[1] Natl Canc Ctr, Res Inst & Hosp, Ctr Lung Canc, Goyang, South Korea
[2] Seoul Natl Univ, Coll Med, Dept Internal Med, Div Pulm & Crit Care Med, Seoul, South Korea
[3] Hallym Univ, Chuncheon Sacred Heart Hosp, Div Pulm Allergy & Crit Care Med, Chunchon, South Korea
[4] Yeungnam Univ, Med Ctr, Reg Ctr Resp Dis, Div Pulmonol & Allergy, Daegu, South Korea
[5] Konkuk Univ, Sch Med, Med Ctr, Div Pulm & Crit Care Med,Dept Internal Med, Seoul, South Korea
[6] Sungkyunkwan Univ, Sch Med, Kangbuk Samsung Hosp, Div Pulm & Crit Care Med,Dept Med, Seoul, South Korea
[7] Soonchunhyang Univ, Cheonan Hosp, Dept Pulm Med, Cheonan Si, South Korea
[8] Seoul Natl Univ, Coll Med, Dept Internal Med, Seoul, South Korea
[9] Hallym Univ, Sch Med, Sacred Heart Hosp, Div Pulm Med,Dept Internal Med, Anyang, South Korea
[10] Univ Ulsan, Coll Med, Asan Med Ctr, Div Pulm & Crit Care Med,Dept Internal Med, Seoul, South Korea