Oral Cancer — Causes, Symptoms & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Oral cancer encompasses malignant tumours arising in the oral cavity (lips, tongue, floor of mouth, buccal mucosa, hard palate, gingiva, and retromolar trigone) and oropharynx (soft palate, base of tongue, tonsillar pillars, pharyngeal walls). Over 377,000 new oral cancer cases are diagnosed globally each year, causing approximately 177,000 deaths. Squamous cell carcinoma (SCC) accounts for over 90% of oral cancers — arising from the stratified squamous epithelium lining the oral cavity. The incidence varies markedly by region: highest in South and Southeast Asia (India, Sri Lanka, Bangladesh) due to widespread use of tobacco and areca nut (betel nut). Early-stage (Stage I-II) oral cancer has a 5-year survival rate above 80%; late-stage (Stage III-IV) drops to below 30% — making early detection critical.

Tobacco use (all forms) is the most important risk factor for oral cavity SCC — smoking (cigarettes, cigars, pipes), smokeless tobacco (chewing tobacco, snuff), and tobacco-containing betel quid account for approximately 50% of oral cancer cases. Alcohol misuse: a strong independent risk factor — heavy alcohol use (more than 21 units/week) doubles risk; the combination of tobacco and alcohol has a synergistic effect (multiplying rather than simply adding risks) and accounts for 75% of oral cavity cancers. Areca nut (betel nut) and betel quid chewing: major cause in Asia — causes oral submucous fibrosis (a precancerous condition) and directly increases SCC risk; affects 600 million users globally. Human Papillomavirus (HPV) — specifically HPV-16 and HPV-18 — is the dominant cause of oropharyngeal SCC (base of tongue, tonsils) — rising rapidly in Western countries, particularly in non-smoking younger men. Sun exposure (UV radiation) causes lip cancer. Chronic oral trauma from ill-fitting dentures, broken teeth, or sharp dental restorations. Immunosuppression (organ transplant recipients, HIV). Previous head and neck radiation.

Early oral cancer is frequently asymptomatic — detected only on routine dental examination. Symptoms and warning signs: a persistent oral ulcer that fails to heal within 3 weeks (most important red flag), a red patch (erythroplakia — high malignant transformation rate), a white patch (leukoplakia), or a red-and-white patch (erythroleukoplakia) in the mouth that cannot be wiped off. Unexplained persistent swelling, lump, or thickening in the oral mucosa or lips. Unexplained tooth loosening or jaw stiffness. Difficulty chewing, swallowing (dysphagia), or speaking. Referred otalgia (ear pain in the absence of ear disease — via cranial nerve VII or IX from the oropharynx). Persistent blood in saliva. A painless neck lump (cervical lymphadenopathy from nodal metastasis — often the presenting feature of oropharyngeal SCC). Trismus (restricted mouth opening) indicates advanced disease with pterygoid muscle involvement. Weight loss and odynophagia (painful swallowing) indicate advanced disease.

Clinical examination of the entire oral cavity and oropharynx — including bimanual palpation of the floor of mouth and tongue, and palpation of cervical lymph nodes — under good lighting by a dental surgeon or ENT specialist. Incisional biopsy of the suspicious lesion is essential for histopathological diagnosis — all non-healing oral ulcers or suspicious mucosal changes should be biopsied after 3 weeks if no cause identified and no response to treatment. Punch biopsy of accessible lesions. Panendoscopy (laryngoscopy, bronchoscopy, oesophagoscopy) under general anaesthesia for oropharyngeal and posterior lesions, and to assess extent and synchronous primary tumours. CT neck with contrast (staging of primary tumour and regional lymph nodes). MRI with contrast: superior soft tissue assessment — bone, nerve, and muscle involvement; tongue base lesions. PET-CT scan: detects occult distant metastases and guides management of unknown primary. HPV testing (p16 immunohistochemistry) on oropharyngeal SCC biopsy — determines prognosis and increasingly guides treatment intensity. Staging by AJCC TNM classification determines treatment planning.

Early stage oral cavity SCC (Stage I-II): Wide local excision with adequate histological margins (minimum 5mm clear) plus selective neck dissection (elective treatment of regional lymph nodes) — cure rates of 80-90%. Reconstruction: primary closure, local flaps, radial forearm free flap (RFFF), fibula osteocutaneous free flap for mandibular reconstruction. Adjuvant radiotherapy if adverse histological features (positive/close margins, perineural invasion, lymphovascular invasion, multiple lymph node metastases). Advanced oral cavity SCC (Stage III-IV): multimodal therapy — surgery + adjuvant cisplatin-based chemoradiotherapy for high-risk features. Concurrent cisplatin + radiotherapy (70Gy in 35 fractions) for unresectable disease or organ-preservation strategy. Oropharyngeal SCC: HPV-positive oropharyngeal cancer has a significantly better prognosis — primary chemoradiotherapy (cisplatin + IMRT) achieving excellent oncological outcomes. Transoral Robotic Surgery (TORS) for selected oropharyngeal tumours — minimally invasive with rapid recovery. Recurrent/metastatic disease: cetuximab (anti-EGFR), pembrolizumab (anti-PD-1 immunotherapy) — KEYNOTE-048 established pembrolizumab as first-line for recurrent/metastatic HNSCC. Rehabilitation: speech therapy, swallowing rehabilitation, dental prosthetics, and jaw physiotherapy are essential after treatment.

Oral cancer causes serious and frequently permanent complications from both the cancer itself and from curative treatment. Treatment-related complications: radiation therapy complications include xerostomia (dry mouth — from salivary gland damage; permanent in 60-90% receiving radiation to the head and neck); radiation-induced trismus (reduced mouth opening from fibrosis of masticatory muscles — progressive and limits nutrition and dental access); osteoradionecrosis of the jaw (avascular necrosis of mandible or maxilla from radiation-induced hypoxia — occurring in 5-10% of head and neck radiation; may require major jaw surgery); lymphoedema of the face and neck from surgical lymph node dissection. Surgery complications: radical neck dissection causes shoulder dysfunction from accessory nerve damage (30-40% permanent shoulder weakness); major reconstructive surgery (free flap reconstruction — fibula, forearm) carries significant complications; permanent disfigurement affects body image and social function. Functional complications: dysphagia (difficulty swallowing — from tumour involvement of the tongue, floor of mouth, oropharynx — or post-treatment fibrosis) affects nutrition and requires feeding tube dependence in up to 20%; dysarthria (impaired speech) from tongue and palate involvement; chronic pain from nerve involvement. Recurrence and second primary cancers: local recurrence occurs in 20-40% within 2 years — typically carries poor prognosis; field cancerisation — shared tobacco/alcohol exposure to the entire upper aerodigestive tract — increases second primary cancer risk in pharynx, larynx, oesophagus, and lung.

Tobacco cessation is the single most impactful prevention measure — eliminates the major modifiable risk factor; cessation resources include NRT, varenicline, bupropion, and behavioural support. Limit alcohol to low-risk levels (under 14 units/week); avoid co-use of tobacco and alcohol. Avoid betel nut/areca nut and betel quid in all forms. HPV vaccination (Gardasil 9 — 9-valent) in adolescents before sexual exposure reduces HPV-16 and HPV-18 infection — expected to reduce HPV-associated oropharyngeal cancer rates in coming decades. Regular dental check-ups (every 6-12 months) with full oral mucosal examination — dentists are frontline for early oral cancer detection. Sun protection (SPF 30+ lip balm, hat) reduces lip cancer. Self-examination of the oral cavity monthly — check tongue, floor of mouth, cheeks, gums and palate for any persistent sores or changes. Report any non-healing oral sore lasting more than 3 weeks to a dentist or doctor.

See a dentist or doctor promptly — within 2 weeks — for any oral ulcer or sore that has not healed after 3 weeks, any red or white patch in the mouth that cannot be wiped off, a lump or thickening inside the mouth or on the lips, unexplained difficulty swallowing or speaking, persistent hoarseness, or a painless neck lump. Do not delay assessment waiting for the lesion to heal on its own — early oral cancer is often asymptomatic and painless. Dentists detect the majority of early oral cancers during routine check-ups. High-risk individuals (tobacco users, heavy alcohol drinkers, betel nut users) should have an annual oral mucosal examination. If a biopsy is recommended, do not delay — oral cancer caught at Stage I has an 80%+ survival rate, while Stage IV disease has under 30% survival.