[1] Seoul Natl Univ Hosp, Div Pulm & Crit Care Med, Dept Internal Med, Seoul 03080, South Korea
[2] Seoul Natl Univ, Bundang Hosp, Med Res Collaborating Ctr, Seongnam, South Korea
[3] Seoul Natl Univ, Bundang Hosp, Div Pulm & Crit Care Med, Dept Internal Med,Coll Med, Seongnam, South Korea
[4] Catholic Kwandong Univ, Med Oncol, Coll Med, Int St Marys Hosp, Incheon, South Korea
[5] Seoul Natl Univ, Bundang Hosp, Coll Med, Div Hematol & Med Oncol,Dept Internal Med, Seongnam, South Korea