Oral Cancer — Symptoms, Causes & Treatment | MyMedicPlus

Oral cancer most commonly refers to squamous cell carcinoma (SCC) arising from the squamous epithelial mucosa of the oral cavity — including the lips, tongue (most common site, accounting for 30–40%), floor of mouth, buccal mucosa, hard palate, retromolar trigone, and alveolar ridge. SCC accounts for over 90% of oral cavity malignancies. Oropharyngeal SCC (tonsil, base of tongue, soft palate) is closely related but increasingly HPV-driven and classified separately from oral cavity SCC. Globally, approximately 380,000 new cases of oral and lip cancer occur each year, making it the 6th most common cancer worldwide; incidence is highest in South and South-East Asia (betel quid chewing) and parts of Eastern Europe. In the UK, over 8,800 new cases of oral cancer are diagnosed annually with approximately 2,700 deaths. 5-year survival is approximately 60–70% for localised (Stage I-II) disease but drops to 30–40% with regional lymph node involvement and below 20% with distant metastases — reflecting the critical importance of early diagnosis. Oral cancer disproportionately affects men (2:1 male-to-female ratio) and is most common in those above age 55, though HPV-related cases in younger individuals are increasing.

Major risk factors: tobacco (smoking — relative risk 5–7x; smokeless tobacco — chewing tobacco, snuff; betel quid — a major cause in India, Sri Lanka, and South-East Asia where oral cancer incidence is highest globally) and alcohol (relative risk 3–9x — synergistic with tobacco, multiplying risk by 30–50x when both are used heavily). Human papillomavirus (HPV-16 and HPV-18): causes approximately 25% of oral cavity cancers and over 70% of oropharyngeal (tonsil, base of tongue) cancers in developed countries — HPV-positive oropharyngeal cancers carry a significantly better prognosis (5-year survival 80–90%) than HPV-negative (40–60%) and affect younger, non-smoking individuals. Chronic mucosal trauma: ill-fitting dentures causing chronic ulceration, poor dental hygiene (plaque, periodontal disease), and prolonged mucosal irritation promote carcinogenesis. Nutritional deficiencies: iron, vitamins A and C, and folate deficiency are associated, particularly in populations with dietary inadequacy. Premalignant lesions require surveillance: leukoplakia (white patch — malignant transformation rate 1–17% over 10 years; homogeneous leukoplakia lower risk; non-homogeneous higher risk) and erythroplakia (red patch — malignant potential 17–51%, the highest of all oral premalignant lesions). Oral lichen planus (erosive subtype): malignant transformation rate approximately 1–2% lifetime risk. Immunosuppression (organ transplant recipients, HIV) increases risk. Prior head and neck radiotherapy.

The most important warning sign is a non-healing ulcer or red/white patch in the mouth persisting more than 3 weeks — this must be assessed by a dentist or doctor and biopsied if suspicious; most mouth ulcers are benign aphthous ulcers that heal within 7–14 days. Persistent swelling, lump, or indurated (hard) thickening of the cheek, tongue, floor of mouth, or oral mucosa. Difficulty swallowing (dysphagia) or chewing, or trismus (limited mouth opening — indicates involvement of the pterygoid muscles by tumour; a poor prognostic sign). Persistent pain in the mouth, jaw, teeth, or referred pain to the ear (otalgia — even with normal ear examination; caused by cranial nerve V3/IX/X involvement). Unexplained bleeding from the mouth not related to gum disease or trauma. Loose teeth not explained by periodontal disease — underlying alveolar bone invasion by tumour. Cervical lymphadenopathy (painless neck lump — may be the first presenting feature when the primary lesion is small; a firm, non-tender lymph node in the neck of a tobacco or alcohol user over 40 must be investigated urgently). Persistent hoarseness or voice change (oropharyngeal or laryngeal extension). Numbness or altered sensation of the lip or chin (inferior alveolar nerve involvement by mandibular cancer or metastatic node). Early-stage oral cancer may be entirely asymptomatic and painless — underlining the importance of regular oral cancer screening during dental check-ups.

Biopsy of the suspicious lesion with histopathological examination (H&E staining + immunohistochemistry including p16 for HPV surrogate marker) is required for definitive diagnosis — incisional biopsy from the most abnormal-appearing area; punch biopsy is an alternative for accessible lesions. Fine needle aspiration cytology (FNAC) or core needle biopsy of a suspicious neck node — avoids open biopsy which disrupts lymph node architecture. Imaging (staging after biopsy confirmation): CT of the head and neck (with IV contrast) assesses primary tumour extent, cortical bone invasion (mandible and maxilla involvement alters operability), and lymph node status (enlarged nodes above 1 cm, necrotic, or with extranodal extension indicate metastatic involvement); MRI of the head and neck — superior to CT for soft tissue invasion (floor of mouth, tongue base, perineural invasion); FDG-PET-CT — whole-body staging, detects occult nodal metastases and distant metastases in the lungs, liver, and bone; indispensable for high-risk T3/T4 lesions and before definitive chemoradiotherapy. HPV testing (p16 IHC immunohistochemistry — a surrogate marker for HPV-16/18) is performed on all oropharyngeal SCC to guide prognosis and potential treatment de-intensification strategies. Panendoscopy (rigid laryngoscopy, oesophagoscopy, bronchoscopy) under general anaesthesia: examines the entire aerodigestive tract for synchronous second primary tumours — present in 3–5% of tobacco/alcohol-related cases. TNM staging (AJCC 8th edition) defines treatment intent and prognosis.

Early-stage (T1-T2 N0): surgery with adequate margins (minimum 5 mm clear histological margin) is the preferred treatment for oral cavity SCC, providing equivalent oncological outcomes to radiotherapy while preserving the option of future irradiation for recurrence; elective ipsilateral selective neck dissection is performed routinely for tongue and floor-of-mouth tumours due to a 20-30% occult nodal metastasis rate even with clinically node-negative necks. Advanced-stage (T3-T4 or node-positive): combined surgery (wide local excision plus selective or modified radical neck dissection) with adjuvant radiotherapy (60-66 Gy over 6 weeks); adjuvant concurrent platinum-based chemoradiotherapy (cisplatin 100 mg/m2 every 3 weeks with radiotherapy 63-70 Gy) is indicated for high-risk histopathological features including positive or close margins (below 5 mm), perineural invasion, lymphovascular invasion, and extranodal extension (ENE). Inoperable disease: definitive concurrent chemoradiotherapy with cisplatin or carboplatin (for patients with contraindications to cisplatin — renal impairment, hearing loss, neuropathy). Recurrent or metastatic disease: pembrolizumab (anti-PD-1 immunotherapy) as first-line monotherapy for PD-L1 positive HNSCC (CPS score above 1); or pembrolizumab plus platinum-fluorouracil chemotherapy; cetuximab (anti-EGFR monoclonal antibody) plus platinum-fluorouracil as an alternative. Microvascular free flap reconstruction (radial forearm fasciocutaneous, fibular osteocutaneous, anterolateral thigh) restores form and function after major resections — speech therapy, swallowing rehabilitation, and pre-treatment dental extraction are integral components of multidisciplinary team care.

Oral cancer and its treatment cause significant functional and psychological complications. Functional complications of surgery: wide surgical excision of the tongue, floor of mouth, or mandible causes dysphagia (difficulty swallowing — aspiration pneumonia risk), dysarthria (speech impairment), trismus (jaw stiffness from fibrosis), xerostomia (dry mouth from salivary gland removal), and facial disfigurement. Microvascular free flap reconstruction (radial forearm, fibular, anterolateral thigh) partially restores form and function, but speech therapy and swallowing rehabilitation are required after major resections. Radiotherapy complications: acute mucositis (radiation-induced ulceration of the oral mucosa — severe pain, dysphagia, weight loss requiring nasogastric or PEG feeding during treatment), xerostomia (permanent dry mouth from salivary gland damage — increases dental decay and dysphagia), osteoradionecrosis (radiation-induced bone death of the mandible or maxilla — affects 5–15% — causes chronic exposed bone, pain, and pathological fracture), dysphagia, trismus, and hypothyroidism (from neck irradiation). Chemotherapy complications: cisplatin nephrotoxicity (requires IV hydration and dose adjustment in renal impairment), ototoxicity (cisplatin-induced sensorineural hearing loss), peripheral neuropathy, myelosuppression, and nausea. Locoregional recurrence: the most significant oncological complication — approximately 40–50% of locally advanced oral cancers recur within 2 years despite optimal treatment; salvage surgery carries substantially higher morbidity and lower cure rates. Second primary cancers: tobacco and alcohol users have a 3–7% annual risk of synchronous or metachronous second primaries in the aerodigestive tract (lung, oesophagus, larynx). Psychological impact: depression, anxiety, body image concerns, and social withdrawal are common in oral cancer survivors — multidisciplinary psychosocial support is integral to survivorship care.

Seek urgent (2-week-wait cancer pathway) referral to an oral and maxillofacial surgeon or head and neck oncology service for: any oral ulcer not healing within 3 weeks; a white patch (leukoplakia), red patch (erythroplakia), or mixed red-white patch on the oral mucosa; a painless lump in the mouth, lips, tongue, or neck; difficulty swallowing or persistent hoarseness lasting over 3 weeks; unexplained jaw trismus (limited mouth opening); or a lump in the neck in a person who uses tobacco or alcohol. All these features require histological assessment to exclude oral cancer — early-stage oral cancer has a cure rate of over 80%, while late-stage disease has a 5-year survival of approximately 30-40%. Do not delay dental or medical review for any mouth lesion that does not heal normally within 3 weeks. High-risk individuals (tobacco users, heavy alcohol drinkers, HPV infection, oral lichen planus) should have annual oral cancer screening by a dentist or physician — inspection and palpation of the oral mucosa, tongue, floor of mouth, and neck.

Tobacco cessation reduces oral cancer risk substantially — the risk approaches that of non-smokers within 10–15 years of quitting; smoking cessation services (varenicline, NRT, bupropion) are recommended for all tobacco users. Limit alcohol consumption (below 14 units per week for both men and women — UK low-risk guidelines). HPV vaccination (Gardasil 9 — protects against HPV types 6, 11, 16, 18, 31, 33, 45, 52, 58): reduces oropharyngeal cancer risk substantially; recommended for males and females ages 9–26 in the USA; NHS UK programme offers vaccination to all children aged 12–13 (Year 8). Regular dental check-ups (6-monthly) allow early detection of mucosal changes — dentists are the primary screeners for oral cancer and should perform systematic oral mucosal inspection at each visit. Self-examination of the oral cavity monthly using a torch and mirror — inspect the tongue (including sides and undersurface), floor of mouth, cheeks, palate, and lips for persistent ulcers, lumps, or colour changes. Manage premalignant lesions (leukoplakia, erythroplakia) with specialist oral medicine or oral maxillofacial surgery surveillance, photodynamic therapy, or excision where appropriate. Optimal nutrition with adequate fruit and vegetable intake reduces mucosal oxidative damage. Betel quid cessation is a major preventive priority in South and South-East Asian populations.