What is Cancer?
The organs and tissues of the body are made up of tiny building blocks called cells. Cancer is a disease of these cells. Although cells in different parts of the body may look and work differently, most repair and reproduce themselves in the same way. Normally, this division of cells takes place in an orderly and controlled manner. If, for some reason, the process gets out of control, the cells will continue to divide, developing into a lump which is called a tumour. Tumours can be either benign or malignant.
Benign tumors are not cancer. They can usually be removed, and in most cases, they don't grow back. Most important, the cells in benign tumors do not invade other tissues and do not spread to other parts of the body. Benign tumors usually are not a threat to life.
Malignant tumors are cancer. They can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or the lymphatic system. This is how cancer spreads and forms secondary tumors in other parts of the body. The spread of cancer is called metastasis.
When oral cancer spreads, it usually travels through the lymphatic system. Cancer cells that enter the lymphatic system are carried along by lymph, an almost colorless, watery fluid containing cells that help the body fight infection and disease. Along the lymphatic channels are groups of small, bean-shaped organs called lymph nodes (sometimes called lymph glands). Oral cancer that spreads usually travels to the lymph nodes in the neck. It can also spread to other parts of the body. Cancer that spreads is the same disease and has the same name as the original (primary) cancer.
In a benign tumour the cells do not spread to other parts of the body and so are not cancerous. If they continue to grow at the original site, however, they may cause a problem by pressing on the surrounding organs.
A malignant tumour consists of cancer cells which have the ability to spread beyond the original site. If the tumour is left untreated, it may invade and destroy surrounding tissue. Sometimes cells break away from the original (primary) cancer and spread to other organs in the body through the bloodstream or lymphatic system. When these cells reach a new site they may go on dividing and form a new tumour, often referred to as a secondary or a metastasis.
Doctors can tell whether a tumour is benign or malignant by examining a small sample of cells under a microscope. This is called a biopsy.
It is important to realise that cancer is not a single disease with a single cause and a single type of treatment. There are more than 200 different kinds of cancer, each with its own name and treatment.
What are cancers of the head and neck?
Cancer can occur in any of the tissues or organs in the head and neck.
Cancers of the oral cavity. These can develop on the lips or in the mouth itself. Cancer can occur inside the mouth in the tongue, the hard palate (the roof of the mouth), the gums, the floor of the mouth (under the tongue) and the inner lining of the lips and cheeks (sometimes referred to as the buccal mucosa).
Oropharyngeal cancer. This develops in the oropharynx, the part of the throat that sits directly behind the mouth . It includes the soft palate (the soft part of the roof of the mouth), the base of the tongue (the part you cannot see), the side walls of the throat (where the tonsils are found) and the back wall of the throat (also called the posterior pharyngeal wall).
Laryngeal cancer : Cancer of the larynx occurs mainly in middle-aged and older people but can occur in younger people who started smoking at an early age. It is more common in men than in women. As with other cancers, cancer of the larynx is not infectious and so cannot be passed on to other people.
Cancer of the nose. Cancers can develop in the skin of the nostril and the lining of the nose. The highest part of the throat, which lies behind the nose, is called the nasopharynx. A particular type of cancer called nasopharyngeal carcinoma can develop here. Alongside the nose, in the bones of the face, lie air spaces known as the sinuses (or paranasal sinuses). Cancers can develop in the linings of these areas too.
Cancer of the ear. Cancers of the ear are uncommon and most develop in the skin of the ear. They can develop in the structures deep inside the ear but these cancers are very rare.