Oral cancer is the 11th most common cancer in the world, accounting for an estimated 300,000 new cases and 145,000 deaths in 2012 and 702,000 prevalent cases over a period of five years (old and new cases).
Oral cancers include cancers of the mucosal lip, tongue, gum, floor of the mouth, palate, and mouth, corresponding to the International Classification of Diseases, 10th revision [ICD-10], codes C00, C02, C03, C04, C05, and C06, respectively.
Two-thirds of the global incidence of oral cancer occurs in low- and middle- income countries (LMICs); half of those cases are in South Asia. India alone accounts for one-fifth of all oral cancer cases and one-fourth of all oral cancer deaths.
Tobacco use, in any form, and excessive alcohol use are the major risk factors for oral cancer. With dietary deficiencies, these factors cause more than 90 percent of oral cancers.
Preventing tobacco and alcohol use and increasing the consumption of fruits and vegetables can potentially prevent the vast majority of oral cancers.
When primary prevention fails, early detection through screening and relatively inexpensive treatment can avert most deaths.
However, oral cancer continues to be a major cancer in India, East Asia, Eastern Europe, and parts of South America, where organized prevention and early detection efforts are lacking.NCI figures:
ORAL CANCER: MANAGEMENT AND TREATMENT
For mouth cancer, the aim of surgery is to remove any affected tissue while minimising damage to the rest of the mouth.
Radiotherapy uses doses of radiation to kill cancerous cells. In mouth cancer, it's usually used after surgery to prevent the cancer returning. In throat cancer, it's often the first treatment to be given, in combination with medication (chemoradiotherapy).
The treatment is usually given every day over the course of six weeks, depending on the size of the cancer and how far it's spread.
Internal radiotherapy, also known as brachytherapy, can be used to treat early-stage cancers of the tongue. It involves placing radioactive implants directly into the tumour while you're under a general anaesthetic.
The implants will be left in for one to eight days, during which time the cancer cells will receive a much higher dose of radiation than the rest of your mouth.
Chemotherapy is sometimes used in combination with radiotherapy when the cancer is widespread, or if it's thought there's a significant risk of the cancer returning.
Chemotherapy uses powerful cancer-killing medicines, which damage the DNA of the cancerous cells, interrupting their ability to reproduce.
The medicines used in chemotherapy can sometimes damage healthy tissue, as well as the cancerous tissue according to NHS figures.
Targeted drug therapy
Targeted drugs treat mouth cancer by altering specific aspects of cancer cells that fuel their growth. Cetuximab (Erbitux) is one targeted therapy approved for treating head and neck cancers in certain situations.”
Cetuximab is a new type of medication, known as a biologic or antibody, which is sometimes used instead of standard chemotherapy to treat mouth cancer.
It doesn't cause all of the side effects of standard chemotherapy and is normally used in combination with radiotherapy.
Cetuximab targets proteins on the surface of cancer cells, known as epidermal growth factor receptors. These receptors help the cancer grow – by targeting them, cetuximab prevents the cancer spreading.
The National Institute for Health and Care Excellence (NICE) ruled that cetuximab didn't represent a cost effective treatment in most cases and has recommended it only be used in people who:
are in a good state of health and likely to make a good recovery if treated
are unable to have chemotherapy for medical reasons – for example, because they have kidney disease or are pregnant”
Newer targeted cancer therapies
Therapies being developed to target specific molecules and pathways in carcinogenesis are shown in the table below:
Photodynamic therapy (PDT)
Photodynamic therapy (PDT) may be recommended if there are mouth lesions that are close to turning into cancer, or the cancer is just on the surface of the mouth lining at a very early stage. However, its cure rate hasn't yet been compared with conventional treatment.
PDT can also be used to temporarily control cancer where it's been decided that further conventional treatment won't provide a cure or benefit.
PDT involves taking a medicine that makes all your skin and other tissues sensitive to the effects of light. The cancerous tissue becomes even more sensitive.
After receiving the medicine, light is shone on to the cancer using lasers. This destroys the surface of the cancer and some mouth lining next to it.
TREATMENT ACCORDING TO CANCER STAGE
Treatment of Early-Stage Oral Cancer (Stages I and II)
Surgery and radiotherapy are widely used for the treatment of early oral cancer, either as single modalities or in combination. The choice of modality depends on the location of the tumor, cosmetic and functional outcomes, age of the patient, associated illnesses, patient’s preference, and the availability of expertise.
Most early-stage oral cancers can be locally excised or treated with radiotherapy, with no or minimal functional and physical morbidity. Elective neck dissection to remove lymph nodes may be considered in selected cases, such as patients with stage I tongue cancer and stage II cancers at other oral sites, who may be at high risk of microscopic but not clinically evident involvement of the neck nodes (N0).
External beam radiotherapy and brachytherapy—using radioactive sources implanted in the tumor—either alone or in combination, is an alternative to surgery for early-stage oral cancers. Excellent outcomes have been demonstrated following brachytherapy alone or in combination with external beam radiotherapy for small tumors. Deep infiltrative cancers have a high propensity to spread to regional lymph nodes; therefore, brachytherapy alone, which does not treat regional nodes adequately, is not recommended. Newer techniques, such as three dimensional conformal radiotherapy and intensity modulated radiotherapy, can minimize the side effects of radiotherapy by delivering the radiation dose to the tumor more precisely and accurately while avoiding healthy surrounding tissues. However, these treatments require advanced equipment and are more expensive than conventional radiotherapy.
Treatment of Locally Advanced Tumors of the Oral Cavity (Stages III and IV)
Locally advanced tumors are aggressive, and locoregional treatment failure rates are high. A combined modality approach integrating surgery, radiotherapy with or without chemotherapy, and planned and executed by a multidisciplinary team is always preferred. Appropriate importance should be given to factors such as functional and cosmetic outcomes and the available expertise. Surgery followed by postoperative radiotherapy is the preferred modality for patients with deep infiltrative tumors and those with bone infiltration. Postoperative concurrent chemo-radiation has been found to be superior to radiotherapy alone in those with surgical margins showing cancerous changes indicating incomplete excision of the tumor. The use of chemotherapy prior to surgery may eliminate the need to remove the mandible—a major benefit—although it does not confer a survival benefit.
Primary radiotherapy, with or without chemotherapy, is a reasonable option for locally advanced tumors without bone involvement, especially for patients who have inoperable disease, who are medically unfit for surgery, or who are likely to have unacceptable functional and cosmetic outcomes with surgery. Incorporating chemotherapy with surgery or radiotherapy is useful in younger patients who are in good general condition, increasing survival by about 5 percentage points at five years.”