Author: Vanessa Ngan, Staff Writer, 2003.
There are several types of oral cancers, but over 90% are squamous cell carcinomas. Worldwide, oral cancer is one of the ten most common sites of cancer. People all over the world are affected but it appears to occur most frequently in developing countries particularly India, Pakistan and Bangladesh. In fact, in some parts of India, oral cancer accounts for more than 50% of all cancer.
Oral cancer usually occurs in people over the age of 40. It is twice as common in men as in women.
Risk factors for developing oral cancer include:
Many oral cancers are only detected when they are well advanced. Often in the early stages, the cancer is painless and may go unnoticed. This has led to a high mortality rate compared to cancers of other sites. Thus, the early recognition of signs and symptoms of oral cancer is very important. These include:
The most common sites of oral cancer are the lower lip, tongue and the floor of the mouth, although any part of the mouth may be affected. Between 30 and 80% of patients with oral cancer also have secondary lesions (metastases) in the cervical lymph nodes at presentation. At a later stage, cancer may spread to regional lymph nodes, lungs, liver or bones.
After an initial diagnosis of oral cancer, the stage of cancer will be determined. This will define the size of the tumour, how deeply the tumour has invaded tissues at the site of origin, and the extent of any invasion into surrounding organs or lymph nodes. Determining a cancer's stage is an important factor as it directs treatment planning. The 1993 American Joint Committee on Cancer TMN classification and staging of oral cancer is commonly used.
|Classification of oral cancer|
|Primary tumour||T0||No primary tumour|
|Tis||Carcinoma in situ|
|T1||Tumour 2 cm or less|
|T2||Tumour 4 cm or less|
|T3||Tumour >4 cm|
|T4||Tumour >4 cm and deep invasion into muscle, bone, deep structures|
|Lymphatic node involvement||N0||No nodes|
|N1||Single homolateral node <3 cm|
|N2||Node(s) homolateral <6 cm|
|N3||Nodes(s) >6 cm and/or bilateral|
|Tumour metastasis||M0||No metastasis|
|Staging of oral cancer|
|Stage I||T1, N0, M0|
|Stage II||T2, N0, M0|
|Stage III||T3, N0, M0
T1, T2, T3, N1, M0
|Stage IV||T4, N0, M0
Any T, N2 or N3, M0
Any T, any N, any M
Treatment of oral cancer depends on the type of cancer and the stage of the cancer. In general, diagnosis and treatment during the early stages of cancer have a much better outcome. Oral cancer squamous cell carcinoma is generally treated by surgery and/or radiation therapy. Chemotherapy may also be used, particularly in patients with confirmed metastases to other tissues and organs.
Oral health needs are addressed prior to cancer therapy. This is to minimise oral disease and post-therapeutic complications. It appears that up to 97% of patients require oral healthcare before treatment of cancer can begin. Some of the complications that may occur post-cancer treatment are radiotherapy- or chemotherapy-induced mucositis (inflamed mouth), oral ulceration, bleeding, infections, pain, xerostomia (dry mouth) and caries (holes in the teeth).
Surgery is aimed at removing the primary tumour and some of the surrounding normal tissue to make sure the cancer has been completely removed. If done during the early stages of cancer there is usually little or no post-treatment disfigurement. Surgery performed at later stages may also require reconstruction of parts of the mouth or face.
Book: Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Fourth edition. Blackwell Scientific Publications.
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