ORAL CANCER

oral cancer definition:

 

a malignant neoplasm on the lip or in the mouth that occurs at an average age of 60, with a frequency eight times higher in men than in women. Predisposing factors are alcoholism, heavy use of tobacco, poor oral hygiene, ill-fitting dentures, syphilis, Plummer-Vinson syndrome, betel nut chewing, and, in lip cancer, pipe smoking and overexposure to sun and wind. Premalignant leukoplakia or erythroplasia or a painless nonhealing ulcer may be the first sign of oral cancer; localized pain usually occurs later, but lymph nodes may be involved early in the course. Diagnostic measures include digital examination, biopsy, exfoliative cytology, x-ray film of the mandible, and chest films to detect metastatic lung lesions. Almost all oral tumors are epidermoid carcinomas. Adenocarcinomas occur occasionally, whereas sarcomas and metastatic lesions from other sites are rare. Small primary lesions may be treated by excision or irradiation, and more extensive oral tumors may be treated by surgery, with removal of involved lymph nodes and preoperative or postoperative radiotherapy. Among chemotherapeutic agents administered are cisplatin, methotrexate, 5-fluorouracil, bleomycin, and adriamycin. Postoperative nursing care involves maintenance of airway patency, relieving pain, promoting adequate nutrition, and health teaching regarding follow-up care and psychosocial adjustment if body image has been affected.

Mosby's Medical Dictionary, 8th edition.

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cancer (kan´sur),

n a malignant neoplasm. The term is sometimes incorrectly used to include any neoplasm, whether benign or malignant.
Carcinoma and
sarcoma are more specific terms.

cancer, oral,

n malignancies indicative of unchecked cell growth that are mainly found in and around the oropharynx, gingiva, floor of the oral cavity, lower lip, and base of the tongue.

Mosby's Dental Dictionary, 2nd edition. 

 

Types

Oral cancer is classified according to two criteria:
1. The cancer location. According to this criterion, there are two types of oral cancer:

1) Oral cavity cancer - the cancer that starts in the mouth, which includes the tongue, lining of the cheeks, gums and teeth, upper or lower jaw, the hard palate (the mouth’s roof), the mouth’s floor (the area beneath the tongue), and salivary glands.
2) Oropharyngeal cancer - the cancer that starts in the oropharynx, which includes the soft palates (the back of the mouth), the base of the tongue, uvula, and tonsils (one of two small masses of lymphoid tissue located on either side of the throat). Around two-thirds of the oral cancers are found in the mouth, while one-third are found in the pharynx.

2. The cells where the cancer starts. There are two types of oral cancer:

1. Squamous cell carcinoma: This is a type of cancer that starts in the flat cells (called squamous cells) that cover the surface of the oral cavity and orophadynx. Squamous cells carcinoma represents more then 90 percent of all oral cancers. In its early stages, this cancer is confined to the lining layer of the cells and is called carcinoma in situ, but when it extends beyond the lining, it is called invasive squamous cell carcinoma.
A variant of squamous cell carcinoma is verrucous carcinoma. This is a low-grade cancer that rarely metastasis, and has a good prognosis. This type of oral cancer is common among patients that chew tobacco or use snuff (a fine -ground tobacco which is sniffed or snorted). It represents less than 5 percent of all diagnosed oral cancers.
2. Minor salivary gland cancer: This is a type of cancer which starts within the salivary glands located in the oral cavity and orophadynx lining tissue. This is a rare type of oral cancer.

Causes and Risk Factors

The exact causes of oral cancer are not known, but there are a few factors which increase the risk for oral cancer. These risk factors are:
Smoking cigarettes, pipes, or cigars: This is one of the main risk factors that causes oral cancer. Smoking cessation represents one of the most effective prevention approaches.

Use of smokeless tobacco: The risk for oral cancer is also increased when people use smokeless tobacco such as plug, leaf, and snuff. Excessive consumption of alcohol: This is another risk factor that directly causes oral cancer. Studies conducted in developed countries suggest that tobacco and alcohol, together, increases the risk for oral cancer by almost 80 percent because they act synergistically. A deficient diet: The lack of vitamin A, C, and E, iron, selenium, and folate in the diet can increase the risk for oral cancer. Doctors recommend a low-fat, high-fiber diet rich in vegetables and fruits. Exposure to ultraviolet radiation without proper sunscreen protection: The risk for lip cancer is high when exposed to the sun without a proper protection.

Infection with viruses: There are several viruses that seem to increase the risk for oral cancer:

• Human papillomaviruses (HPV) - are a diverse group of DNA-based viruses that infect the skin and mucous membranes within the human body. Studies suggest that infection with HPV 16 and 18 (sexually transmitted viruses) increase the risk for oral cavity cancer and oropharynx cancer.
• Epstein-Barr virus - is a virus from the herpes family that causes an asymptomatic infection called infectious mononucleosis (a medical condition common among young adults and adolescents, characterized by fever, sore throat, muscle soreness, and fatigue, and sometimes, with a development of white patches on the tonsils or in the back of the throat). The connection between the Epstein-Barr virus and oral cancer is still being investigated.
• Herpes simplex viruses causes a viral infection. The connection between this virus and oral cancer is still being investigated.

Medical treatments: Patients that undergo a renal transplant are at a higher risk to develop lip cancer. This risk might be linked to the immunosuppressant effect that can follow the transplant.
Poor oral cavity hygiene and ill-fitting denture: These two factors can increase the risk for developing oral cancer when associated with tobacco use and alcohol consumption, offering a perfect location for tumors to develop.
Age: Men over the age of 40 are at higher risk for developing oral cancer.
Race: African Americans are at higher risk than Caucasians to develop oral cancer.
Gender: Men are at higher risk than women to develop oral cancer.

Signs and Symptoms

Unfortunately, most oral cancers are asymptomatic in the early stages and the symptoms occur when the tumor has reached an advanced stage of development.
Some of the symptoms include:

• A mouth sore or ulcer that does not heal or bleeds easily.
• A white or red patch in the mouth.
• An irritation, lump, or thick patch in the mouth, lip, or throat.
• A discomforting sensation such as something is caught in the throat.
• Chewing or swallowing difficulties.
• Difficulties moving the jaw or tongue.
• Speaking difficulties.
• Hoarseness, chronic sore throat, or changes in the voice.
• Unexplained bleeding in the mouth.
• Unexplained numbness, loss of feeling, pain or tenderness in the face area, mouth, or throat.
• Jaw swelling which causes the denture to not fit anymore.
• Ear pain.
• Unexplained weight loss.

These symptoms vary from patient to patient, depending on the tumor type and location. Only a doctor can establish if the symptoms you display are signs of oral cancer or other medical conditions.

Stages

An important prognostic predictor for oral cancer is the clinicopathologic stage. A clinicopathologic stage describes the cancer developmental phase, and is established according to several criteria: (1) the tumor size, (2) the cancer location, and (3) the cancer extent (how far it has spread).
The most common staging system used for oral cancer is the American Joint Committee on Cancer (AJCC) TNM system. The TNM system refers to: (T) the tumor features -size and invasion level; (N) the lymph nodes involved - lymph nodes are part of the body immune system; (M) the cancer metastasis - metastasis stage is the last developmental cancer stage when the cancer has spread to distal organs (organs situated far from the origin point).

T stage for oral cancer T0: No primary tumor is present. Tis: Carcinoma in situ (the cancer is confined to the tissue where it developed) T1: The tumor is 2 cm or less. T2: The tumor is 4 cm or less. T3: The tumor is larger than 4 cm. T4: The tumor is larger than 4 cm, and it has deeply invaded the muscle, bone, or other adjacent structures.

N stage for oral cancer

N0: No lymphatic nodes are affected.
N1: The cancer has affected one homolateral lymphatic node, but its size is smaller than 3 cm.
N2: The cancer is present in one or more homolateral lymphatic nodes, but their size is smaller than 6 cm.
N3: The cancer is present in a few homolateral or bilateral lymphatic nodes, having a size larger than 6 cm.

M stage for oral cancer

M0: No metastasis are present.
M1: The cancer has spread to distal organs (organs located far from the origin point where the cancer had developed initially).

Based on the TNM system, the oral cancer is classified in four stages:

Stage I: (T1, N0, M0)
In this stage, the cancer is confined to tissue where it initially occurred, and the tumor is not larger than 2 cm.
Stage II: (T2, N0, M0)
In this stage, the tumor is no larger than 4 cm.
Stage III: This stage includes two substages:

Stage IIIA: (T3, N0, M0)
In this stage, the tumor is larger than 4 cm, but no lymphatic nodes or metastasis are present.
Stage IIIB: (T1, T2, T3, N1, M0)
In this stage, the tumor size is either less than 2 cm, under 4 cm, and 4 cm or over, but the cancer has affected one homolateral lymphatic node.

Stage IV: This stage includes three substages:

Stage IVA: (T4, N0, M0)
In this stage, the tumor is larger than 4 cm, and it has deeply invaded the muscle, bone, or other adjacent structures.
Stage IVB: (Any T, N2 or N3, M0)
In this stage, the tumor can have several sizes (1) less then 2 cm, (2) less or more than 4 cm, (3) more than 4 cm but it has deeply invaded the muscle, bone, or other adjacent structures, or the cancer has spread to several homolateral or bilateral lymphatic nodes.

Stage IVC: (Any T, any N, any M)
In this stage, there are several situations which include the tumors having different sizes (between 2 and more than 4 cm), the cancer is present in the homolateral or bilateral lymphatic nodes and in other organs within the body.

Medical Tests & Diagnosis

Oral cancer symptoms can be similar with other medical conditions and only a doctor can establish a correct diagnosis. The diagnosis procedure involves a certain number of steps which include:
Anamnesis (detailed medical review of past health state):
One of the first steps in establishing an oral cancer diagnosis is a detailed and complex medical review of a patient's past health problems and general health state, family medical history, oral cancer risk factors (especially smoking habits, tobacco and alcohol use), and symptoms.
Physical examination
During a physical examination, the doctor examines the oral cavity and pharynx, the face, neck, and lips looking for signs of oral cancer. The doctors looks for any possible lump, abnormal or discolored tissue, or sores.
Imaging techniques

Computed Tomography: This imaging test is similar with an x-ray test, and creates a detailed, cross-sectional image of the body. This test can identify abnormal mass tissues. A CT scan is usually performed in two steps for a better diagnosis outcome: 1). First, the targeted area is scanned without a contrast agent. 2). Second, the targeted area is scanned after a contrast agent was administrated. In patients that suffer from oral cancer, this technique is used to localize metastases. Magnetic resonance imaging (MRI): An MRI is an advanced technique that uses radio waves and strong magnets to reveal a complete image of a targeted area of the body. The energy from the radio waves is absorbed by the tissues and then released into a pattern that allows the cancer to be detected and diagnosed. This technique is also used to establish whether or not the cancer has spread, and to visualize its location within the body.

• Ultrasonography: Ultrasound imaging is a medical technique that uses high-frequency sound waves to create an interior image of the body on a special computer screen. This image is formed from the echoes of the sound waves on the surface of the organs. Abnormal tissue masses and organs reflect sound waves differently. This test involves a device called transducer, that is placed on the upper part of the abdomen, and a computer that translates this sound into an image. Ultrasound imaging is a safe, noninvasive and fast test that can detect tumors.



• Endoscopy: This is a minimally invasive, painless diagnostic procedure used to visualize interior surfaces of certain organs and cavities. During this procedure, a flexible tube, called an endoscope, is inserted into the body in order to provide a clear image of the targeted area. This procedure is used to investigate tissues within the pharynx area which cannot be visualize during a normal examination.
  
  
• Biopsy:
  This is a painless medical procedure that removes a certain amount of tissue for a microscopic examination. This procedure allows the pathologist to establish the nature of the cells and determine whether they are cancerous or not, and the stage of the cancer. In some cases, the doctor might perform a scalpel biopsy. A scalpel is a thin, straight surgical knife used in dissection and surgery. This type of procedure is performed under anesthesia to reduce patient discomfort. 

Treatment Options

The treatment plan for oral cancer varies from patient to patient and is established according to five main factors: (1) the patient's age, general health and past medical history, (2) the cancer type, size, and location, (3) the treatment tolerance, (4) the risk for hidden disease, and (5) the need to save certain functions.
A better treatment outcome is achieved in patients diagnosed with oral cancer in early stages.
The main treatment approach in patients with oral cancer are: surgery and radiotherapy. Chemotherapy is also used to treat oral cancer, but it is usually used in patients with metastasis and it does not represent a primary treatment approach for oral cancer.
Surgery
Surgery is a medical procedure aimed to completely remove the tumor tissue together with adjacent healthy tissue in order to prevent a future cancer relapse.
There are six surgery techniques performed in patients with oral cancer. These are:

1. Primary tumor resection: This is a type of surgery where the entire tumor together with surrounding tissue is removed.
2. Mandible resection: This is a type of surgery where the tumor is removed together with part or the entire jaw bone.
3. Maxillectomy: This is a type of surgery where the tumor is removed together with part or the entire hard palate (the roof of the mouth). This surgery is usually performed when the cancer has spread to the mouth roof bone.
4. Mohs' micrographic surgery: This is an advanced surgically procedure that relies on the microscope accuracy to trace and assure a complete removal of the cancer down to its roots, leaving healthy tissue unharmed. Moh‘s micrographic surgery removes the tumor in thin layers. Each layer of tumor removed is checked under a microscope for cancer cells and the procedure will continue until there are no more cancer cells in the removed layer. This type of surgery can be performed when the tumor is on the lip.
5. Laryngectomy: This type of surgery is performed in patients with large tumors on the tongue or oropharynx. In some cases, the surgeon has to remove the larynx (the voice box).
6. Neck dissection: This type of procedure is performed when the cancer has spread to the lymph nodes within the neck. During this procedure, the tumor is removed together with the lymph nodes affected by cancer.

When performed in early stages, the surgery is small with less post-surgery scars or disfiguration. When performed in advanced stages, the surgery is complex, it removes a substantial amount of tissue, and in most cases requires future reconstruction work.
The side effects are also influenced by the complexity of the surgery and the tumor size. The most common post-surgery side effects include:

• Swelling (the tissue around the operated area can swell for couple of weeks).
• Pain
• Feeling tired
• Weakness

When the removed tumor is too big and the procedure involves removing surrounding tissues or organs (such as palate, tongue, or jaw), the patient can experience the following side effects:

• Disfiguration
• Chewing, swallowing, or talking difficulties

Radiation therapy or radiotherapy This is a local type of therapy that uses high-energy rays or particles to destroy cancerous cells. The purpose of this treatment is to destroy cancerous tissues preserving the healthy tissue. Radiation therapy is used (1) as a curative treatment in patients that cannot be operated on with small tumors, (2) as an adjuvant treatment - in addition to surgery (to enhance the results of the surgery by destroying possible cancerous cells that could have been left behind, and reducing the risk of cancer relapse), 3) as a neoadjuvant treatment - before surgery (to reduce the size of the tumor). There are two types of radiation therapy performed in patients with oral cancer: 1. External beam radiation: This form of radiation therapy uses a device called a linear accelerator that generates an external beam that is concentrated on the tumor area and breaks it up into smaller pieces. Sessions last a few minutes and are administered every day for several weeks.

2. Internal radiation: The radiation is administrated from radioactive materials (such as seeds, needles, thin tubes) inserted into the tumor. When this time of treatment is administrated, the patient has to stay in the hospital.
In some cases, a patient can receive both types of radiation therapy for a better treatment outcome.

Radiation therapy side effects depend mainly on the radiation dosage and the targeted area. The most common side effects displayed by oral cancer patients that undergo radiation therapy are:

• Dry mouth.
• Eating, swallowing, and talking difficulties.
• Mild to major tooth decay (this side effect can be diminished with a correct and good mouth care, keeping the teeth and gums healthy).
• Sore throat or mouth (painful sores and inflammations).
• Sore or bleeding gums.
• Mouth infections (radiation therapy can damage the mouth lining causing infection).
• Delayed healing (radiation therapy can slow down the healing process for the mouth tissue).
• Jaw stiffness (radiation therapy can affect the chewing muscle which leads to difficulties in opening the mouth).
• Denture problems (radiation therapy might cause the denture to not fit anymore).
• Taste and smell changes (during radiation therapy the food might taste and smell different).
• Voice quality changes (the voice might become weak especially at the end of the day).
• Larynx swelling (this also cause the voice to change and the patient can feel a lump in their neck).
• Thyroid changes (radiation therapy might affect the normal function of the thyroid, decreasing the amount of hormones normally produce by this gland. These can cause the patient to gain weight, to feel tired, to have cold sensations, and dry skin and hair.
• Dry, red and extremely sensitive skin in the area exposed to radiation.
• Fatigue.

Most of these side effects can be controlled and diminished with medication.

Chemotherapy

This is a systemic type of treatment (affects cells throughout the entire body) that uses drugs either to stop the abnormal growth and dividing process of the cancerous cells, or to kill them. This treatment also has the ability to interfere with the cancerous cells’ replication.
Chemotherapy can be administrated in combination with surgery and radiation therapy for a better treatment outcome. The chemotherapy drugs can be given intravenous or as pills.
Chemotherapy side effects include:

• Mouth bleeding and deep pain (that is felt like a toothache).
• Dry mouth
• Gums pain
• Taste changes
• Mouth infections
• Temporary hair loss
• Nausea with or without vomiting
• Diarrhea
• Loss of appetite
• Fatigue
• Weakness
• General vulnerability to infection
• Easy bleeding and bruising

These side effects vary from patient to patient according to the drugs and the body reaction to these drugs. Some side effects can be controlled with medication to increase the patient’s comfort during the treatment.