HEAD AND NECK CANCERS
Cancers of the head and neck are generally taken to mean those of the larynx (voice box), tongue, the inside of the mouth and the pharynx (throat). These are relatively common in developing countries where smoking and alcohol abuse are problems, since they are closely associated with both smoking and alcohol use. They can be devastating cancers, since treatment often results in deformity, and if of the larynx, loss of the voice. To make matters worse, they are difficult to see and are often not picked up until they are well advanced.
Who gets head and neck cancers?
The cause of head and neck cancer has been well documented through preclinical and clinical research investigations. Approximately, 75% of all oral cancers in many countries can be attributed to excessive consumption of tobacco and alcohol, particularly when used in combination. These carcinogenic factors have been known to be dose-related and time dependent, so the higher and longer the exposure the greater the risk of developing cancer. The risk appears to drop following cessation of tobacco usage. Dentists can play a major part in preventing some of these cancers by encouraging a healthy life style, particularly in regard to tobacco usage. The overall incidence in women is much lower (1.5%) and ranks in 14th position of all cancers in that gender group.
These cancers represent five percent of all malignancies and are the fourth most common cancers in men. The larynx is the most common site, followed by the mouth and the pharynx. Head and neck cancers are usually squamous cell cancers. The increased risk of head and neck cancers among alcoholics has also been seen in a number of studies worldwide. There are also possible environmental influences such as exposure to the human papilloma viruses and the Epstein-Barr Virus (EBV), which may promote head and neck cancers. There is increasing evidence that viruses play a role in cancer of the nose. The fact that young adults and those who have never smoked, sometimes get head and neck cancers suggests that there may be a genetic predisposition. Mutations in tumor suppressor genes have been found in these people.
What are the symptoms of head and neck cancers?
There is minimal pain or discomfort during the early phases and this may account for the deferral in seeking treatment. Ignorance, poor access to appropriate health care, denial and anxiety also play important roles in the delay of diagnosis of oral cancer. Thorough inspection of the oral cavity (mouth) is a prerequisite for the early detection of oral cancer and its possible initial stages. Almost all oral malignancies are located in the soft tissues and oral cancer is often preceded for several months or even years by clinically visible whitish (leukoplakia) and/or reddish (erythroplakia) changes, so called precursor or precancerous lesions. Finger (gloved) palpation forms an essential part of the clinical examination of any mucosal lesion. Some patients complain about spontaneous bleeding, pain, a loose tooth or swelling of the mucosa. Often one hears about a "pimple" or ulcer that does not want to heal or an "irritation" in the throat. A cancer in the posterior area of the tongue may cause pain on swallowing and earache is a well-known symptom of a squamous cell carcinoma of the tongue.
Since disease that is caught early is more likely to be cured than that detected late, it is important to be aware of the early signs of one of these cancers. Cancers of the mouth can first present as non-healing ulcers, swelling, spasm of the jaw muscles and pain. Pain only in one ear is not uncommon and can be referred from other areas of the head and neck, so is an important symptom in someone who has smoked for many years.
Cancers of the nose and sinuses can result blood and mucosal discharges from the nose and persistent congestion. Because the nose and the ears are closely linked, these cancers may also sometimes first be picked up along with an ear infection and problems with balance. Large tumors of this area can affect nerves in the head and neck and cause facial pain, double vision and other neurological problems. Cancers of the upper part of the throat and soft palate are often silent and so present late symptoms. Symptoms may include sore throat, jaw spasm, pain in the ears, spitting up blood and pain and difficulty in swallowing. Cancer of the larynx is, fortunately, the only one of these cancers to show early symptoms. These are hoarseness and difficulty in breathing.
How are head and neck cancers treated?
Generally, early tumors can be treated with surgery or radiation therapy alone or in combination of both. Surgical techniques varying from a wide local excision without reconstruction for small tumors, to wide resection followed by reconstruction for larger tumors. The use of myo-cutaneous flaps and more recently microvascular free flaps permits the resection of the tumor with adequate margins and immediate one-stage reconstruction with very good functional and cosmetic results. The radial forearm free flap is most frequently used for intra-oral reconstruction, as are fibula, iliac crest or scapula free flaps for mandibular reconstruction. Advanced tumors often require chemotherapy along with surgery and radiation therapy. Modern techniques can now provide excellent control of the tumor, both at their point of origin and if they have spread. So, quality of life of those with these tumors has improved. However, overall survival has not changed much, probably because these tumors spread easily.
Radiation can be used on its own for early cancers, or as part of combined therapy with surgery and chemotherapy for advanced cancers. The advantages of radiotherapy are that it can prevent disfiguring surgery and it is effective for early tumors. The disadvantages are that it causes dental problems, swelling of the tissues of the mouth, damage to the bone of the face and jaw and cannot be used again should the cancer re-occur. The side effects are dry mouth, loss of taste and changes in skin texture.
Surgery is an effective technique on its own in early cancers and is often used in combination with radiotherapy in more advanced tumors. The advantages of surgery are that it effectively removes the cancer with few side effects in early tumors and allows a relatively quick recovery. It also allows assessment of the lymph nodes and tissue around the tumor, which is helpful in telling whether the cancer has spread. The disadvantages are potential disfigurement, loss of function and surgical complications. Chemotherapy is not widely used in head and neck cancers and its role is not well defined.
Where are we now?
The overall five-year survival rates for head and neck cancers vary according to where they are and the stage at which they are detected. Sites with a good prognosis include the lip and the glottis (part of the larynx), with survival rates of 80 to 85%. Cancers of the soft palate, base of the tongue and the nose and sinuses unfortunately generally only have survival rates of between 20 and 40%. All patients with head and neck cancers need frequent follow up since the possibility of re-occurrence is high.
Treatment of this type of cancer has advanced enormously in the past few years and the surgery is not nearly as disfiguring as it used to be. However, prevention is still the best form of treatment. Do not smoke and keep your alcohol intake at moderate levels.
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