[1] Chulalongkorn Univ, King Chulalongkorn Mem Hosp, Div Med Oncol, Dept Med,Fac Med, Bangkok, Thailand
[2] Univ Texas MD Anderson Canc Ctr, Dept Thorac Oncol, Houston, TX 77030 USA
[3] Univ Texas MD Anderson Canc Ctr, Dept Head & Neck Med Oncol, Houston, TX 77030 USA
[4] Univ Texas MD Anderson Canc Ctr, Dept Biostat, Houston, TX 77030 USA
[5] Univ Texas MD Anderson Canc Ctr, Houston, TX 77030 USA
[6] Univ Texas MD Anderson Canc Ctr, Thorac Head & Neck Med Oncol, Houston, TX 77030 USA