Oral Cavity Cancer

What is Oral Cavity Cancer?

Head and neck cancers account for about 5 percent of all tumours. Of these, oral cavity cancer accounts for about 30 percent of head and neck cancers. The most common site for oral cavity cancer is the tongue, followed by buccal mucous membrane.

The oral cavity begins at the lips and extends back to the front of the tonsils, and the bottom of the soft palate, including the floor of the mouth, the anterior two thirds of the tongue, and the retro molar trigone (the area behind the last lower molar tooth).


Oral Cancer Symptoms

Oral Cavity Cancer

The most common presenting symptom is a non-healing ulcer, often painful but sometimes may not be painful on either side of the tongue, buccal mucous membrane or palate. Bleeding can occur but is less common. As this lesion increases in size, different symptoms may occur including:

  • Increased local pain
  • Pain or swallowing
  • Pain referred to the ear
  • Change in speech
  • Difficulty swallowing
  • Painless lump in the neck

All treated cases, regardless of the treatment modality, experience significant difficulties with speech and swallowing.


Causes of Oral Cancer

Tobacco and alcohol are the major risk factors for oral cavity cancer.

The prevalence of oral cavity cancers appears to be increasing and there is emerging evidence linking this increased incidence to exposure of Human Papilloma Virus (HPV).

In countries where beetle nut chewing is common, such as India, it too is an important contributing factor.


Clinical Examination

Meticulous examination of the oral cavity, with good illumination, is mandatory. It is important to assess tongue movement, to examine the floor of the mouth, the buccal mucosa and the retromolar trigone in turn. Any suspicious area should be palpated with a gloved finger. It is important to examine the whole upper aerodigestive tract, including the larynx, pharynx and hypopharynx, because in between 5-10 percent of cases with oral cavity cancer, there will be a synchronous second caner of the upper aerodigestive tract.

Examination of the neck particularly levels 1, 2 and 3 is critical to see if there are any lymph node metastases.

Imaging

If you identify a lesion in the oral cavity and you cannot palpate metastatic disease in the neck, the patient should be referred to a specialist in Otolaryngology Head and Neck Surgery as a matter of some priority. The ENT surgeon will not only complete meticulous examination of all of the upper aerodigestive tract, but will organise appropriate imaging which may be a high resolution spiral CT scan, a MRI scan, or a PET scan to assess the tumour extent and distant spread.

Tumour staging

Tumours less than 2cm in size are called T1. A tumour greater than 2cm but less than 4cm is called T2.

Tumours greater than 4cm are called T3 and any tumour that is deeply invading bone, skin or other areas of the head and neck is labeled as T4.


Lymph Node Staging

If a lymph node is involved, this is labeled as N1, if there is one lymph node less than 3cm on the side of the tumour. Lymph node involvement is labeled N2 if a single lymph node is greater than 3cm but less than 6cm on the side of the tumour or if there is a lymph node on the opposite side of the neck, or, if there are more than one lymph node present.

If the lymph node in the neck is greater than 6cm then it is labeled N3.


Treatment of Oral Cancer

The three major treatment modalities are surgery, radiotherapy and chemotherapy.

Patients with oral cavity cancer are appropriately assessed in a multidisciplinary head and Neck Clinic, after an initial assessment, imaging and biopsy by an Otolaryngology Head and Neck Surgeon.

If surgical treatment is required, particularly in advanced cases, specialist reconstruction needs to be undertaken.

Overall survival rates, after appropriate treatment for cancer of the oral cavity, is appropriately 70 percent for patients who have stage 1 or stage II disease. This figure drops to about 50 percent five-year survival for stage III disease and further declines to approximately 35 percent survival five-year survival for Stage IV disease.

Follow up

After treatment of an oral cavity cancer, patients needs to remain under careful follow up for life. Initially the patient is seen monthly, then at three and six monthly intervals. The follow up visits tend to alternate between the treating surgeon and a multidisciplinary Head and Neck Clinic.


Critical Points

  • Early diagnosis leads to early treatment, which leads to less radical treatment and better survival.
  • Do not assume that any lesion in the oral cavity, exophytic or ulcerative, is post-traumatic or benign until such time as this is biopsy-proven.
  • Meticulous examination of the whole upper aerodigestive tract is mandatory as 5-10 percent of people with oral cavity cancer have a synchronous secondary primary.
  • Lifelong follow up is essential as an additional 5-10 percent of these patients will develop a second metachronous primary.
  • We must remain cogent of the major risk factors, specifically smoking and drinking, and do all we can to educate and help our patient’s minimise their exposure to these risk factors.
  • We must be aware of the emerging evidence linking oral cavity cancer to Human Papilloma Virus exposure.