Data extraction
Three reviewers (EQ, JEC, and LB) independently extracted data into a Microsoft Excel spreadsheet. Data extracted included the year of publication, country, study design, number of participants, inclusion/exclusion criteria, sample characteristics, type of cancer, patient’s functionality, chemotherapy agent, dose average, number of cycles, concomitant radiotherapy exposure, audiometric measurements, kind of ototoxicity, type of intervention, comparator, time of follow-up, and efficacy and safety outcomes. To ensure consistency, extracted data were compared between reviewers, and disagreements were discussed until a consensus was reached.