[1] Yonsei Univ, Coll Med, Div Med Oncol, Dept Internal Med,Yonsei Canc Ctr, Seoul 120752, South Korea
[2] Yonsei Univ, Coll Med, Div Pulmonol, Dept Internal Med,Yonsei Canc Ctr, Seoul 120752, South Korea
[3] Yonsei Univ, Coll Med, Dept Thorac & Cardiovasc Surg, Seoul 120752, South Korea
[4] Gachon Univ, Gil Hosp, Inchon, South Korea