Oropharyngeal Tumours

Oropharyngeal tumours are a group of often uncommon (and sometimes very rare) tumours. Squamous cell carcinoma (SCC) is the most commonly encountered pathology (it occurs in about 90% of oropharyngeal tumours²) but other diseases include:³

• Salivary gland cancers
• Adenocarcinoma
• Lymphoma
• Sarcomas
• Melanomas

Due to their location, the tumours or the treatment modalities may have a profound impact on the most basic functions of breathing and eating. There may also be important practical, social and psychological sequelae e.g. impairment of speech, gastrostomy-tube dependence and the possible disfigurement.⁴ Furthermore, the strong association with certain types of life-style (these cancers are associated with heavy tobacco and alcohol consumption) means that some of these patients will find the burden of treatment tough to bear and will need a range of specialist support in their management.

Early presentation tends to be associated with good outcomes. However late presentations are common; treatment in these cases can be particularly demanding and the outlook may be very bleak.

The oropharynx includes the:

• Base of tongue
• Inferior surface of the soft palate and uvula
• Interior and posterior tonsillar pillars
• Glossotonsillar sulci
• Pharyngeal tonsils
• Lateral and posterior pharyngeal walls

The borders of the oropharynx include:

• Anteriorly - the circumvallate papillae
• Superiorly - the plane of the superior surface of the soft palate
• Inferiorly - the plane of the hyoid bone inferiorly
• Laterally/posteriorly - the pharyngeal constrictors
• Laterally - the medial aspect of the mandible

Although it is helpful to have a sense of where a tumour may lie and its relationship with neighbouring structures, in the reality of primary care it is not important to be so precise about the anatomy and large tumours may extend beyond this space.

• There are an estimated 130,000 new cases a year worldwide.⁵
• Mouth and oropharyngeal cancers account for 1.7% of diagnosed cancers in the UK.²
• Men are involved about 3 or 4 times as frequently as women.⁶
• There are geographical variations in prevalence; in India, this group of cancers accounts for 50% of all cancer cases.³

Risk factors

• Heavy smoking, heavy alcohol consumption (the two act synergistically) and poor dentition are the principle risk factors in western countries.⁷ Chewing tobacco and similar substances (e.g. betel quid, common in parts of Asia and among some immigrant groups in the UK) is also a risk factor.
• Several carcinogens, occupational exposures and nutritional deficiencies (e.g. zinc and vitamin A) may predispose individuals.⁸
• The human papilloma virus is thought to be linked to oropharyngeal cancer. It is found in a third of affected patients.²
• Other associations have been with excessive sunlight exposure (although this is more associated with melanoma of the lip than oropharyngeal tumours) and poor mouth cleanliness.

History

• Sore throat
• Bleeding causing haemoptysis
• Dysphagia
• Odynophagia (pain on swallowing)
• Halitosis
• Pain referred to the ear
• Changes in the voice
• Trismus suggests involvement of the pterygoid musculature
• Presentation may be the lump of a lymph node metastasis
• Weight loss

You may find our related records on Problems in the Mouth, Mouth Ulcers and Salivary Gland Disorders helpful.

Examination

It is important to do a full head and neck examination (inspection and palpation) including the mouth.⁹ A mass may be visible. Palpate for nodes. Lymph node metastases generally occur in the upper jugular chain, although they can "skip" to lower levels and spread. Bilateral metastases are more common with tongue base and soft palate lesions, especially with midline lesions.

Biopsy is the only way to establish the diagnosis. A fine needle aspiration or biopsy may be an alternative for a neck mass and lesions that are harder to reach may require endoscopy. Imaging (CT and MRI) studies should focus on identifying spread: invasion through the pharyngeal constrictors, bony involvement of the pterygoid plates or mandible, invasion of the parapharyngeal space or carotid artery, involvement of the prevertebral fascia and extension into the larynx. Chest X ray will identify pulmonary metastases and a liver function test may raise suspicions of abdominal metastases (in which case, a CT of the abdomen is warranted).

This is as for the oral cavity. Most tumours are irregular in shape and hence the term diameter refers to the maximum diameter.

• Stage I - early disease.
• Stage II - locally advanced disease.
• Stage III - tumour present in lymph nodes.
• Stage IV - metastatic disease.

Patients may also said to be in an unknown stage.

Referral^1,2

Refer urgently (ENT or maxillofacial unit) if there is/are:

• Hoarseness persisting for more than 6 weeks.
• Unexplained mouth ulcers lasting more than 3 weeks.
• Unexplained swollen areas that persist for more than 3 weeks.
• Painful, swollen or bleeding red or white patches.
• Prolonged, unexplained throat ache.
• Unexplained neck mass that has changed over a 3-6 week period or unexplained lymphadenopathy.
• Unexplained unilateral pain of the face/neck associated with ear ache that persists for over a month.
• Loose tooth/teeth for over 3 weeks (referral to the dentist in the first instance is appropriate).
• Unilateral nasal obstruction, particularly when associated with a purulent discharge.
• Cranial neuropathies (seek neurological review too).
• Orbital masses (seek ophthalmology review too).

An urgent chest X ray is also warranted in individuals who have an unexplained change in the quality of their voice (hoarse, husky or quiet) for more than 3 weeks, particularly in smokers and heavy drinkers.

Make a non-urgent referral for non-painful, non-swollen red or white plaques that do not bleed but that are persistent and unexplained. This may be erythroplakia or leukoplakia, both of which can be pre-malignant.

Hospital management

Management will be by a multidisciplinary team which may involve a combination of ENT surgeons, oncologists, restorative dentists and others such as specialist nurses, speech and language therapists and dieticians. The treatment modality depends on the type of oropharyngeal cancer, the extent and grade of the disease and the impact of the disease and treatment on the upper aerodigestive tract. The optimum balance between the various treatments needs to be ascertained.^10,11 An overview of the treatment options is provided here but decisions made in specialist units depend on the individual circumstances.

Surgical treatment

This is common for early stage disease where there are superficial lesions that do not merit a full course of radiation. It may also complement radiotherapy and can involve a radial neck dissection if there is known lymph node involvement or suspicion of spread. Surgery is necessary if the primary tumour involves the mandible and resectable recurrent disease. Extensive surgery of the base of the tongue significantly alters the patient's ability to swallow. Reconstruction of the tongue with preservation of the larynx requires surgical techniques that maintain tongue mobility and suspend the larynx and neotongue to prevent aspiration.

Radiotherapy and chemotherapy

Radiotherapy will be limited to those patients with stage I disease. Chemotherapy may be helpful for patients with stage II disease and possibly later stages too depending on individual cases. It will also be used in recurrent cases where surgery and radiotherapy have already been tried. Treatment of oropharyngeal SCC increasingly moves towards chemotherapy and radiotherapy rather than surgery. Tumours are often poorly differentiated and respond well to radiotherapy. Chemotherapy may also function as a radiation sensitiser. In recent studies, the local control rate has achieved 90% even in stage IV disease, although overall survival has not improved over more traditional surgery and radiation therapy.¹² There may be less problems with swallowing after chemotherapy than with surgery and radiotherapy.¹³

Combination treatments

A combination of chemo- and radiotherapy may be used but it is a tough regime and not suitable for all patients. Chemoradiation ± surgery is more effective than radiotherapy ± surgery for all the cancers combined but there is still a paucity of data concerning the outcomes of treatment in site-specific and stage-specific oropharyngeal cancers.⁵

Palliative care

This will need to be considered in the terminal stages of the disease. See our record on Palliative Care.

Psychological support⁴

Whilst mortality is at the forefront of many peoples' minds when considering outcome, the quality of life experienced by the individual prior to terminal disease needs to be considered. Important factors contributing to the quality of life include stage of illness, gastrostomy-tube dependence, complication, recurrence and treatment modality.¹⁴ These issues need to be addressed openly with the person and their family in order to help them come to terms with the disease.

Surgical resection or contracture after radiotherapy of the soft palate may result in velopharyngeal insufficiency (VPI). This causes nasal regurgitation of liquids and solids and hypernasal speech. Surgical augmentation of the soft palate can be performed or a palatal obturation may be used:

• With surgical augmentation of the palate, the balance between reducing VPI and causing obstructive sleep apnoea is difficult.
• A palatal obturator requires cleaning and is not permanent but patients are able to remove them during sleep. For patients who have had the base of the tongue resected, an inferiorly directed palatal obturator assists in achieving contact at the tongue base that is necessary for the projection of food posteriorly during the oral and pharyngeal phases of swallowing.

Other complications may include hypernasal speech, dysphagia¹⁵ and middle ear effusion (from scarring of the eustachian tube or loss of function of tensor and/or levator palatini muscles).³

Recurrence¹⁶

The risk of recurrence is strongly dependent on the site and stage of the original disease. About 25% of recurrences are asymptomatic and therefore these patients should benefit from close oncological follow-up in the first 3 years with liberal use of imaging ± endoscopic exploration under anaesthesia. 60% of patients have recurrence by 2 years and 80% by 3 years.

Mortality

The outlook for these patients has improved over the past couple of decades. The survival depends heavily on the stage of the disease at presentation but the overall survival rate at 5 years is about 55% and 41% at 10 years. When considering all the different forms of orolaryngeal cancers together, the 2 year survival rate is:¹

• Stage I - 89.7%
• Stage II - 71.8%
• Stage III - 57.6%
• Stage IV - 48.6%
• Unknown staging - 69.8%

However, these should be interpreted with caution for any single case with such a varied group of conditions.

There are no screening programmes for oropharyngeal cancer in the UK. Promotion of healthy lifestyles is the mainstay of prevention for this and many other diseases. High risk patients should be encouraged to visit the dentist regularly.