Haruhiko Nakamura1, Hisashi Saji2, Takuo Shinmyo2, Rie Tagaya2, Noriaki Kurimoto2, Hirotaka Koizumi3, Masayuki Takagi3. 1. Department of Chest Surgery, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan. Electronic address: h-nakamura@marianna-u.ac.jp. 2. Department of Chest Surgery, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan. 3. Department of Pathology, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan.
Abstract
BACKGROUND: The relationships between the subtypes defined by the new international histologic classification of lung adenocarcinoma (IASLC/ATS/ERS) and epidermal growth factor receptor (EGFR) mutations were studied. PATIENTS AND METHODS: We retrospectively reviewed 320 patients with lung adenocarcinoma (162 women, 158 men; mean age, 69 years) who had undergone complete resection, focusing on the new histologic subtypes and EGFR mutations. The clinical stage was IA in 196 patients, IB in 95, IIA in 10, IIB in 10, IIIA in 6, and IV in 3. RESULTS: The most prevalent subtype was papillary (35.0%), followed by acinar (29.4%), lepidic (13.1%), solid (7.2%), adenocarcinoma in situ (6.6%), minimally invasive adenocarcinoma (6.3%), micropapillary (1.6%), and invasive mucinous adenocarcinoma (1.0%). These subtypes were predictive for both postoperative disease-free and overall survival. EGFR mutations, detected in 40.6% of all cases, were most frequent in acinar (48.4%), followed by minimally invasive adenocarcinoma (45.0%) and papillary (43.8%). They were least frequent in the solid subtype (17.4%). EGFR mutation status did not affect postoperative disease-free or overall survival. CONCLUSION: The outcome after complete resection for lung adenocarcinoma was predicted by the proposed subtype classification. Because EGFR mutations were found in all subtypes, mutation analyses are essential to identify patients with postoperative relapse who would benefit from EGFR-tyrosine kinase inhibitor therapy.
BACKGROUND: The relationships between the subtypes defined by the new international histologic classification of lung adenocarcinoma (IASLC/ATS/ERS) and epidermal growth factor receptor (EGFR) mutations were studied. PATIENTS AND METHODS: We retrospectively reviewed 320 patients with lung adenocarcinoma (162 women, 158 men; mean age, 69 years) who had undergone complete resection, focusing on the new histologic subtypes and EGFR mutations. The clinical stage was IA in 196 patients, IB in 95, IIA in 10, IIB in 10, IIIA in 6, and IV in 3. RESULTS: The most prevalent subtype was papillary (35.0%), followed by acinar (29.4%), lepidic (13.1%), solid (7.2%), adenocarcinoma in situ (6.6%), minimally invasive adenocarcinoma (6.3%), micropapillary (1.6%), and invasive mucinous adenocarcinoma (1.0%). These subtypes were predictive for both postoperative disease-free and overall survival. EGFR mutations, detected in 40.6% of all cases, were most frequent in acinar (48.4%), followed by minimally invasive adenocarcinoma (45.0%) and papillary (43.8%). They were least frequent in the solid subtype (17.4%). EGFR mutation status did not affect postoperative disease-free or overall survival. CONCLUSION: The outcome after complete resection for lung adenocarcinoma was predicted by the proposed subtype classification. Because EGFR mutations were found in all subtypes, mutation analyses are essential to identify patients with postoperative relapse who would benefit from EGFR-tyrosine kinase inhibitor therapy.