Immunotherapy improves efficacy and safety of patients with HPV positive and negative head and neck cancer: a systematic review and meta-analysis - Galvis, Marisol Miranda; Borges, Gabriel Alvares; Oliveira, Thiago Bueno de; Toledo, Isabela Porto de; Castilho, Rogerio Moraes; Guerra, Eliete Neves Silva; Kowalski, Luiz Paulo; Squarize, Cristiane Helena (Critical reviews in oncology hematology, 2020)