Figure 1 PRISMA Flow Diagram.
Data extraction
Data extraction was undertaken by three reviewers (NK/RT). Key article
information was uploaded into Microsoft Excel. Data extracted included
study type, number of patients, method of biopsy including tonsillectomy
or tongue base mucosectomy, surgical technique used, number of primary
tumours detected and their location, human papillomavirus (HPV) status
and use of any additional techniques such as frozen section.