Oral Cancer (Mouth Cancer)

Where oral cancer develops

Cancers of the back of the tongue, tonsils and throat are oropharyngeal cancers, which are increasingly caused by HPV. Both are part of the wider group of head and neck cancers.

Early signs and symptoms

• a mouth ulcer or sore that does not heal within 3 weeks
• a white (leukoplakia) or red (erythroplakia) patch on the gums, tongue or lining
• a lump or thickening in the mouth, lip or neck
• persistent mouth pain or a sore tongue
• unexplained bleeding in the mouth
• numbness of the tongue, lip or other area
• loose teeth or poorly fitting dentures
• difficulty chewing, swallowing, speaking or moving the jaw or tongue
• a lump in the neck from spread to lymph nodes
• ear pain on one side without an ear problem
• bad breath and weight loss in later stages

Early oral cancer is often painless, which is why sores and patches that last more than 3 weeks need checking even if they do not hurt.

Causes and risk factors

• Tobacco: cigarettes, cigars, pipes and smokeless tobacco (chewing tobacco, snuff) greatly increase risk.
• Alcohol: heavy drinking, especially combined with tobacco, which multiplies the risk.
• Betel quid and areca nut chewing, common in parts of South and Southeast Asia.
• HPV infection: mainly HPV-16, chiefly linked to oropharyngeal cancer rather than the front of the mouth.
• Sun exposure for lip cancer.
• Age over 50, though rates are rising in younger adults.
• Weakened immune system, including after organ transplant.
• Precancerous lesions: leukoplakia, erythroplakia and oral lichen planus in some cases.
• Poor diet low in fruits and vegetables.
• Rare inherited conditions such as Fanconi anemia and dyskeratosis congenita.

Diagnosis

1. Examination of the mouth, tongue and neck by a dentist or doctor.
2. Biopsy: a small sample of tissue is the only way to confirm cancer.
3. Imaging: CT, MRI and PET scans to see the size of the tumor and spread to lymph nodes or other areas.
4. Endoscopy of the throat and voice box to look for other cancers.
5. HPV testing of the tumor for oropharyngeal cancers.
6. Dental assessment before treatment, especially radiation.

Stages

Oral cancer is staged with the TNM system: tumor size and depth of invasion (T), lymph node spread (N) and distant spread (M), giving stages I to IV.

• Stage I and II: small tumors without lymph node spread; high cure rates with surgery.
• Stage III and IV: larger tumors, lymph node or distant spread; need combined treatment.

Five-year survival is high, roughly 85 percent or more, when cancer is localized, and falls when it has spread, which is why early detection matters.

Treatment

Treatment is planned by a head and neck cancer team.

• Surgery: removing the tumor with a margin of healthy tissue, often with removal of neck lymph nodes (neck dissection). Reconstructive surgery uses tissue from elsewhere in the body to restore function and appearance.
• Radiation therapy: after surgery for higher-risk tumors, or as main treatment in some cases.
• Chemotherapy: combined with radiation (chemoradiation) for advanced disease.
• Immunotherapy and targeted therapy: pembrolizumab, nivolumab and cetuximab for recurrent or metastatic cancer.

Rehabilitation

Speech and swallowing therapy, nutrition support, dental care and prosthetics help recovery. Side effects of radiation can include dry mouth, mouth sores, taste changes, tooth decay and jaw bone problems.

Prevention and early detection

• Do not use tobacco in any form; quitting reduces risk over time.
• Limit alcohol.
• Avoid betel quid and areca nut.
• Get the HPV vaccine (recommended at ages 11 to 12, and through age 26; some adults 27 to 45 after discussion).
• Use lip balm with sunscreen.
• Eat plenty of fruits and vegetables.
• See a dentist regularly; dentists check for oral cancer during exams.
• Check your mouth monthly and report sores or patches lasting more than 3 weeks.

Frequently asked questions

What are the early signs of oral cancer?

Early signs include a mouth sore or ulcer that does not heal within 3 weeks, white or red patches, a lump or thickening, unexplained bleeding or numbness, loose teeth and difficulty chewing or swallowing. Early oral cancer is often painless.

What does oral cancer look like?

It may look like a non-healing ulcer with raised or hard edges, a white or red patch, a rough lump or a thickened area, most often on the sides of the tongue or the floor of the mouth. Only a biopsy can confirm whether an area is cancer.

What causes oral cancer?

The biggest causes are tobacco in any form and heavy alcohol use, especially together. Betel quid chewing, sun exposure (for lip cancer) and HPV infection (mainly for cancers at the back of the throat) are other important causes.

Is oral cancer curable?

Yes, especially when found early. Small oral cancers have high cure rates with surgery alone. Advanced cancers need combined treatment and have lower cure rates, but many people still do well. Regular dental checks help catch it early.

How long can a mouth ulcer last before it is a concern?

Most ordinary mouth ulcers heal within 1 to 2 weeks. Any ulcer, sore, lump or patch that lasts longer than 3 weeks should be checked by a dentist or doctor, particularly if you smoke or drink heavily.