What is oral cancer? Symptoms and treatment

The simplest definition of cancer is the continuous, uncontrolled multiplication of cancer cells. Since every tissue and organ in our bodies consists of cells, it is understandable that there can be nearly 150 types of cancer. Our mouths can also be affected by this uncontrolled multiplication, which can occur in almost any tissue or organ.

- Related topic: What is metastasis? Symptoms of metastasis, and why cancer metastasizes

Oral cancer is a head and neck cancer type; in medicine, it is called oral cancer. Oral cancers have no specific location within the mouth and can occur anywhere in the mouth and lips, including tissues in the tongue and gums, as well as the tissues inside the cheeks. Although they occur on the lips, tongue, lining of the tongue, inside the cheeks, hard palate (the bony roof of the mouth), and floor of the mouth beneath the tongue, research indicates that the most common sites are:

• Tongue
• Tonsils
• Floor of the mouth
• The soft palate at the back of the mouth (oropharynx).

What are the symptoms of oral cancer?

Since everyone's body is different, the appearance of oral cancer will also vary from person to person.

The main symptoms of oral cancer are:

• Rough white or red patches of tissue
• Tissues that turn gray or white
• Sores/ulcers on the tongue that do not go away over time
• Shiny patches on the tongue
• A lump inside the mouth or a mass near the front teeth

Although these early symptoms are often confused with another condition, or there may be no symptoms in the initial stage of cancer, it becomes more apparent at a later stage with the following symptoms:

• Bleeding and pain in the mouth
• Numbness in some areas of the mouth
• Sore throat
• Loose teeth
• Red or white patches in and around the mouth
• A gap in chewing and swallowing 

Noticing a patch or thickened tissue in the skin-like squamous (flat) cells covering the surface of the mouth, tongue, and lips is also an important sign requiring immediate medical attention.

We use the term dysplasia to describe abnormal cell development in humans. In adults, this means precancer (a structure that has not yet become cancer but will develop into it). Oral cancer may also include certain precancers such as leukoplakia, erythroplakia, and erythroleukoplakia. Although leukoplakia is described as white or gray sores inside the mouth that do not disappear when rubbed, it is actually considered the least harmful because most cases do not become cancer. Erythroplakia appears as flat or raised tissue that can bleed immediately when scratched. Unfortunately, most lesions of this type and of erythroleukoplakia, which combines the two, become cancer. It should also be remembered that cancerous lesions never, ever go away over time.

Painful white lesions inside the mouth, lichen planus, also known as chronic inflammation in the mouth, cause white lacy patches that do not resemble leukoplakia cells. Although debate about its relationship with cancer continues, it is thought to increase the risk of lip, tongue, esophageal, oral cavity, and laryngeal cancer in affected people. Benign tumors may also be argued to pose a danger because of frequent cell division.

Even if we associate the symptoms with other conditions, we cannot ignore oral cancer. Even routine dental checkups are an important step for oral cancer. Difficulty with activities such as chewing, swallowing, and breathing requires immediate medical attention. Even if you do not have oral cancer, all these symptoms show that something is wrong. Early diagnosis always improves treatment success under all circumstances and can also save lives in severe cases.

How are oral cancers treated?

The treatment regimen chosen by your medical oncologist will depend on the stage and location of the cancer. It would be wise to discuss all options relating to your condition.

Surgery

The surgical removal of oral cancers is primarily handled by ENT surgeons and, in some cases, plastic surgeons. Surgery is generally the first method of treating oral cancer and is most commonly used for "early-stage" oral cancers. During surgery to remove the cancer, lymph nodes in the neck may also be removed because oral cancers commonly spread there.

- Related topic: Cancer Operations – Oncological Surgery

Radiation therapy

Radiation therapy uses certain types of high-energy radiation beams to shrink tumors or eliminate cancer cells. Radiotherapy works by damaging a cancer cell's DNA and preventing it from multiplying.

Chemotherapy

Instead of surgery, some oral cancers may be treated with chemotherapy, usually given together with radiation therapy and called chemoradiotherapy. It may be given before surgery to reduce the size of a cancer (called neoadjuvant chemotherapy), or together with radiation after surgery to eliminate remaining cancer cells (called adjuvant chemoradiation). For advanced oral cancers, chemotherapy can be used to slow tumor growth, relieve symptoms and complaints, and prolong life. 

Targeted therapy

The targeted treatment used for oral cancer is called Erbitux (cetuximab) and works by suppressing a protein found on cancer cells called epidermal growth factor (EGFR). This protein helps cancer cells grow and replicate, so blocking it can stop cancer growth. Depending on the cancer stage, cetuximab may be combined with radiation or chemotherapy, or even used as a single agent.

- Related topic: What Is Targeted Therapy in Cancer? All FDA-approved targeted drugs

Immunotherapy and the treatment of advanced (metastatic) oral cancers

Oral cancers have a high risk of regional recurrence. Recurrent and metastatic disease accounts for around 65% of head and neck cancers. In metastatic disease, chemotherapy, immunotherapy, and/or supportive care are the most appropriate options. Immunotherapy may produce long-term responses in some patients.

Before immunotherapies, median survival for this patient group was around 10 months; with immunotherapies, we know that this has increased to around 15 months.

The historical development of systemic treatment for HNC has been as follows:

The most commonly used drugs for head and neck cancers are platinum compounds (cisplatin, carboplatin), taxanes (docetaxel, paclitaxel, nanoparticle albumin-bound paclitaxel), 5-FU, methotrexate, the anti-EGFR agent cetuximab, and anti-PD-1 checkpoint immunotherapies[pembrolizumab (Keytruda) and nivolumab (Opdivo)].

For patients with recurrent or metastatic head and neck cancer, standard first-line systemic treatment was platinum-based chemotherapy (cisplatin or carboplatin with 5-FU) plus the EGFR inhibitor cetuximab, based on the EXTREME study whose results were published in 2008. Through the KEYNOTE-048 study in 2019, pembrolizumab obtained approval for treating PD-L1-positive patients with recurrent or metastatic head and neck cancer from the FDA.