Studies that evaluated FDG-PET/CT to detect distant metastases and second primary cancers in at least 10 patients with head and neck cancer at the time of tumour staging were eligible for inclusion. Studies had to use histopathologic analysis and/or clinical and imaging follow-up as the reference standard and report sufficient data to construct a 2x2 table of test performance at the patient level. Studies that focused exclusively on secondary cancers or of patients with M0 stage carcinoma by conventional imaging were excluded.
Included studies assessed the initial staging and/or restaging of cancer. Prospective and retrospective studies were included. Studies were conducted in Germany, Korea, Singapore, Taiwan and USA. PET/CT images were analysed quantitatively and/or qualitatively. Patient age, where reported, ranged from 16 to 94 years. The proportion of men ranged from 72% to 93%. The reference standard consisted of histopathologic analyses or clinical and imaging follow-up for between six and 24 months.
Two reviewers independently selected studies for inclusion. Disagreements were resolved through consensus.