Epidermal growth factor receptor gene mutation and computed tomographic findings in peripheral pulmonary adenocarcinoma

Objective: The presence of epidermal growth factor receptor (EGFR) mutations has been reported to predict the response to gefitinib in pulmonary adenocarcinoma patients. A retrospective analysis was conducted to identify the correlation between computed tomographic findings of the nodules and EGFR status. Patients and Methods: Computed tomographic findings of 38 patients with peripheral pulmonary adenocarcinoma with EGFR mutations were reviewed and compared with those of 42 peripheral pulmonary adenocarcinoma patients with wild-type EGFR. Results: Mutations were found significantly more frequently among women (28 of 45 women versus 10 of 35 men) and among nonsmokers (31 of 47 non-smokers and 7 of 33 smokers). The L858R mutation was found in 18 cases. Several types of deletion mutants in exon 19 were found in 18 cases. The nodules with EGFR mutations (2.5 +/- 1.0 cm) were significantly smaller in diameter than those in the wild-type group (3.1 +/- 1.9 cm). Ground glass opacity (GGO) was more often observed in the mutation group (28 of 38) than in the wild-type group (24 of 42), but the difference was not statistically significant. When mutations were analyzed with reference to both the tumor size and GGO ratio, patients with a tumor <= 3 cm and a GGO ratio >= 50% often had EGFR mutations, and most (10 of 12) were expressed in female patients. No male adenocarcinoma patients with a tumor larger than 4.0 cm had EGFR mutations. Conclusions: EGFR mutations were found most frequently in small peripheral adenocarcinomas with a GGO ratio >= 50%, especially among women. These factors may be useful in deciding therapeutic strategies for adenocarcinomas when resection or biopsy is not feasible.