1. Department of Oncology, Hanoi Medical University, Ton That Tung, Hanoi, Vietnam
2. Department of Oncology and Palliative care, Hanoi Medical University Hospital, Ton That Tung, Hanoi, Vietnam
3. Division of Epidemiology, Vanderbilt University Medical Center, Nashville, TN, USA
4. Department of General Medical Oncology, Quan Su Campus, Vietnam National Cancer Hospital, Quan Su, Hanoi, Vietnam