[1] Catholic Univ Korea, Yeouido St Marys Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med,Coll Med, 62 Yeouido Dong, Seoul 150713, South Korea
[2] Yonsei Univ, Dept Appl Stat, Seoul, South Korea
[3] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Pulm & Crit Care Med, Seoul, South Korea
[4] Daegu Catholic Univ, Dept Internal Med, Sch Med, Daegu, South Korea
[5] Catholic Univ Korea, Coll Med, Dept Thorac & Cardiovasc Surg, St Vincents Hosp, Suwon, South Korea
[6] Seoul Natl Univ, Coll Med, Dept Thorac & Cardiovasc Surg, Bundang Hosp, Seoul, South Korea
[7] Chungnam Natl Univ, Div Pulmonol, Dept Internal Med, Daejeon, South Korea
[8] Sungkyunkwan Univ, Samsung Med Ctr, Dept Med, Seoul, South Korea
[9] Pusan Natl Univ Hosp, Dept Cardiothorac Surg, Pusan, South Korea
[10] Chonnam Natl Univ, Hwasun Hosp, Dept Pathol, Hwasun, South Korea
[11] Natl Canc Ctr, Proton Therapy Ctr, Res Inst & Hosp, Goyang, South Korea
[12] Natl Canc Ctr, Canc Registrat & Stat Branch, Goyang, South Korea
[13] Chonnam Natl Univ, Hwasun Hosp, Dept Internal Med, Hwasun, South Korea
[14] Catholic Univ Korea, Seoul St Marys Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med,Coll Med, Seoul, South Korea
[15] Catholic Univ Korea, Coll Med, Postech Catholic Biomed Engn Inst, Seoul, South Korea