What is Premalignant Lesions of the Oral Mucosa?
“Premalignant oral disorder” is a term that covers a range of conditions that can occur in your mouth. Catching these early and treating them quickly helps ensure the best health outcomes. However, many doctors are not fully informed about these disorders. Recent research showed that less than half of medical practitioners knew about the common risk factors of premalignant oral disorders or oral cancer. Similarly, many doctors did not have a good understanding of common premalignant oral conditions. It’s clear there is a great need for better understanding and recognition of these conditions, including how they come about, what their effects on the body are, and how they should be managed.
The term “oral cavity” refers to a specific area that includes the lips, gums, the inside of the cheeks (“buccal mucosa”), gum or tooth socket (“gingiva/alveolar ridge”), the roof of the mouth (“hard palate”), the bottom of the mouth and two-thirds of the tongue. The vestibule is the part of your mouth that includes the cheek and lip aspect of your teeth, as well as the mucosa of tooth socket and the wet lining of the lip. The oral cavity is mostly lined by a type of tissue called “stratified squamous epithelium.” Abnormal changes in this tissue often lead to premalignant oral lesions
The most frequently found premalignant oral disorders are leukoplakia, erythroplakia, lichen planus, and submucous fibrosis. We will go over the causes, changes in body function, important history and exam findings, as well as treatment options for these precursors to oral cancer.
What Causes Premalignant Lesions of the Oral Mucosa?
Main causes of pre-cancerous mouth sores are habits like smoking, using tobacco products, and consuming alcohol. Chewing betel nuts has also been linked to the development of a condition called oral leukoplakia, which appears as white patches in the mouth.
Another risk factor that has been detected is the human papillomavirus (HPV). According to a review of 52 studies, it was found that 22.5% of pre-cancerous mouth disorders had HPV DNA present in them. Furthermore, the most common type of HPV found was HPV16, which is also commonly found in a type of throat cancer known as oropharyngeal cancer.
Risk Factors and Frequency for Premalignant Lesions of the Oral Mucosa
Oral premalignant lesions, which are potential precursors to oral cancer, appear in about 1.5% to 4.5% of people globally, and are more common in men than women. These rates are higher in Asian, South American, and Caribbean populations, mainly due to differences in tobacco and alcohol use. These conditions contribute to 17% to 35% of all new oral cancer cases and can evolve into malignant, or cancerous, lesions at a yearly rate of 0.7% to 2.9%.
- Oral premalignant lesions are found in about 1.5% to 4.5% of people worldwide.
- These types of lesions are more common in men than in women.
- Populations in Asia, South America, and the Caribbean have higher rates, largely due to varying levels of tobacco and alcohol use.
- These lesions account for 17% to 35% of all new cases of oral cancer.
- Every year, between 0.7% and 2.9% of these lesions turn into cancer.
Signs and Symptoms of Premalignant Lesions of the Oral Mucosa
When analyzing mouth sores or lesions, careful examination and close scrutiny of physical signs is necessary. If a doctor suspects a lesion could turn into cancer, they will want to know how long the lesion has been there, how it has changed over time, whether there’s been any pain, recent dental injuries, bleeding, difficulty swallowing, painful swallowing, jaw tightness, or weight loss. It’s also important to find out if the patient smokes or drinks alcohol frequently, as these habits may contribute to such lesions. A complete medical history is crucial, especially if the patient has autoimmune diseases or a history of organ transplantation, as these individuals have an increased risk of developing mouth cancer.
Some viruses, such as HIV and Hepatitis C, can make people more prone to pre-cancerous oral lesions. For instance, people with Hepatitis C often also have a condition called oral lichen planus. A thorough physical examination should include the size, shape, description, color, firmness, and location of the lesion, as well as checking for swollen glands in the neck or near the cheek.
- Leukoplakia is usually a white patch or plaque in the mouth, which does not wipe off.
- Erythroplakia can appear as a solid red patch or plaque. Both these conditions are typically non-painful and can appear anywhere in the mouth, including the inside of the lip, mouth floor, tongue, or cheek lining.
- Oral submucous fibrosis often involves the tongue and sometimes the back of the mouth. It often results in pale, patchy discoloration and might cause jaw tightness in severe cases.
- Oral lichen planus can look like an ulcerative, painful lesion with a fine net-like appearance, often on the tongue or cheek lining.
The exact appearance of these conditions can vary significantly, as shown in several illustrated examples of leukoplakia.
Testing for Premalignant Lesions of the Oral Mucosa
If there might be pre-cancerous changes happening in your mouth, your doctor will need to do a thorough hands-on examination and very likely a biopsy as well to gather more info. The biopsy is where they’ll take a small sample of the affected tissue to study it under a microscope to rule out cancer. If the area involved is large or covers multiple sections of your mouth, your doctor may need to take samples from several places.
If the lab sees moderate or severe dysplasia, which are abnormal cells that could turn into cancer, on your biopsy, you would likely need more surgery to remove the whole area to rule out cancer altogether.
Additionally, if there’s concern that the disease may have spread or the presence of lumps in the neck, your doctor may also have you go through a special type of body scan, called a Computed Tomography (CT) scan, from the base of your skull to your collarbone, alongside other necessary checks. This scan helps to give a more detailed view of the concerning area and helps to determine the stage (how far it’s spread) if cancer were to be found.
Treatment Options for Premalignant Lesions of the Oral Mucosa
The main aim of managing precancerous oral lesions is to prevent the development of oral cancer. The treatment approach depends on the specific characteristics of the lesion and the patient’s personal preference. For less risky lesions, simply stopping behaviors like drinking alcohol, using tobacco, or chewing betel nut, coupled with regular check-ups, can be an effective strategy.
However, for high-risk lesions (those showing moderate or severe abnormal cell changes, or those located in risk-prone areas like the edges of the tongue or the floor of the mouth), the removal of these lesions, known as an excisional biopsy, is generally the best approach. This is often done using laser ablation or a traditional surgical procedure.
It’s important to note that there are some drawbacks to using laser ablation; for example, it can’t be used to study the entire lesion because it ‘burns’ away the tissue. In contrast, a recent study found that when the whole suspicious area was removed and examined, researchers found hidden cancer in 7% of cases and significant abnormal cell changes in 79% of cases. This is why the complete removal and close examination of suspicious areas, or excisional biopsy, is considered the best treatment method in cases of high suspicion.
Interestingly, one study comparing surgical removal to simply quitting smoking and regular monitoring of the lesion found no significant difference in cancer development, suggesting that a ‘wait and watch’ approach might be feasible in low-risk cases.
Non-surgical treatment options such as non-steroidal anti-inflammatory drugs or retinoids (vitamin A-like compounds) may also be effective, but more high-quality research is needed to confirm this. For a specific type of precancerous lesion called lichen planus, topical corticosteroids (a type of anti-inflammation medication applied to the skin) have been used with varying degrees of success.
What else can Premalignant Lesions of the Oral Mucosa be?
There are a number of conditions that can appear similar to oral premalignant lesions. These include:
- Squamous cell carcinoma
- Oral candidiasis (a fungal infection in the mouth)
- Oral hairy leukoplakia (a condition often associated with a weakened immune system)
- Oral mucositis or graft versus host disease (conditions usually linked to radiation therapy or stem cell transplant)
- Autoimmune lesions, such as discoid lupus (a chronic skin condition)
- Kawasaki disease (a rare childhood illness affecting the blood vessels)
The best way doctors can tell these conditions apart is through a biopsy, a test where a small sample of tissue is taken and looked at under a microscope. This test is considered the gold standard in diagnosing these types of conditions.
What to expect with Premalignant Lesions of the Oral Mucosa
The outcome of oral premalignant disorders – which are abnormal changes in the mouth that might turn into cancer – primarily depends on how the sores or lesions look when examined and how severe the abnormal changes are when viewed under a microscope (known as dysplasia).
It is important for these patients to have frequent check-ups, particularly if they have risk factors like tobacco use, a weakened immune system, or severe dysplasia. This is because a recent study found that up to half of patients who have been treated still develop reoccurrence or new sores and as many as one fifth can develop invasive cancer.
In some places, patients at high risk are recommended to have check-ups every three months (quarterly follow-up), while those at lower risk are recommended to have one at least twice a year (biannual follow-up).
Possible Complications When Diagnosed with Premalignant Lesions of the Oral Mucosa
The major concern with pre-cancerous oral conditions is that they may develop into cancer. Recent research found that overall, about 7.9% of all oral pre-cancerous conditions eventually become cancerous. However, the rate varies for specific conditions: lichen planus has a rate of about 1.4%, leukoplakia around 9.5%, oral submucous fibrosis about 5.2%, and erythroplakia approximately 33.1%. Therefore, closely monitoring these conditions and considering surgical procedures to prevent or detect early signs of oral cancer is critical.
Here are the rates at which oral pre-cancerous conditions may become cancerous:
- Lichen planus: 1.4%
- Leukoplakia: 9.5%
- Oral submucous fibrosis: 5.2%
- Erythroplakia: 33.1%
Preventing Premalignant Lesions of the Oral Mucosa
Educating patients about the risks and helping them to avoid tobacco, alcohol, and betel nut exposure is crucial to prevent more damage to the lining of the mouth and prevent conditions that can lead up to cancer. The lining of the mouth (known as the epithelium) can be harmed by these substances, which can lead to disorders that can sometimes turn into cancer.
