1. Medical Oncology Section, The Oncology Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
2. Clinical Oncology Department, Faculty of Medicine, Menoufia University, Shibin El Kom, Egypt
3. Department of Oncology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
4. The Oncology Center, King Fahad Specialist Hospital, Dammam, Saudi Arabia
5. Clinical Oncology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
6. Department of Medicine, Security Forces Hospital, Riyadh, Saudi Arabia
7. Department of Bio-statics, Epidemiology & Scientific Computing, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia