Methods
Search strategy
Bibliographic databases Pubmed, Medline and Embase search engines were
searched to identify studies from inception to October 2021. Search
terms used included “cancer of unknown primary” AND “tonsillectomy”
OR “tongue base mucosectomy” OR “lingual tonsillectomy”, “unknown
primary tumour AND squamous cell carcinoma of head and neck”,
“oropharyngeal cancer AND biopsy”.
Inclusion and exclusion criteria
All primary human studies were included regardless of study type.
Exclusion criteria included individual case reports, non-original
studies, studies with non-extractable data, or including large
proportions of non-squamous cell carcinoma patients.
Within the literature, variability exists as to when individual authors’
make a HNSCCUP diagnosis 8. The heterogeneity results
from the extent of the preceding workup prior to diagnosis. No
meaningful adjustments could be made to standardise the workup and so no
exclusions were made on this basis.
Study selection
The Preferred Reporting Items for Systematic Reviews and Meta-analyses
(PRISMA) guidelines were followed9 Titles and
abstracts were independently screened by two reviewers (NK/RT).
Disagreements were resolved by discussion with the senior authors (SL).