Background
Seventy percent of oropharyngeal squamous cell carcinomas (OPSCC) are
now associated with a positive p16 immunohistochemistry status (p16+ve
OPSCC) in Europe and the USA,1, 2 a number expected to
increase.3 p16 positive immunohistochemistry is often
used as a surrogate marker for the presence of the human papilloma virus
(HPV). HPV-related OPSCC has doubled in incidence in the United Kingdom
from 1990-2006 and again from 2006-2010.3
Compared to non-HPV associated OPSCC caused by exposure to associated
carcinogens from tobacco and alcohol, patients affected by HPV
associated disease represent a distinct population. Patients are of an
average younger age, present at an earlier stage, and occupy a median
higher socioeconomic class.4 Despite improved
survival, quality-of-life indices remain low following
treatment.5 It is therefore important to ensure that
treatments, be they surgical or non-surgical, bring acceptably low
recurrence risk whilst minimising loss of function.
Patients with p16+ve OPSCC typically present with cervical lymph node
metastasis which may be asymptomatic, and in our institution are fully
assessed clinically, radiologically and histologically with needle
biopsy (or core biopsy if required) from the cervical lymph node/s and
biopsy from the primary tumour site. Results are discussed at the
multi-disciplinary team meeting and treatment is offered that may
include primary surgery for patients whose tumours are deemed
appropriate. This consists of trans-oral surgery to the primary tumour
site (either using Trans-oral Laser Microsurgery (TLM), or Trans-Oral
Robotic Surgery(TORS)) and selective neck dissection.3Histopathological examination of neck dissection specimens then
re-stages the resected tumour and nodal disease and identifies adverse
features, which guide the decision on adjuvant non-surgical treatment.
The distribution of both clinically known and occult p16+ve OPSCC nodal
disease in each neck level is not widely reported. Evaluation of this
distribution could both reinforce the rationale for dissecting specific
neck levels and evaluate the accuracy of preoperative clinical and
radiological examination in establishing the presence and location of
nodal disease.