Due to the high number of uncommon types, as well as the rarity of patients, there is lack of information regarding patient demographics, especially age distribution and smoking status. Against this background, we conducted an analysis to clarify the background of patients with uncommon EGFR mutations, especially considering their age distribution and smoking status. MATERIALS AND METHODS: We retrospectively reviewed the medical records of non-small cell lung cancer (NSCLC) patients diagnosed in a multicenter clinical practice from 2002 to 2023. Patients included all cases of non-advanced and advanced NSCLC with uncommon EGFR mutations. RESULT: Information on 158 patients with uncommon EGFR mutation was collected. Median age was 72 years, with the age distribution showing that most patients were in their 70s. There was a significant difference between the proportion of patients aged up to 59 years and the proportion aged 75 years or older. In 88 patients with a smoking habit history, a significant correlation was found between smoking index and age. Among non-smokers, there was a peak between ages 70 and 74, which was older than the peak among smokers. CONCLUSIONS: Even in elderly patients and NSCLC patients with a history of smoking, although it is unclear whether EGFR mutation is common or uncommon, EGFR gene testing should be performed considering the possibility of these patients being EGFR-positive.