Oral Squamous Cell Carcinoma (Mouth Cancer)

What oral squamous cell carcinoma is

The inside of the mouth is lined with squamous epithelium. Repeated damage, mainly from tobacco and alcohol, causes genetic changes in these cells. Many cancers develop from potentially malignant disorders: leukoplakia (white patches), erythroplakia (red patches, the most concerning) and oral submucous fibrosis. Over months to years, abnormal cells (dysplasia) can progress to invasive cancer, which can spread to lymph nodes in the neck.

Oral cavity cancer is one type of head and neck cancer. It is different from oropharyngeal cancer (tonsils and base of tongue), which is now often caused by HPV.

Risk factors

• Tobacco: cigarettes, cigars, pipes and smokeless tobacco (chew, snuff)
• Alcohol: risk multiplies when combined with tobacco
• Betel quid and areca nut chewing: a major cause in South and Southeast Asia
• Sun exposure: lip cancer
• Older age: most cases over 55
• Male sex, though rates in women are rising
• Weakened immunity, including after organ transplant
• Oral lichen planus (small increased risk)
• Fanconi anemia and dyskeratosis congenita
• possibly poor oral hygiene and chronic irritation from sharp teeth or dentures

A growing share of tongue cancers occur in younger people without these risk factors, for reasons not yet understood.

Symptoms

• a mouth ulcer that does not heal within 3 weeks
• a white patch (leukoplakia) or red patch that does not rub off
• a lump, thickening or rough area
• pain or tenderness in the mouth, tongue or ear
• bleeding
• numbness of the tongue, lip or chin
• loose teeth, or dentures that no longer fit
• difficulty chewing, swallowing, speaking or moving the tongue
• a lump in the neck (swollen lymph nodes from spread)
• weight loss in advanced disease

Early cancers are often painless, which is why regular dental exams matter.

Diagnosis

• Examination by a dentist, oral surgeon or ENT specialist, including feeling the neck
• Biopsy of the suspicious area, the only way to confirm cancer
• Imaging for staging: CT and/or MRI of the head and neck, PET-CT for advanced disease, chest imaging
• Endoscopy to check the throat and esophagus for second cancers

Staging

Staging uses the TNM system: tumor size and depth of invasion (T), spread to neck lymph nodes (N), and distant spread (M). Stages I and II are small cancers without node spread; stages III and IV are larger or have spread to nodes or beyond.

Treatment

Treatment is planned by a multidisciplinary head and neck cancer team.

Surgery

• Removal of the tumor with a margin of healthy tissue
• Neck dissection: removing lymph nodes, either because cancer is present or as a precaution for deeper tumors
• Reconstruction: using local tissue or free flaps from the arm, leg or back to restore speech and swallowing

Radiation and chemotherapy

• Radiation therapy after surgery for higher-risk cancers (larger tumors, positive nodes, close margins)
• Chemoradiation (radiation with cisplatin) when there are high-risk features such as cancer spreading outside lymph nodes or positive margins
• Immunotherapy (pembrolizumab, nivolumab) for recurrent or metastatic disease

Rehabilitation

Speech and swallowing therapy, dental care (including before radiation), nutrition support, and management of dry mouth and jaw stiffness.

Outlook

Outlook depends mainly on stage at diagnosis. Small, localized oral cancers have 5-year survival rates of around 85%. Survival falls when cancer has spread to lymph nodes or beyond. Stopping smoking and drinking improves treatment results and lowers the risk of a second cancer. Regular follow-up is needed for at least 5 years.

Prevention and early detection

• stop smoking and avoid all tobacco and betel quid
• limit alcohol
• use lip balm with sunscreen
• have regular dental checkups, which include an oral cancer screening
• check your own mouth monthly and report any sore or patch lasting more than 3 weeks
• HPV vaccination prevents HPV-related oropharyngeal cancers

Frequently asked questions

What are the early signs of mouth cancer?

The most common early signs are a mouth ulcer that does not heal within 3 weeks, a red or white patch, or a lump or thickening in the mouth. Early cancers are often painless. Any persistent change should be checked by a dentist or doctor.

What does oral squamous cell carcinoma look like?

It can look like a non-healing ulcer with raised, firm edges, a white or red patch, a speckled red-white area, or a lump. It is most common on the sides of the tongue and the floor of the mouth. A biopsy is needed to diagnose it.

Is oral cancer curable?

Yes, especially when found early. Small cancers are often cured with surgery alone. Advanced cancers need combined treatment, and cure rates are lower. Early detection through dental checkups and self-examination improves the outlook.

Can you get mouth cancer without smoking?

Yes. Although tobacco and alcohol are the main risk factors, oral cancer also occurs in people who have never smoked, including younger adults with tongue cancer. Any persistent mouth sore or patch should be checked regardless of risk factors.