[1] Catholic Univ Korea, Coll Med, Dept Internal Med, Div Pulm & Crit Care Med,Incheon St Marys Hosp, Seoul, South Korea
[2] Univ Ulsan, Asan Med Ctr, Dept Pulmonol & Crit Care Med, Coll Med, Seoul, South Korea
[3] Univ Ulsan, Asan Med Ctr, Dept Oncol, Coll Med, Seoul, South Korea
[4] Chungnam Natl Univ, Dept Internal Med, Div Pulmonol, Daejeon, South Korea
[5] Sungkyunkwan Univ, Samsung Med Ctr, Dept Radiat Oncol, Sch Med, Seoul, South Korea
[6] Chonnam Natl Univ, Hwasun Hosp, Lung & Esophageal Canc Clin, Hwasun, South Korea
[7] Chonnam Natl Univ, Dept Internal Med, Med Sch, Gwangju, South Korea
[8] Yonsei Univ, Yonsei Canc Ctr, Dept Radiat Oncol, Coll Med, Seoul, South Korea
[9] Univ Ulsan, Asan Med Ctr, Dept Thorac & Cardiovasc Surg, Coll Med, Seoul, South Korea
[10] Hallym Univ, Coll Med, Dept Internal Med, Div Hematol Oncol,Sacred Heart Hosp, Anyang, South Korea
[11] Catholic Univ Korea, Coll Med, Dept Internal Med, Div Pulm Crit Care & Sleep Med,Eunpyeong St Marys, 1021 Tongil Ro, Seoul 03312, South Korea
[12] Hallym Univ, Coll Med, Dept Internal Med, Div Pulm Allergy & Crit Care Med,Sacred Heart Hos, 22 Gwanpyeong Ro 170 Beon Gil, Anyang 14068, South Korea