Cancer and Other Growths of the Mouth
Oral cancers develop in 30,000 Americans and cause 8,000 deaths each year, mostly in people over age 40. This represents about 2.5 per cent of cancer cases and 1.5 per cent of all cancer-related deaths - a high rate considering the small size of the mouth in relation to the rest of the body. Along with cancers of the lungs and skin, cancers of the mouth are more preventable than most other cancers.
Noncancerous (benign) and cancerous (malignant) growths can originate in any type of tissue in and around the mouth, including bone, muscle, and nerve. Cancers that originate in the lining of the mouth or surface tissues are called carcinomas; cancers that originate in the deeper tissues are called sarcomas. Rarely, cancers found in the mouth region have spread there from other parts of the body - most commonly the lung, breast, and prostate.
Screening for oral cancer should be an integral part of medical and dental examinations because early detection is critical. Cancers less than a half inch across usually can be cured easily. Unfortunately, most oral cancers aren’t diagnosed until they’ve spread to the lymph nodes of the jaw and neck. Because of delayed detection, 25 per cent of oral cancers are fatal.
People who use alcohol and tobacco are at greatest risk of developing oral cancer. The combination of alcohol and tobacco is more likely to cause cancer than either of them alone. About two-thirds of oral cancers occur in men, but increased tobacco use among women over the past few decades is gradually closing the gender gap.
Cigarette smoking is more likely to cause oral cancer than cigar or pipe smoking. A brown, flat, freckle-like area (smoker’s patch) may develop at the site where a cigarette or pipe is habitually held in the lips. Only a biopsy (removal of a tissue specimen and examination under a microscope) can determine whether the patch is cancerous.
Repeated irritation from the sharp edges of broken teeth, fillings, or dental prostheses (such as crowns and bridges) may add some risk for oral cancer. People who have had one oral cancer are at increased risk of developing another cancer.
Symptoms and Diagnosis
Oral cancers occur most commonly on the sides of the tongue, the floor of the mouth, and the back portion of the roof of the mouth (soft palate). Cancers on the tongue and floor of the mouth are usually squamous cell carcinomas. Kaposi’s sarcoma is a cancer of the blood vessels near the skin. It occurs commonly in the mouth-usually on the roof of the mouth (palate)-of people with AIDS.
In those who use chewing tobacco and snuff, the insides of the cheeks and lips are common sites of cancer. These cancers are often slow-growing verrucous (warty) carcinomas.
Melanoma, a cancer that usually occurs on the skin, occurs less commonly in the mouth. An area in the mouth that has recently become brown or darkly discolored may be a melanoma and should be examined by a doctor or dentist. A melanoma must be distinguished from normal pigmented areas in the mouth, which occur in some families and are particularly common among dark-skinned and Mediterranean people.
Tongue cancer is invariably painless in the early stage and is usually detected during a routine dental examination.
Cancer typically appears on the sides of the tongue. It almost never develops on the top of the tongue except in someone who has had untreated syphilis for many years. Squamous cell carcinomas of the tongue often look like open sores and tend to grow into the underlying structures.
A red area in the mouth (erythroplakia) is a predictor of cancer. Anyone with a red area on the sides of the tongue should see a doctor or dentist.
Floor of the Mouth
Cancer of the floor of the mouth is invariably painless in the early stage and is usually detected during a routine dental examination. As with cancer of the tongue, cancer of the floor of the mouth is usually squamous cell carcinoma, which looks like open sores and tends to grow into underlying structures.
Anyone with a red area (erythroplakia) on the floor of the mouth should see a doctor or dentist because it may indicate cancer.
Cancer of the soft palate can be squamous cell carcinoma or cancer that begins in the small salivary glands in the soft palate. Squamous cell carcinoma often looks like an ulcer. Cancer beginning in the small salivary glands commonly appears as a small swelling.
Lining of the Mouth
When the moist inner lining of the mouth (oral mucosa) is irritated for a long period, a flat white spot that does not rub off (leukoplakia) may develop. The injured spot appears white because it’s a thickened layer of keratin - the same material that covers the outermost part of the skin and normally is less abundant in the lining of the mouth. Unlike other white areas that develop in the mouth - usually from the buildup of food, bacteria, or fungi - leukoplakia can’t be wiped off. Most leukoplakia results from the mouth’s normal protective response against further injury. But in the process of forming this protective covering, some cells may become cancerous.
By contrast; a red area in the mouth (erythroplakia) results from a thinning of the lining of the mouth. The area appears red because the underlying capillaries are more visible. Erythroplakia is a much more ominous predictor of cancer than leukoplakia. A person with any red area in the mouth should see a doctor or dentist.
An ulcer is a hole that forms in the lining of the mouth when the top layer of cells breaks down, and the underlying tissue shows through. An ulcer appears white because of the dead cells inside the hole. Mouth ulcers frequently result from tissue injury or irritation - for instance, when the inside of the cheek is accidentally bitten or scraped. Other causes are canker sores and irritating substances, such as an aspirin, held against the gums. Noncancerous ulcers are invariably painful. An ulcer that does not hurt and lasts more than 10 days may be precancerous or cancerous and should be examined by a doctor or dentist.
A person who chews tobacco or uses snuff may develop white, ridged bumps on the insides of the cheeks. These bumps can develop into verrucous carcinoma.
A distinct lump or raised area on the gums (gingiva) is not a cause for alarm. If such a lump is not caused by a periodontal abscess or abscessed tooth, it may be a noncancerous growth caused by irritation. Noncancerous growths are relatively common and, if necessary, can be easily removed by surgery. In 10 to 40 per cent of people, the noncancerous growths recur because the irritant remains. If the irritant is a poorly fitting denture, it should be adjusted or replaced.
The lips - most commonly the lower lip - are subject to sun damage (actinic cheilosis), which makes them cracked and red, white, or mixed red and white. A doctor or dentist may perform a biopsy to determine whether these rough spots on the lips are cancerous. Cancer on the outside of the lip is more common in sunny climates. Cancers of the lip and other parts of the mouth often feel rock hard and stick to the underlying tissue, while most noncancerous lumps in these areas are freely movable. Abnormalities in the upper lip are less common than those on the lower lip but are more likely to be cancerous and require medical attention. A person who chews tobacco or uses snuff may develop white, ridged bumps on the inside of the lips. These bumps can develop into verrucous carcinoma.
Salivary gland tumors can be cancerous or non-cancerous. They may occur in any of the three pairs of major salivary glands: parotid gland (on the side of the face in front of the ear), submandibular gland (under the side of the jaw), or sub-lingual gland (on the floor of the mouth in front of the tongue). Tumors can also occur in the minor salivary glands, which are scattered through - out most of the lining of the mouth. The early growth of salivary gland tumors may or may not be painful. Cancerous tumors tend to grow fast and feel hard.
Many kinds of noncancerous cysts cause jaw pain and swelling. Often, they are next to an impacted wisdom tooth and, even though they are not cancerous, they can destroy considerable areas of the jawbone as they expand. Certain types of cysts are more likely to recur. Odontomas are noncancerous overgrowths of tooth-forming cells that look like small, misshapen extra teeth. Because they may take the place of normal teeth or get in the way of normal teeth coming in, they are often surgically removed.
Jaw cancer often causes pain and a numb or unusual sensation, somewhat like the feeling of a mouth anesthetic wearing off. X-rays can not always distinguish jaw cancers from cysts, noncancerous bone growths, or cancers that have spread from elsewhere in the body. However, X-rays usually show the irregular borders of jaw cancer and may show that the cancer has eaten away the roots of nearby teeth. Typically, a biopsy (removal of a tissue specimen and examination under a microscope) is needed to confirm a diagnosis of jaw cancer.
Prevention and Treatment
Staying out of the sun reduces the risk of lip cancer. Avoiding excessive alcohol and tobacco use can prevent most oral cancers. Smoothing rough edges from broken teeth or restorations is another preventive measure. Some evidence indicates that antioxidant vitamins, such as vitamins C and E, and beta-carotene may provide added protection, but further study is needed. If sun damage covers a large area of the lip, a lip shave in which all of the outer surface is removed, either by surgery or with a laser, may prevent a progression to cancer.
The success of treatment for oral and lip cancers depends largely on how far the cancer has progressed. Oral cancers rarely spread to distant sites in the body but tend to invade the head and neck. If the entire cancer and the surrounding normal tissue is removed before the cancer has spread to the lymph nodes, the cure rate is high. If the cancer has spread to the lymph nodes, cure is much less likely. During surgery, the nodes under and behind the jaw and along the neck as well as the cancer in the mouth are removed. Surgery for mouth cancers can be disfiguring and psychologically traumatic.
A person with mouth or throat cancer may receive radiation therapy and surgery or just radiation therapy. Radiation therapy often destroys the salivary glands and leaves the person's mouth dry, which can lead to cavities and other dental problems. Because jawbones exposed to radiation don't heal well, dental problems are treated before radiation is administered. Any teeth likely to become problems are removed, and time is allowed for healing. Good dental 'hygiene is important for people who have had radiation therapy for oral cancer. Such hygiene includes regular examinations and thorough home care, including daily home fluoride applications. If the person eventually has a tooth pulled, hyperbaric oxygen therapy may help the jaw heal better.
Chemotherapy has a limited therapeutic benefit for mouth cancers. The mainstays of treatment are surgery and radiation therapy.
Cancer of the Nasopharynx
Cancer of the upper part of the pharynx (nasopharynx) may occur in children and young adults. Although rare in North America, it's one of the most common cancers in the Orient. It's also more common in Chinese who have immigrated to North America than in other Americans and slightly less common in American born Chinese than in their immigrant parents. The Epstein-Barr virus, which causes infectious mononucleosis, also plays a role in the development of nasopharyngeal cancer.
Often, the first symptom is persistent blockage of the nose or eustachian tubes. If a eustachian tube is blocked, fluid may accumulate in the middle ear. A person may have a discharge of pus and blood from the nose and nosebleeds. Rarely, part of the face becomes paralyzed. The cancer may spread to lymph nodes in the neck.
A doctor diagnoses the cancer by performing a biopsy (removal of a small tissue sample for examination under a microscope) of the tumor. The tumor is treated with radiation therapy. If the tumor is large or persists, surgery may be needed. Overall, 35 percent of the people survive for at least 5 years after diagnosis.
Cancer of the Tonsil
Cancer of the tonsil occurs predominantly in men and is strongly linked to smoking and alcohol consumption.
Usually, a sore throat is the first symptom. Pain often radiates to the ear on the same side as the affected tonsil. Sometimes, however, a lump in the neck resulting from the cancer's spread to a lymph node (metastasis) may be noticed before any other symptoms. A doctor diagnoses the cancer by performing a biopsy (removal of a tissue sample for examination under a microscope) of the tonsil.
Because smoking and alcohol consumption may also be linked to other cancers, laryngoscopy (examination of the larynx), bronchoscopy (examination of the bronchial tubes), and esophagoscopy (examination of the esophagus) also are performed. Treatment includes both radiation therapy and surgery. Surgery may involve removal of the tumor, lymph nodes in the neck, and part of the jaw. About 50 percent of the people survive for at least 5 years after diagnosis.
Cancer of the Larynx
Cancer of the larynx, the most common cancer of the head and neck except for skin cancer, is more common in men and is linked to cigarette smoking and alcohol consumption.
This cancer commonly originates on the vocal cords, causing hoarseness. A person who has been hoarse for more than 2 weeks should seek medical attention. Cancer in other parts of the larynx causes pain and difficulty in swallowing. Sometimes, however, a lump in the neck resulting from the cancer's spread to a lymph node (metastasis) may be noticed before any other symptoms.
To make the diagnosis, a doctor looks at the larynx through a laryngoscope (a tube used for direct viewing of the larynx) and performs a biopsy (removal of a tissue sample for examination under a microscope) of the tissue suspected to be cancer. Then the cancer is classified by stage, from I to IV based on how extensively it has spread.
Treatment depends on the precise location of the cancer within the larynx. For cancer in an early stage, surgery or radiation therapy is the usual treatment. When the vocal cords are affected, radiation therapy is often preferred because it usually preserves the normal voice.
For cancer in an advanced stage, the usual treatment is surgery, which can include removing part or all of the larynx (partial or total laryngectomy), often followed by radiation therapy. When treated, 90 percent of people who have cancer in stage I survive for at least 5 years, compared with 25 percent of those who have cancer in stage IV
Totally removing the vocal cords leaves a person with no voice. A new voice can be created by one of three methods: esophageal speech, a tracheoesophageal fistula, or an electrolarynx. For esophageal speech, a person is taught to take air into the esophagus while inhaling and gradually expel the air to produce a sound. A tracheoesophageal fistula is a one-way valve surgically inserted between the windpipe (trachea) and the esophagus. The valve forces air into the esophagus while the person inhales, producing a sound.
If the valve malfunctions, fluids and food may accidentally enter the windpipe. The electrolarynx is a device that acts as a sound source when it's held against the neck, The sounds produced by all three methods are converted into speech as in normal speech by using the mouth, nose, teeth, tongue, and lips. However, the voice produced by these methods sounds artificial and is much weaker than the normal voice.
Dr. Akhtaruzzuman, Md
The author is a medical practioner in New York, USA.
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