Mouth, lip and oral cavity (oral cancer)
Oral cancer has the highest incidence of the head and neck cancers, and like other cancers of the upper aerodigestive tract and respiratory system, it is more common in men than in women. Fiveyear survival rates are over 80% for people with early stage, localised disease, and over 40% for whose disease has spread to the neck, but below 20% for those who have distant metastatic disease (spread to other parts of the body).
The incidence is increasing
From 1995 to 2004 the number of new diagnoses of oral cancer rose from 3696 to 4769 (six cases in every 100000 people in the UK population), an increase in age standardised incidence of 23%.
Approximately 90% of oral cancers are squamous cell carcinomas, arising from the lining of the mouth, most often the tongue and the floor of the mouth. It has been estimated that between 10 and 30% of patients with primary oral cancer develop second primary upper aerodigestive tract tumours; these patients also have higher rates of lung and bladder cancer than the general population.
Overall, the incidence of oral cancer is relatively low in England and Wales compared to many other countries. The rates are higher among people from a South Asian (Indian sub-continent) background, mirroring the high incidence in India, Pakistan and Bangladesh. Ethnic immigrants from the Indian sub-continent are more than twice as likely to die from oral cancer than natives of England and Wales.
Public awareness of oral cancer is low, probably because of its relative rarity. Those who have heard of it are more likely to be aware of the role of smoking than of other risk behaviours.
Cancer of the larynx
Cancer of the larynx (voice box) is the second most common form of head and neck cancer. It is the 14th most common cancer in males, but is much rarer among women. Survival rates are better than for oral or pharyngeal cancer, with nearly two-thirds of patients surviving for five years.
Virtually all cancer of the larynx is squamous cell carcinoma. Within the larynx, the glottis (the area containing the vocal cords) is most frequently affected. Glottic cancer has the most favourable prognosis of all forms of laryngeal cancer, as people tend to seek medical advice for chronic hoarseness, which is the most common early symptom. Other symptoms of laryngeal cancer may include pain or problems with swallowing (dysphagia). There can also be a lump in the neck, sore throat, earache, or a persistent cough.
Cancer of the pharynx
Cancer of the pharynx (throat) is less common. It occurs in three principal locations: the oropharynx, which includes the under surface of the soft palate, the base of the tongue and the tonsils, the hypopharynx (bottom part of the throat) and the nasopharynx (behind the nose). The most common site of cancer within the pharynx is the tonsil but even this is fairly rare, with just over 400 new cases per year in England. Five-year survival rates are relatively poor, at about 40% for cancer of the oropharynx and 20% for the hypopharynx..
Cancers of the oropharynx and hypopharynx are, like oral cancer and cancer of the larynx, usually squamous cell carcinomas which originate in the epithelial cells that line the throat. Cancer of the nasopharynx has a different aetiology and natural history.
Thyroid cancer, although relatively rare, is most likely to develop in women of reproductive age. It usually presents as a solitary nodule in a patient with normal thyroid hormone levels; cancer is found in about 10% of such cases. Other symptoms are uncommon, but include swollen glands in the neck (cervical lymphadenopathy), hoarseness, difficulty in breathing or swallowing, and discomfort in the neck.
The commonest type of thyroid cancer is described as "differentiated"; this accounts for 90% of cases. This is sub-divided into two forms: papillary and follicular adenocarcinoma, which account for 80% and 10% of cases, respectively. Both develop in cells that produce thyroid hormones, but papillary cancer tends to grow slowly and is usually curable. Differentiated thyroid cancers are usually treated with surgery, which can be supplemented with radioiodine ablation. Survival rates are excellent.
Five per cent of patients have medullary cancer, which is sometimes familial and can be associated with other endocrine malignancies. Again, treatment is with surgery, but this disease is more difficult to control because it tends to be more invasive and cannot be treated with radioiodine.
Finally, there are two rare types which occur in the elderly. About 1% of patients have lymphoma of the thyroid, which presents as a rapidly expanding mass and is usually diagnosed on the basis of the patient's history, together with a tissue diagnosis. Many of these patients can be cured. In contrast, the outlook is poor for the 3% of patients who have anaplastic thyroid cancer, which presents in a similar way and must be differentiated from lymphoma with a biopsy.
Other cancers of the head and neck
There are a wide range of other cancers of the head and neck which are not described above. Taken together, these are responsible for 17% of cases of head and neck cancer. All are relatively rare, the least rare being cancers of the salivary glands and cancers of the nasal cavity, middle ear and accessory sinuses. This diverse group also includes cancers and sarcomas of the facial bones, peripheral nerves, connective and soft tissues, and various glands.
Skull base cancers are included among head and neck cancers, but tumours that originate in the skull are very rare; most cancers that invade the skull originate in soft tissue. Treatment for these patients can be particularly challenging.