Purpose: To analyze the distribution of epidermal growth factor receptor (EGFR ) mutations; characterize the clinical and imageological features of lung squamous cell carcinoma (LSCC) in a large population of patients; and assess correlations between clinical and imageological characteristics and clinical outcomes of LSCC patients harboring EGFR  mutations.
Patients and methods: Three pathologists retrospectively evaluated the morphological and immunohistochemical data of 2,322 patients with LSCC resected between February 2013 and December 2017. Data on the distribution of EGFR  mutations and the clinical and imageological characteristics of the patients were retrospectively collected. Correlations between the EGFR  mutation status and clinical outcomes were evaluated using univariate and multivariate analyses.
Results: EGFR  mutations were found in 3.4% of patients with LSCC and predominantly in female and non-smoking patients. Tumor lesions in patients with EGFR -positive mutations were more irregularly shaped than those in patients with EGFR -negative mutations (P  = 0.045). In non-smoking patients with LSCC, the proportion of marked spiculation was significantly higher in the EGFR -positive group than in the EGFR -negative group (P  = 0.043). No significant difference in recurrence-free survival was noted between LSCC patients harboring EGFR -positive and those harboring EGFR -negative mutations. No difference in metastases was observed between the EGFR -positive and EGFR -negative cohorts.
Conclusion: Female gender, non-smoking habit, irregularly shaped tumor, and marked spiculation might predict the presence of EGFR  mutations in LSCC. The administration of tyrosine kinase inhibitors to patients with LSCC after screening for EGFR  mutations based on their clinical and imageological features would likely result in a population with a greater sensitivity to afatinib.
Keywords: EGFR  mutation, lung squamous cell carcinoma, imageological feature, recurrence-free survival