[1] Univ San Carlos, Hosp Clin, Dept Med Oncol, Madrid, Spain
[2] Univ San Carlos, Hosp Clin, Neurosurg, Madrid, Spain
[3] Hosp Univ La Paz, Neurosurg, Madrid, Spain
[4] Univ San Carlos, Hosp Clin, Pathol, Madrid, Spain
[5] Hosp Maria Auxiliadora, Dept Med Oncol, Lima, Peru