Oral Cavity Cancer

If an adult in your life has oral cancer, you may want to learn more about it. This page has information about oral cavity cancer, its types and what to expect.

First, you should understand what oral cancer is. Cancer is a disease caused by abnormal cells that grow too rapidly. Our bodies are made of cells so tiny you need a microscope to see them. Cancer cells don’t look or act like normal cells, and they don’t allow our normal cells to work properly. There are many types of cancer that can grow anywhere in the body.1 What is cancer? National Cancer Institute.

Oral cavity cancer is also known as mouth cancer. Mouth cancers typically start as a lump, bump or patch in the mouth (called “lesions”). Something unusual that does not go away after a few weeks is usually found by a dentist or a doctor, if not by the patient.

Your loved one may have noticed a lump or swelling in his or her mouth and brought it to the attention of a doctor. Not every lump or bump is cancer, but it is a good idea to ask a doctor when you are not sure. The earlier cancer is found, the better the outcome.

Understanding the anatomy

To understand oral cavity cancer, you need a basic understanding of the anatomy (parts) of the head and neck.

02a_mouthsitesThis drawing shows different parts of the mouth. Basically, the mouth includes everything from the pink part of the lips to the bony roof of the mouth, as well as the part of the tongue that is visible when you open your mouth.

Oral cavity cancers can start in seven different areas within the mouth called subsites. Keep in mind that the soft palate, uvula (dangly bit of tissue in the back of the mouth) and the base of the tongue are actually part of the oropharynx (back of the throat), not the oral cavity.

The different subsites of the mouth include:

Mucosal lips: The upper and lower mucosal lips start at the vermillion border (the meeting of facial skin and pink lip) and end where the lips touch each other.

Buccal mucosa: This is the pink lining inside the lips and cheek. It goes from the inside part of the lips that you can’t see when the mouth is closed to the gums and along the inner part of the cheek. Oral tongue: This is the front two-thirds of the tongue, the part that moves around easily. When describing a tumor of the oral tongue, doctors will say it is either on the tip, lateral border (the side), the dorsum (the top) or the ventral surface (the bottom). Floor of mouth: This is the part in the front or side of the mouth that you can see if you lift your tongue up to the roof of your mouth. It goes from the gingiva (gums) on the inside of the mandible (lower jawbone) just to the bottom of the tongue. The lingual frenulum divides the floor of the mouth into a left and right side. Upper and lower alveolar ridge: This is the gums, or the pink lining that is attached to the upper jawbone (maxilla) and lower jawbone (mandible) behind the top and bottom teeth. Retromolar trigone: This is the lining (mucosa) on each side of the mouth. It is attached to bone in the back corner of the mouth behind the very last lower tooth and forms a triangle between the upper and lower jawbones. It is a thin piece of mucosa that sits over part of the lower jawbone. Hard palate: This is the bony part of the roof of the mouth. The soft palate is located behind the hard palate and is actually considered part of the oropharynx (throat).

Causes of oral cavity cancer

You may want to know what caused the oral cavity cancer. The short answer is that we don’t know. Most cancers in the head and neck are caused by drinking too much alcohol and smoking. You can be sure that you did nothing to cause it. Also, it is not contagious (you can’t catch it). In most cases, it’s a combination of genetics and the environment.[ref]2[/ref]
  • Tobacco: This is the most common cause of oral cavity cancers. Smoking cigarettes, cigars or pipes and using chewing tobacco greatly increase the chance of getting an oral cavity cancer.[ref]3[/ref]
  • Alcohol: Drinking too much alcohol is strongly associated with getting oral squamous cell cancers. And if you both smoke and drink heavily, the risk more than doubles.[ref]3[/ref]
  • Betel nut: This is the seed of the areca tree. It is often chewed by people from Southeast Asia and is known to cause oral cavity cancer.[ref]3[/ref]
  • Ultraviolet exposure from the sun: This is responsible for almost all lip cancers.
Other factors that can increase the chance of getting oral cavity cancer include[ref]4[/ref]:
  • Marijuana
  • Bad dental hygiene
  • Viruses
  • Food and nutrition
  • Genetic factors

Signs and symptoms of oral cavity cancer

In most cases of cancers in the mouth, either the patient or the patient’s dentist or general doctor saw or felt something unusual. This is different from cancers in other parts of the head and neck, which can be harder to detect. Possible symptoms from oral cavity cancer include:
  • Painful sores in the mouth: Usually, an oral cavity cancer will start as a painful sore in the mouth. In some cases, a dentist or dental hygienist will see a sore in the mouth that the patient didn’t know was there. In general, a patch or sore in the mouth that doesn’t heal after a few weeks should be evaluated in more detail by a specialist.
  • A patch in the mouth: A red patch (erythroplakia) in the mouth that lasts for more than a few weeks is more likely to be cancer than a white patch.[ref]5[/ref] However, any lesion that doesn’t go away should be biopsied (tested) to tell whether it is cancer.
  • Frequent bleeding in the mouth: This can happen when the cancer makes a hole in some part of the mouth (an ulcer) or if cancer cells are accidently rubbed off while brushing teeth or eating certain foods.
  • Bad breath: In rare cases, when cancer cells start to die, the dead cells can lead to a bad smell from the mouth called halitosis.
Sometimes a dentist or oral surgeon will see something in the mouth, remove it and a week later get the report that it is a cancer. Other symptoms may include, especially if the cancer has invaded other areas:
  • Loose teeth or dentures that don’t fit correctly: This happens if the tumor gets into the tooth sockets or the bones where the teeth are rooted.
  • Difficulty opening the mouth: This can happen if the cancer gets into any of the muscles that help to open and close the mouth. This is called trismus.
  • Numbness (for example in the lower teeth or lower lip/chin area): This means the cancer cells have gotten into nerves that allow feeling. The main nerve responsible for this when dealing with oral cavity cancer runs just inside the lower jawbone, and a branch even runs in the middle of the jawbone and comes out under the skin of the chin.
  • Pain or difficulty with swallowing: This can happen when tumors get large and either get in the way of eating or involve the muscles and nerves of swallowing.
These symptoms sound scary, but don’t jump to conclusions. A person could have one or more symptoms but NOT have an oral cavity cancer. There are several non-cancerous causes of the same symptoms. That’s why he or she needs to see a specialist.

What will happen at the doctor visit

Step 1: History First, the doctor will listen to the patient talk about his or her health. The doctor will probably ask many questions, too. The doctor might ask some of these questions:
  • How long has the problem been there?
  • Is it getting worse, better or staying the same?
  • Does it come and go?
  • Have you tried anything to make it better?
  • Is it painful?
  • Do you have numbness or tingling anywhere in your face or mouth?
  • Do you have any lumps or bumps in your neck?
  • Are you losing weight?
  • Do you have any other medical conditions?
  • Have you had any surgeries in the past?
  • What medications do you take? And do you have any allergies?
  • Have you ever been exposed to radiation in the head and neck?
  • What do you (or did you) do for a living?
  • Do you have a family history of cancer?
Step 2: Physical Exam Next, the doctor will look at and feel the patient’s head and neck. There are a few “red flags” (danger signs) the doctor will look for. These raise the chances that a lump is really cancer. Some of these “red flags” include:
  • There is weakness in the face on the side of the lump.
  • The lump is attached to the skin on top of it.
  • The skin inside the mouth has a sore or looks different from the skin around it.
  • There is numbness or tingling in certain parts of the face.
  • The inside of the ear canal has a sore or lump.[ref]5[/ref]
The doctor will also check the facial nerve by having the patient move his or her face. This tests if the cancer has grown into the nerve. Nerves are important because they control muscle movements and feeling in the face. Step 3: Reviewing Tests After getting background information and doing a physical exam, the doctor will look at the results of any tests the patient has already had. Step 4: Suggestions Finally, the doctor will make suggestions about next steps. This will probably include more tests and doctor visits.

Diagnosing oral cavity cancer

If the patient has a lump with any “red flag” symptoms, the doctor will be worried that it might be a type of oral cavity cancer. To check if it is really cancer, the doctor will choose one or more of the following actions. Removal Most growths (lumps or tumors) in the mouth are not really cancer. The usual way to deal with oral tumors, whether they are cancer or not, is to remove them. Therefore, some doctors will decide to do surgery to take out any tumors without doing more tests. In the operating room, the surgeon can see the whole tumor and learn more about it. The surgeon can then send whatever was removed to be tested. Another doctor, called a pathologist, will look at the cells under a microscope to decide if the tumor is cancer or not. Imaging Imaging refers to radiologic studies, or scans, that make pictures of the structures inside the head and neck. In general, imaging might not be necessary for small tumors that can be easily seen by the doctor. For larger tumors, or tumors in locations difficult to examine, the doctor will probably order some sort of imaging to get more information about the tumor location to see if the tumor has spread to nearby lymph nodes. An important reason to get a scan for sinonasal tumors is to see if there is any evidence of spread into nearby structures. Spread into other structures will influence what treatment the doctor recommends. Some surgeons also say getting some imaging (pictures of the inside of the head and neck) will lower the chance of surprises in the operating room. Imaging will also give some clues about whether the tumor is really cancer. This will prepare the patient and the surgeon for what to expect during surgery. There are many different kinds of imaging scans. The doctor may recommend more than one kind of scan to see a better picture of the tumor. The two main types of imaging used in the U.S. are CT scans and MRI scans.
 CT Scan  MRI
Advantages A computed tomography (CT) scan is a quick test that shows a great deal of useful information. A CT scan can show the size of the tumor and how far it has spread. It can help a surgeon plan an operation. Magnetic resonance imaging (MRI) is better at showing how the tumor has spread to body parts around it. The patient will not be exposed to radiation during an MRI.
Disadvantages A CT scan uses radiation, which can be dangerous.The pictures might not be clear if the patient moves or has a lot of dental work. Also, a CT doesn’t show damage to nearby body parts as clearly unless the damage is moderate to severe. An MRI takes a lot longer than a CT scan. It requires the patient to lie perfectly still for almost an hour. The patient can’t have an MRI if he or she has metal implants.
For most head and neck cancers, if imaging is required, the doctor will likely start with a CT scan with contrast. Other tests might include an MRI and/or a positron emission tomography (PET) scan. Biopsy A biopsy is the main way to find out if a growth is cancer. For a biopsy, the doctor takes out a small piece of the lump or the entire tumor. Another doctor, called a pathologist, then looks at the sample under a microscope to see if it is cancer. Doctors often do biopsies because they can usually be done quickly and safely. The doctor can sometimes do a biopsy during the first visit, and there is a very low chance of anything going wrong. Fortunately, almost all tumors in the mouth can be biopsied in the office with a little numbing medicine (either a spray or a tiny injection or both). It will usually only take a few seconds to do the biopsy. In some cases, however, the doctor may want to do the biopsy in the operating room, especially if he or she is concerned the tumor has spread to the neck or throat. A biopsy can help the doctor plan the surgery if he or she decides to take out the whole tumor. A biopsy can also prevent unnecessary surgery. As good as biopsies sound, there are a few problems. First, biopsies are not 100 percent accurate. A biopsy could show that a growth is NOT cancer when it really is; this is called a false-negative biopsy. A false-positive is also possible when the biopsy seems to show that a growth is cancer but more testing shows it isn’t. Sometimes doctors can’t be sure from a biopsy.

Determining the type of oral cavity cancer

After the tumor has been closely looked at, the doctor will need to figure out what type of cancer it is. He or she may be able to tell from biopsy results. The doctor may also want a second opinion from a specialist to be sure. If the person does have cancer, it will most likely be squamous cell carcinoma.
  • Squamous cell carcinoma: This cancer starts from abnormal cells on the surface layer of the lips or mouth lining. More than 85 percent of mouth cancers are squamous cell carcinomas.[ref]6,7[/ref]
  • Carcinoma in situ (also called severe dysplasia): This is really an early stage of squamous cell carcinoma. It is called carcinoma in situ when cancerous cells on the tissue line the oral cavity but have not invaded past the outermost layer of tissue. These should be removed completely, before they start invading (penetrating deeper).
  • Verrucous carcinoma: This type of squamous cell carcinoma has a better outcome because it is less likely to spread. It should be treated as any other squamous cell carcinoma.[ref]8[/ref] There are a few other subtypes of squamous cell carcinomas as well.
Other cancers that can start in the mouth include:
  • Salivary gland cancers: This cancer affects minor salivary glands located under the lining of the mouth. See Salivary Gland Cancer for more information. In rare cases, salivary gland cancers may grow inside the bone itself.
  • Lymphoma: This cancer grows in lymphoid cells, which are located throughout the body, including the lining of the mouth. In rare cases, lymphoma can appear as a lump in the mouth.
  • Mucosal melanoma: These cancers come from skin cells (melanocytes) that give skin its color. In rare cases, melanoma can be found in the lining of the mouth, nose and/or throat.
  • Kaposi’s sarcoma: This cancerous tumor is usually associated with AIDS. While it usually appears on the skin, it can be found with a similar appearance in the mouth. In the mouth it looks like a purple lesion filled with blood vessels.
  • Osteogenic sarcoma (also called osteosarcoma): This type of bone cancer typically begins in the long bones of the arms and legs, though it can also occur very rarely in the jaw. It is the most common type of bone cancer among children and adolescents.
The doctor will determine the treatment for the cancer based on the category (type), grade (abnormality) and stage (severity) of the tumor.

Determining the grade of the tumor

Pathologists will typically report on the grade of the tumor. This is a pathologist’s interpretation of how much the cancerous cells resemble normal tissue from that site. There are a number of different grading systems that might be used. The most common is as follows:
  • GX: Grade cannot be assessed
  • G1: Well differentiated
  • G2: Moderately differentiated
  • G3: Poorly differentiated
  • G4: Undifferentiated
Differentiation refers to how closely the cells taken from a tumor or lesion resemble normal cells from the healthy tissue surrounding the tumor. “Well differentiated” means that the cells look similar to normal cells in that area. “Undifferentiated” means the cells look nothing like normal cells in that area. While it is important to report the tumor’s grade, few doctors use this information to make decisions regarding treatment or prognosis for this particular cancer type.

Determining the stage of the cancer

The final step before treatment is identifying the stage or the extent of the cancer. This will be based on all of the available information. Stage is based on the physical exam, imaging studies, laboratory work and biopsies. Like with all cancers of the head and neck, doctors in the U.S. use the AJCC Cancer Staging Manual (7th Ed) to figure out the stage based on three factors.
Factors that go into determining the stage of the cancer
T Characteristics of the main tumor mass
N Status of the lymph nodes in the neck (evidence of cancer spread)
M Status of cancer spread to parts of the body outside of the head and neck
T stage: the main tumor Based on a physical examination and review of any imaging, the doctor should be able to assign a T stage that falls within one of the following categories.


Tx The doctor is unable to assess the main tumor.
T0 The doctor is unable to find the main tumor.
Tis Carcinoma in situ (or severe dysplasia); this means there are cancer type cells, but they have not yet invaded deep into tissue. This is more of a pre-cancer lesion.
T1 The tumor is 2 centimeters or less in greatest size.
T2 The tumor is more than 2 centimeters but less than or equal to 4 centimeters in greatest size.
T3 The tumor is more than 4 centimeters in greatest size.
T4a This is moderately advanced local disease. The tumor clearly invades into the skin of the face, through the upper or lower jawbone, into the nerve that allows you to feel the teeth and chin area or into the floor of the mouth. For lip cancer, the tumor is in this stage if the tumor clearly invades into the skin of the face, through the upper or lower jawbone, or into the nerve that allows you to feel the teeth and chin area, or the floor of the mouth.Note: A little bit of bone or tooth socket invasion from a tumor of the gums does NOT make it a T4a cancer.
T4b This is very advanced local disease. This stage is assigned if the tumor is invading into the masticator space, pterygoid plates, base of the skull and/or encases the carotid artery.
N stage: spread of cancer to the lymph nodes in the neck Next, the doctor will use all the available information to figure out the N stage. This is based on the assessment as to whether the cancer has spread to lymph nodes in the neck. 06_Nstages
Nx The neck lymph nodes cannot be assessed.
N0 There is no evidence of any spread to the nodes.
N1 Cancer has spread to a single lymph node on the same side of the main tumor, and it is 3 centimeters or less in greatest size.
N2a Cancer has spread to a single lymph node on the same side as the main tumor, and it is more than 3 centimeters but less than or equal to 6 centimeters in greatest size.
N2b There are multiple lymph nodes that have cancer on the same side as the main tumor, but none are more than 6 centimeters in size.
N2c There are lymph nodes in the neck on either the opposite side as the main cancer or on both sides of the neck, but none are more than 6 centimeters.
N3 The cancer has spread to one or more neck lymph nodes, and the size is greater than 6 centimeters.
M stage: spread of cancer outside the head and neck Finally, the doctor will identify an M stage. The M stage is based on an examination of the entire body.
M0 No evidence of distant (outside the head and neck) spread.
M1 There is evidence of spread outside of the head and neck (i.e., in the lungs, bone, brain, etc.).
The cancer stage After TNM staging, the doctor can assign a cancer stage based on the following chart.
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage III T3 N0 M0
T1 N1 M0
T2 N1 M0
T3 N1 M0
Stage IVA T4a N0 M0
T4a N1 M0
T1 N2 M0
T2 N2 M0
T3 N2 M0
T4a N2 M0
Stage IVB Any T N3 M0
T4b Any N M0
Stage IVC Any T Any N M1
The clinical stage Once the tests are completed, and before deciding on a treatment plan, the patient should be given a clinical stage that looks like this:
Site Oral Cavity
Subsite Left Buccal Mucosa
Type Squamous Cell Carcinoma
cT cT3
cN cN1
cM cM0
cStage cIII

Deciding on a treatment plan

Like with all cancers in the head and neck, there are three general treatment options, which may be used alone, together, or one after the other: The latest National Comprehensive Cancer Network (NCCN®) Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Head and Neck Cancers will help the doctor suggest the best treatment.[ref]9[/ref] Let’s look at the types of treatments available. Surgery The main treatment for almost all oral cavity cancers is complete surgical removal of the tumor. The surgeon will cut out the tumor plus a little bit of normal tissue around it to be sure to get all the cancer. Another doctor, called a pathologist, will look at the entire tumor under a microscope to identify a more exact stage for the tumor. This report, called the pathologic stage, can help the doctor decide if radiation and/or chemotherapy are needed. Radiation Radiation therapy kills cancer cells with high-energy radiation such as X-rays or gamma rays. Radiation may be used as a main treatment for tumors that cannot be easily removed. The surgeon will use radiation alone or radiation with chemotherapy, depending on the characteristics of the tumor. Radiation is also often used after surgery to lower the chances that the tumor will come back. Chemotherapy Chemotherapy, or “chemo,” uses drugs to kill cancer cells. It is especially helpful when:
  • Cancer has spread beyond the head and neck.
  • There is a T3 or T4 tumor in which surgery cannot remove all of the tumor.
  • There is a T3 or T4 tumor that has certain bad features found under the microscope, such as intermediate or high grade.
  • There are close margins (meaning that when the tumor was removed, some cancer cells near the edge of the tumor may have been left behind).
  • There is growth into nerves.
  • There is spread into lymph nodes.
  • There is growth into lymphatics or vessels.

Determining the prognosis

The prognosis is a prediction of how the treatment will turn out. How likely is it that a person with cancer will be cured? Will the cancer come back? How will life change? These are the big questions on most people’s minds when they find out that someone they love has cancer. The following characteristics of the cancer may affect the chances of a cure.
Factors That Can Affect the Chances of Being Cured
Stage This is the most important factor that affects the chances of being cured. Cancers in earlier stages usually have better outcomes.
Type and Grade The type and grade of tumor show how aggressive a tumor is.
Spread to Lymph Nodes If there is spread to lymph nodes in the neck, there is a lower chance of a cure.
The Tumor Margins (edges) Some say the ability to completely remove the tumor is the single most important factor in whether a person will be cured.
Spread into Nearby Body Parts Spread into large nerves, skin and bone has been shown to indicate a worse prognosis.

What to expect after treatment is completed

After making it through treatment, the patient will need to follow up closely with the doctor using recommendations from the NCCN Guidelines®.[ref]9[/ref] Follow-up doctor visits and testing are to make sure the cancer doesn’t come back or to catch it quickly if it does. In general, the person should have regularly scheduled doctor’s visits every one to three months for the first year, every two to six months in the second year and every four to eight months in the third to fifth year. After making it past the first five years, the patient can then see the doctor once a year.


1 What is cancer? National Cancer Institute.

2 Petersen PE. Oral cancer prevention and control – The approach of the World Health Organization, Oral Oncol. 2008.

3 Ko YC, Huang YL, Lee CH, Chen MJ, Lin LM, Tsai CC. Betel quid chewing, cigarette smoking and alcohol consumption related to oral cancer in Taiwan. Journal of oral pathology & medicine: official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology. Nov 1995;24(10):450-453.

4 Shugars DC, Patton LL. Detecting, diagnosing, and preventing oral cancer. The Nurse Practitioner. Jun 1997;22(6):105,109-110,113-105 passim.

5 Neville BW, Day TA. Oral cancer and precancerous lesions. CA: a cancer journal for clinicians. Jul-Aug 2002;52(4):195-215.

6 Kademani D. Oral cancer. Mayo Clinic proceedings. Mayo Clinic. Jul 2007;82(7):878-887.

7 Funk GF, Karnell LH, Robinson RA, Zhen WK, Trask DK, Hoffman HT. Presentation, treatment, and outcome of oral cavity cancer: a National Cancer Data Base report. Head neck. 2002 Feb;24(2):165-80.

8 Kraus FT, Perezmesa C. Verrucous carcinoma. Clinical and pathologic study of 105 cases involving oral cavity, larynx and genitalia. Cancer. Jan 1966;19(1):26-38

9 Referenced with permission from The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Head and Neck Cancers V.2.2014. © National Comprehensive Cancer Network, Inc 2014. All rights reserved. Accessed June 18, 2014. To view the most recent and complete version of the guideline, go online to NATIONAL COMPREHENSIVE CANCER NETWORK®, NCCN®, NCCN GUIDELINES®, and all other NCCN Content are trademarks owned by the National Comprehensive Cancer Network, Inc.