Oral Cancer: All the Facts You Need to Know
Oral Cancer Facts
Oral cancer is the most common head and neck cancer.
About 11.5 out of 100,000 adults will get oral cancer (2).
The most common type is called squamous cell carcinoma.
The main risk factors are heavy smoking and drinking (6).
If you smoke and drink a lot, you're 35 times more likely to get oral cancer than if you don't do both (6).
In this article:
1. What is Oral Cancer
2. How Does Oral Cancer Occur
3. How Does Oral Cancer Progress
4. The Different Types of Oral Cancer
5. The Areas of the Mouth Most Likely to Develop Cancer
6. Risk Factors for Oral Cancer
7. The Warning Symptoms
8. Oral Cancer Treatment
9. How to Inspect Your Mouth at Home
What is Oral CancerOral cancer is a type of head and neck cancer, and it's quite common. In fact, about 11.5 adults out of every 100,000 will develop oral cancer.
The risk of developing it tends to increase as we get older. Historically, it has been more common in men, with a ratio of 1 male affected for every 6 females. But that's changing because more women are now exposed to risk factors like smoking and alcohol.
So, what exactly is oral cancer? Well, like any cancer, it starts when our cells start growing and multiplying abnormally due to changes in their genes. These genes regulate how our cells grow and divide. When something goes wrong, cells can start growing uncontrollably, forming a noticeable lump or tumor.
There are several types of oral cancers. Their names differ depending on the type and origin of the tissue where it originates. In about 9 out of 10 cases, oral cancer is called Squamous Cell Carcinoma. (1) This name comes from the squamous cells that line the outer mouth layer.
But sometimes, it can also start in other tissues, like the salivary glands, fat, nerves, or blood vessels.
When detected early, the odds of successful recovery can be as high as 90%. But sadly, most cases are diagnosed late.
How Does Oral Cancer OccurThe development of oral cancer is a bit complex and not fully understood, but we do know that it's an interaction between certain environmental factors and genetics (3-7).
Factors like tobacco, alcohol, and viral infections can damage our DNA and kickstart the process of cancer development.
To grasp this, we need to know about two types of genes that regulate cell growth systems: Proto-oncogenes and Tumor Suppressor Genes.
Proto-oncogenes are like boosters, encouraging cells to divide and multiply. Tumor suppressor genes, on the other hand, act like brakes, slowing down cell growth.
When a mutation occurs in a proto-oncogene, it turns into a hyperactive version called an oncogene. This results in normal cells growing wildly and uncontrollably.
On the flip side, our body has a DNA repair system, where tumor suppressor genes come into play. They fix DNA damage and prevent cells from growing too fast. But if these genes also mutate, they stop doing their job, and cells proliferate rapidly, ultimately causing cancer.
How Does Oral Cancer ProgressAt first, the cancerous growth is confined to where it began. But as it progresses, it can invade nearby tissues and even spread to lymph nodes in the neck. In advanced stages, it can even spread to other organs, like the lungs or liver, and we call this metastasis.
To determine the actual stage of the cancer, we use a simple system called TNM:
- T: This tells us the size of the tumor. T1 means it's small, about 2 centimeters or less. T3 suggests it's larger, over 4 centimeters, and T4 means it's no longer limited to the tissue where it started.
- N: This indicates whether the cancer has spread to the lymph nodes. Normally, these nodes are tiny and invisible, helping filter out bad stuff from our bodies. But when cancer cells invade them, they can become quite large.
- M: This refers to metastasis, which means cancer has spread to distant organs.
When cancer reaches the lymph nodes, it's easier for it to spread to vital organs (5). In such case, the 5-year survival rate drops to about 40% (4).
The Different Types of Oral CancerAgain, oral cancer typically presents as squamous cell carcinoma in more than 90% of cases. However, there are less common forms that originate from different tissues:
- Malignant Melanoma: This cancer arises from melanocytes, the cells responsible for skin and mouth pigmentation. In the mouth, it results in the rapid growth of dark brown or black patches, often leading to painful, large masses.
- Osteosarcoma: As the name suggests, this malignant tumor develops in the bone, specifically the jawbone in the mouth. It causes rapid and painful swelling, leading to severe deformities and facial distortion.
- Fibrosarcoma: This cancer originates from fibroblasts, the deepest layer of skin cells. The excessive growth of these cells results in a painful mass that rapidly invades surrounding tissues.
- Liposarcoma: Derived from fat-containing cells known as lipoblasts, this rare tumor in the mouth manifests as soft lumps with a yellowish coating.
The Areas of the Mouth Most Likely to Develop CancerWhile cancer can affect any part of the mouth, certain areas are more prone to squamous cell carcinoma (1):
- The Tongue: Carcinoma of the tongue accounts for about 50% of all oral malignancies, with most cases involving the left or right sides.
- The Lips: Squamous cell carcinoma of the lips constitutes roughly 20% of all oral cancers, with the lower lip being the most commonly affected.
- The Floor of the Mouth (Underneath the Tongue): This is the third most common site for oral squamous cell carcinoma. Heavy alcohol and tobacco use are strongly associated with cancer in this particular region.
- Soft Palate (Back of the Roof of the Mouth): Approximately 15% of all oral carcinomas occur in this area.
- Inside the Cheeks and Gums: These are the least affected, accounting for only 1% to 6% of oral cancer cases.
Risk Factors for Oral CancerSeveral factors can increase the risk of developing oral cancer by inducing mutations in the genes we discussed earlier. Over time, these mutations can accumulate and turn healthy cells cancerous. These risk factors include:
- Smoking: Tobacco in all forms, whether smoked or smokeless, poses a significant risk, accounting for 90% of oral cancer cases. The risk increases with the quantity and duration of tobacco use due to the presence of over 70 cancer-inducing chemicals in cigarettes, according to the Mouth Cancer Foundation.
- Alcohol: About 75% of individuals with oral cancer are alcohol consumers. People who smoke and drink together are 35 times more at risk than those who do neither (6). This is due to the synergic effect of these two substances. Alcohol weakens the mouth's protective lining, making it more susceptible to other carcinogens. Additionally, alcohol is broken down in the mouth into acetaldehyde, a toxic chemical that raises the risk of squamous cell carcinoma.
- Viral Infection: Human papillomavirus (HPV) is a commonly suspected viral infection that may play a role in oral cancers.
- Chronic Irritation or Trauma: Repeated minor trauma or injury to mouth tissues can trigger malignant cell transformations.
- Certain Oral Conditions: Conditions like leukoplakia, lichen planus, and erythroplakia are known to carry precancerous potential. While they initially appear as benign lesions, without treatment and in the presence of risk factors, they can become malignant.
The Warning SymptomsRecognizing the early signs of oral cancer is crucial for timely treatment.
Yet, in its initial stages, cancer can be sneaky, manifesting as minor issues like mild inflammation. That's why it's always wise to consult a dentist or healthcare professional for any unusual or slight changes in your mouth. Here are common signs to watch for:
- Ulcers That Won't Heal: While mouth ulcers, including Canker Sores, typically heal within a week or two, persistent ulcers may be a sign of oral cancer. Another similar and common ulcerative condition is called Traumatic Ulcer. It is due to an injury to the mouth by a hard toothbrush, a hot drink, or a harsh mouthwash. These injuries should also heal once the source of trauma is removed. However, if an ulcer persists without healing and is associated with swollen lymph nodes or bleeding, see your dentist promptly.
- Red or White Patches: These patches may indicate precancerous conditions, although they can also result from nutritional deficiencies, anemia, or other benign conditions like geographic tongue (red patches resembling a map on the tongue).
- Abnormal Growths: Most oral lumps are benign, but it's a good idea to consult a healthcare professional if you notice an abnormal growth. Common benign mouth tumors, like Fibromas and Mucoceles, are usually small, painless, and slow-growing, not invading surrounding tissues.
- Persistent Lumps in the Neck or Under the Lower Jaw: Swollen lymph nodes in the neck can indicate inflammation, infection, or potentially invading cancer. As a precautionary measure, it's advisable to seek professional evaluation.
- Other Symptoms: Unexplained bleeding, numbness, or pain that persists for more than 15 days or recurs should prompt a visit to your dentist. These symptoms don't necessarily point to cancer, as they can arise from various benign oral conditions. But it's essential to rule out any serious concerns.
Oral Cancer TreatmentTreatment for oral cancer primarily involves three options: surgery, radiotherapy, and chemotherapy. The choice depends on the type of cancer and its extent.
In early-stage cancer, surgery alone may be sufficient. In advanced cases, surgery is often complemented by radiotherapy and chemotherapy to target cancer cells that have spread beyond the primary site.
The potential for a complete cure and survival rates depend mainly on the cancer stage. According to the American Society of Clinical Oncology (ASCO), the 5-year survival rate is 86% when diagnosed early. However, if lymph nodes are affected, the survival rate drops to 69%, and with metastasis, the chances of survival do not exceed 40%.
How to Inspect Your Mouth at HomeTo be on the safe side, make it a routine to regularly inspect your mouth for any unusual signs or changes. Check all areas inside your mouth, including the roof and floor, tongue, inner cheeks, and gums.
To get a better view of the less accessible regions, you can gently use your fingers or a spoon to separate your tongue, lips, and cheeks. This will let you inspect the two sides of your tongue, the areas most prone to oral cancer.
If any ulceration persists for more than 15 days, even after addressing all potential injury sources, it should be investigated by your dentist or general practitioner. The same goes for white or red spots, unusual bleeding, and persistent pain.
Even if the spot or sore doesn't look serious, it's essential to rule out cancer, as a late diagnosis can make recovery more challenging.
- Essential Of Oral Pathology - Book by Swapan Kumar Purkait
- Oral Cancer Incidence (New Cases) by Age, Race, and Gender | National Institute of Dental and Craniofacial Research (nih.gov)
- Molecular pathogenesis of oral squamous carcinoma - PMC (nih.gov)
- Oral and Oropharyngeal Cancer: Statistics | Cancer.Net
- Cancer in Lymph Nodes May Help Tumors Metastasize - NCI
- fdi-oral_cancer-prevention_and_patient_management-fr.pdf (fdiworlddental.org)
- Smoking and Drugs | Mouth Cancer Foundation