Oropharyngeal squamous cell carcinoma

Oropharyngeal squamous cell carcinoma (OPSCC) is the most common type of head and neck cancer in the Western world ¹.  Typically Typically it will be further categorised based on the specific anatomical location involved within the oropharynx, as this may affect prognosis and modality of treatment. 

Epidemiology:

Epidemiology and risk factors are similar to elsewhere in the aerodigestive tract. Traditionally, the the major risk factors for OPSCC are alcohol and tobacco ².

These remain important risk factors, however, in recent years there has been an increasing incidence of OPSCC caused by human papillomavirus (HPV) caused OPSCC. HPV associated OPSCC tend to occur in a younger population group, and may feature more rapid growth of disease and more pronounced locoregional lymph node involvement ². However, they also tend to respond better to chemoradiotherapy treatment and carry a better prognosis ². For this reason, OPSCC are often subcategorised into HPV associated-associated (or p16 positive) or non HPV associated-HPV-associated (or p16 negative) OPSCC.

HPV HPV positive cases of OPSCC are typically caused by HPV subtype 16, which is also the subtype associated with cervical cancer. 

Clinical presentation:

OPSCC may present differenthas a varied presentation depending on the specific anatomical site of origin. Common presenting symptoms include odynophagia and dysphagia. Because of the propensity for HPV associated-associated OPSCC to have early nodal involvement, they may also present with a neck mass. 

Pathology

As per the 2017 8^th edition American Journal Committee on Cancer (AJCC) guidelines, OPSCC are categorised into HPV/p16 positive and HPV/p16 negative, as these are different patterns of disease and carry very different prognoses. 

Location:

Common subtypes of OPSCC include tonsil, base of tongue and soft palate, however, anywhere in the oropharynx can be involved. For the purposepurposes of staging, the lingual surface of the epiglottis is excluded and considered part of the larynx, and the nasopharyngeal surface of the soft palate is considered part of the nasopharynx. 

Prognosis:Radiographic features

HPV positiveCT will typically show an asymmetric soft tissue mass with contrast enhancement within the aerodigestive tract. In more advanced disease there may be loss of normal fat planes as the tumour extends beyond its site of origin. 

Careful assessment of neck lymph nodes is essential for OPSCC tendprimary malignancies. Involved lymph nodes are usually referred to have much a much better prognosisin terms of neck lymph node levels. Features of nodal involvement include short axis diameter greater than HPV negative OPSCC10 mm, asymmetry, loss of fatty hilum. The estimated 5 year survival for HPV positive OPSCC is 90%, compared with 40% for HPV negative cases ². 

Staging:

As per the 2017 8th edition American Journal Committee on Cancer (AJCC) guidelines, OPSCC are categorised into HPV/p16 positiveSigns of nodal extra-capsular extension include loss of adjacent fat planes and HPV/p16 negative, as there are different patterns of diseaseirregular ill-define margins.

Treatment and very different prognoses. 

Treatment:

prognosis

Treatment options depend on the stage and location of the disease, as well as patient factors and suitability for different treatment options. The three primary modalities of radical treatment are surgery, radiotherapy and chemotherapy. Another systemic option that is a current area of active research is immunotherapy. 

Radiographic features:

CT

CT will typically show an asymmetric soft tissue mass

HPV positive OPSCC tend to have much a much better prognosis than HPV negative OPSCC. The estimated 5 year survival for HPV positive OPSCC is 90%, compared with contrast enhancement within the aerodigestive tract . In more advanced disease there may be loss of normal fat planes as the tumour extends beyond its site of origin40% for HPV negative cases ².