Oral cancer

Disease Description (Causes and Symptoms)

• Definition: Oral cancer is a malignant tumor that develops in the oral mucosa, including the lips, tongue, gums, front part of the roof of the mouth (hard palate), and inner cheeks. Most cases are squamous cell carcinomas.
• Main causes and pathophysiology: Long-term smoking and excessive alcohol consumption are the greatest risk factors (the risk increases when both factors are present), and contributing factors include poor oral hygiene, vitamin deficiency, chronic mucosal injury (e.g., sharp teeth or ill-fitting dentures), and, in the case of the lips, ultraviolet exposure. Some head and neck cancers (especially oropharyngeal cancers) may be associated with HPV infection; however, smoking and alcohol consumption are considered the main factors in squamous cell carcinoma of the oral mucosa. Cancer cells can destroy local tissue, invade adjacent bone tissue (the jawbone), or metastasize to the cervical lymph nodes. As the disease progresses, distant metastases to the lungs, liver, bones, and other sites may occur.
• Main symptoms: A non-healing ulcer or lump in the mouth, persistent pain, white or red patches on the oral surface, difficulty chewing or swallowing, restricted movement of the tongue or jaw, sensory abnormalities, loose teeth, jaw swelling or enlarged cervical lymph nodes, unexplained weight loss, and other symptoms. Evaluation is needed if symptoms persist for more than 2 weeks.

Treatment Methods

• The treatment plan is determined according to the stage (stages 0–4) after diagnosis. A biopsy is used to confirm the diagnosis, CT/MRI is used to evaluate local invasion, bone invasion, and surrounding soft tissue, and PET-CT or, when necessary, a bone scan is used to evaluate metastasis.
• Surgery: This is the basic treatment for oral cancer and involves removing the tumor and the surrounding tissue affected by it. If spread to the cervical lymph nodes is suspected or for preventive purposes, neck dissection (removal of lymph nodes in the neck) is performed. After resection, the defect is reconstructed using methods such as a free flap with microvascular anastomosis (tissue transferred from the arm, leg, or chest) to preserve form and function (speech, chewing, and swallowing) as much as possible.
• Radiation therapy: This is used as adjuvant treatment after surgery to reduce residual risks (lymph node metastasis, close surgical margins, etc.), or as standalone treatment or combined chemoradiation when surgery is not possible or to relieve symptoms. Radiation may cause dry mouth (xerostomia) due to salivary gland damage and carries a risk of osteonecrosis, so dental evaluation is needed before and after treatment.
• Chemotherapy (systemic therapy): This is used to shrink the tumor before surgery (induction therapy), as adjuvant therapy after surgery or radiation, or to control symptoms in advanced or metastatic disease. Cisplatin and 5‑FU, as well as targeted drugs (e.g., cetuximab), are commonly used. Immunotherapy drugs (e.g., pembrolizumab and nivolumab) may be indicated for patients with recurrent or metastatic disease (according to the latest guidelines).
• Rehabilitation and supportive care: Speech and swallowing rehabilitation (speech therapy), nutritional management (including tube feeding when necessary), dental care (dental treatment and management of extractions before radiation), and treatment of pain and dry-mouth symptoms (such as artificial saliva).
• Complication management and precautions: Postoperative bleeding and infection, dry mouth, soft-tissue fibrosis, and osteonecrosis after radiation (especially of the mandible), and systemic side effects related to anticancer treatment (bone marrow suppression, nausea, etc.). Before radiation therapy, dental examination should be performed, with treatment of cavities and extractions when necessary. After radiation therapy, it is important to avoid dental surgery.

Checkpoints Before an Outpatient Visit (Including Preparation and Sample Questions)

What to Bring

• A list of all medications currently being taken (including prescription drugs, OTC medications, herbal medicines, and supplements), along with the times and doses taken
• Previous medical certificates, biopsy results (pathology reports), or examination CDs/imaging reports (CT, MRI, PET, etc.)
• When symptoms began and how they have progressed (lesion photographs, if available)
• Smoking and alcohol consumption history (duration and amount per day), and whether there has been occupational exposure to sunlight
• Previous dental treatment history and whether dentures are worn
• History of allergies (medications and food)

Items to Tell the Doctor First During the Visit (Examples)

• When symptoms began (how many weeks or months ago), factors that worsen them, and factors that improve them
• Whether acute symptoms such as bleeding, severe pain, weight loss, or difficulty breathing are present
• A history of recent radiation or anticancer treatment

Preparation Before Testing

• The possibility of a biopsy for diagnosis and whether imaging tests (CT/MRI/PET) need to be scheduled
• If radiation therapy may be needed, the need for a preliminary dental evaluation

General Sample Questions to Ask the Doctor

• What is the exact stage of this disease? What is the treatment goal (cure versus symptom relief)?
• What treatment options do you recommend, and what are the advantages and disadvantages of each treatment (complications and expected functional preservation)?
• If surgery is needed, what reconstruction method will be used, and what is the expected recovery period?
• What are the side effects of radiation and anticancer treatment, and what measures can be taken beforehand to reduce them?
• What will the follow-up examination schedule be after treatment? What treatment options are available if the disease recurs?

Disease-Specific Sample Questions

• Is cervical lymph node metastasis suspected in my lesion? Do I need preventive neck dissection?
• After surgical resection, what rehabilitation (speech therapy and nutritional therapy) is needed to restore speech and swallowing function, and when should it begin?
• If I need radiation therapy, what dental measures (extractions and cavity treatment) should be completed first to reduce the risk of radiation-induced dry mouth and mandibular osteonecrosis?

Brief Prevention Recommendations

• Smoking cessation and moderation of alcohol consumption (particularly avoiding the combination of the two), regular dental checkups and oral hygiene care, adjustment of dentures and sharp teeth by a dentist, and protection from ultraviolet radiation in the case of lip cancer (a wide-brimmed hat and sunscreen) are recommended.