[1] Inst Nacl Enfermedades Neoplas, Pediat Oncol Dept, Lima, Peru
[2] Univ Peruana Cayetano Heredia, Post Grad Med Sch, Lima, Peru
[3] Ctr Infantile Boldrini, Radiat Oncol Dept, Sao Paulo, Brazil
[4] Univ Sao Paulo, Med Sch, Sao Paulo, Brazil
[5] Univ Fed Sao Paulo, Pediat Oncol Inst GRAACC, Pediat Oncol Dept, Sao Paulo, Brazil