[1] Hygeia Hosp, Dept Med Oncol 3, Erythrou Stavrou Str & Kifisias Ave Marousi, Athens 15123, Greece
[2] Univ Ibadan, Div Neurosurg, Dept Surg, Coll Med, 1 Queen Elizabeth Rd, Ibadan, Nigeria
[3] Ain Shams Univ, 1 Sq 1158 Sheraton Heliopolis, Cairo, Egypt
[4] Natl & Kapodistrian Univ Athens, Ippokrateio Gen Hosp Athens, Univ Dept Internal Med 2, Dept Oncol,Athens Sch Med, 114 Vas Sofias, Athens 11527, Greece
[5] Univ Zimbabwe, Coll Hlth Sci, Parirenyatwa Hosp Complex, POB A178, Harare, Zimbabwe