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.