Cancer is a group of cancer-causing cells (also known as malignant cells) which infects an area and then spreads causing damage to the surrounding tissue. The oral cavity is at high risk of cancer due to the intake of various cancer-producing agents such as tobacco, alcohol and betel nuts. The floor of the mouth, tongue, lips, gingiva are some of the multiple locations where cancer can originate, most commonly the cancer of the tongue. The most common site of spread of oral cancer is the lymph nodes of the neck.
It is rare in children and young adults and increases in the age group of 45 to 50 years of age. Men are more likely to develop oral cancer.
Oral cancer causes various symptoms at an early stage, which may be similar to other diseases. Some of the common symptoms include the sore mouth, white patches, bleeding in the mouth, loose teeth and swelling in the jaw.
Diagnosing oral cancer begins with a visit to the dentist or family doctor. Based on the findings, the dentist or the doctor shall refer the patient to a head and neck surgeon who will further advise some tests. Exfoliative cytology or biopsy is a medical procedure to confirm oral cancer. Exfoliative cytology includes the use of cotton swab, brush or small wooden stick to scrape a small number of cells from the involved site. This sample is then stained with a dye and observed microscopically to observe for cancerous changes. The biopsy includes the cutting away of a portion of tissue to check for oral cancer. CT scan and MRI also help in detecting any malignant changes.
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Grading of Oral Cancer
Grading of oral cancer means finding out how many cancerous changes have taken place in the cells. This helps us know as to how much different are the cancerous cells to the healthy cells. Knowing the grade gives the doctor an idea of how quickly and how much cancer may be growing. Cancer may either be of low grade or high grade.
Low-grade cancer: They have well-differentiated and well-arranged cells. They have a good resemblance to the healthy tissue. Low-grade cancer generally spreads slowly.
High-grade cancer: They have poorly differentiated cells. They don’t look like normal cells and are arranged differently compared to normal cells. High-grade cancer generally spreads quickly.
Staging of Oral Cancer
Staging of cancer means the amount of cancer present when first diagnosed. It can also be called the extent of cancer. It is done with the help of some tests to help determine the size of cancer. It also helps us know the exact tissue where cancer has originated and also to locate where cancer has spread.
When describing the stage, doctors may use the words local, regional or distant. Local means that the cancer is only in the mouth and has not spread to other parts of the body. Regional means cancer has spread to the lymph nodes in the neck (cervical lymph nodes). Distant means in a part of the body farther from the mouth.
The most common staging system for oral cancer is the TNM system which is explained below :
T (tumor) staging
Tx – The primary lesion cannot be assessed
T0 – No evidence of primary lesion
Tis – Carcinoma in situ
T1 – Lesion 2cm or less in the greatest diameter
T2 – Lesion greater than 2cm but less than 4cm in the greatest diameter
T3– Lesion greater than 4cm in the greatest diameter
T4A – Lesion invades through the cortical bone into deep/extrinsic muscles of the tongue (genioglossus, hypoglossus, palatoglossus and styloglossus), maxillary sinus or skin of the face
T4B– Lesion invades masticatory space, pterygoid plates, or skull base and/or encases internal carotid artery
N (node) staging
Nx – The regional lymph node cannot be assessed
N0 – No regional lymph node metastasis
N1 – Metastasis to a single ipsilateral lymph node less than 3cm in greatest dimension
N2A – Metastasis to a single ipsilateral node, greater than 3cm but not more than 6cm in greatest dimension
N2B – Metastasis in multiple ipsilateral nodes none more than 6cm in greatest dimension
N2C – Metastasis in bilateral or contralateral nodes, none more than 6cm in greatest dimension
N3 – Metastasis in a lymph node more than 6cm in greatest dimension
M (metastasis) staging
Mx – Distant metastasis cannot be assessed
M0 – No distant metastasis
M1 – Distant metastasis present
Treatment for oral cancer
The treatment plan for oral cancer is based on the patient’s health, staging and grading about cancer. When deciding which treatments to offer for oral cancer, the following points will be considered:
- the size of the cancer
- the stage of the cancer
- the location of the cancer
Oral cancer is usually treated with surgery first. Surgery is followed by radiation therapy or sometimes radiation therapy and chemotherapy. Reconstruction is always needed post-surgery to repair the tissues. Reconstruction is planned at the same time as treatment.