Introduction
Patients presenting with head and neck squamous cell carcinoma of
unknown primary (HNSCCUP) pose a diagnostic conundrum. Cancer of unknown
primary is defined as the “histological diagnosis of metastasis without
the detection of a primary tumor”1. The cited
incidence of HNSCCUP is between 2% to 5% of all head and neck squamous
cell carcinoma (SCC)2,3.
When clinical examination and imaging have failed to identify a
potential primary site, traditional further investigation of HNSCCUP
comprises examination under anaesthetic (EUA), evaluation of all
subsites of the head and neck and either targeted and/or random
biopsies. The typical biopsy sites are nasopharynx, tonsils, tongue
base, and piriform fossa, although there is considerable heterogeneity
and little high level evidence exists to support this routine4,5.
The rationale for intensively searching for the primary site is as
follows:
1. The majority of patients presenting with HNSCCUP will harbour primary
sites in the head and neck6.
2. There may be prognostic and therapeutic benefits to finding the
primary site, by being able to precisely target the primary site and
reduce the morbidity of treatment7.
This systematic review identifies the indications and practice of
oropharyngeal biopsy in HNSCCUP and focuses on the following:
1. Random versus direct biopsies
2. Management of the palatine tonsils
3. Management of the tongue base
4. Utility of surgical techniques