Epidemiology and Etiology
- Oral (mouth) cancer accounts for most head and neck cancers.
- The majority is squamous cell carcinoma (SCC).
- Peak incidence is in the 6th decade of life.
- Men > women by a 2:1 ratio
- Common in certain countries: Bangladesh, Sri Lanka, India, and Pakistan
- Tobacco chewing/smoking
- HPV infection
- Chronic mechanical irritation (badly positioned dentures)
- Low intake of fruits and vegetables
- Betel quid chewing (contains areca nut)
- Presence of precancerous lesions:
- Erythroplakia (red plaque)
- Leukoplakia (white plaque)
- Leukoerythroplakia (speckled plaque)
- Oral lichen planus
- Oral submucous fibrosis
- Actinic or solar cheilitis
- Oral discoid lupus erythematosus
- Chronic oral graft-versus-host disease (GVHD)
- Risk for malignant transformation:
- ↑ With age
- ↑ With the age of the lesion
- ↑ With alcohol consumption
- Depends on the anatomical site of the premalignant lesion
- Over 90% of head and neck cancer is SCC.
- The remainder is adenocarcinoma of the salivary gland with tumors mainly arising from the mucosal epithelium.
- SCC development:
- Mutations and epigenetic changes accumulate, which affect the expression of oncogenes and tumor suppressor genes.
- Major pathways:
- Tobacco and alcohol: overexpressed p53 gene
- HPV: inactivated Rb gene, leading to overexpressed p16 gene
- Progression of squamous epithelium in response to toxin/HPV exposure → hyperkeratosis → dysplasia → carcinoma in situ → cancer
- Anatomical sites frequently involved:
- Lateral and ventrolateral tongue
- The floor of the mouth
- Buccal mucosa
- Retromolar trigone: attached mucosa overlying the ascending ramus of the mandible (posterior to the last molar tooth) and extending superiorly to the maxillary tuberosity
- Oral features:
- Red or red-white lesion(s)
- Persistent oral swelling
- Mouth ulceration
- Sore tongue
- Unexplained tooth mobility
- Unusual bleeding in the mouth
- Other related signs and symptoms:
- Difficulty swallowing
- Jaw or facial swelling
- Painless neck lump (lymphadenopathy)
Biopsy is recommended for suspicious oral lesions lasting 3 or more weeks:
- Especially indurated (firm on palpation) lesion(s) or a combination of lesions
- Established by lesion biopsy
- Panendoscopy (to determine tumor extent)
- Imaging (to locate metastasis):
- Chest X-ray
- CT and MRI
- PET-CT scans
- TNM staging for oropharyngeal cancers:
- Primary tumor (T):
- TX: Primary tumor cannot be assessed.
- T0: no evidence of primary tumor
- Tis: carcinoma in situ
- T1: tumor ≤ 2 cm in greatest dimension
- T2: tumor > 2 cm but ≤ 4 cm
- T3: tumor > 4 cm
- T4: Tumor invades adjacent structures (e.g., mandible, skin, muscle).
- Regional lymph nodes (N):
- NX: Regional lymph nodes cannot be assessed.
- N0: no regional lymph node metastasis
- N1: metastasis in a single, ipsilateral lymph node ≤ 3 cm
- N2a: metastasis in a single, ipsilateral lymph node > 3 cm but < than 6 cm
- N2b: metastasis in multiple, ipsilateral lymph nodes all < 6 cm in greatest dimension
- N2c: metastasis in bilateral or contralateral lymph nodes all < 6 cm in greatest dimension
- N3: metastasis in any lymph node > 6 cm
- Distant metastasis (M):
- M0: no evidence of distant metastasis
- M1: distant metastasis
- Primary tumor (T):
- Spreading of the tumor to a contralateral lymph node is prognostically worse than spreading into multiple, ipsilateral lymph nodes.
|0||TisN0M0 (in situ or cancer limited to epithelium)|
|I||T1N0M0 (lesion ≤ 2 cm and without node involvement or distant spread)|
|II||T2N0M0 (lesion > 2 cm but < 4 cm without node involvement or distant metastasis)|
|IV||Invasion of adjacent structures or distant metastasis|
Management and Prognosis
- Early cancer (stages I and II):
- Surgical resection: > 3 mm tumor invasion for stage I lesions; neck dissection for stage II lesions
- Radiotherapy if surgery is not feasible
- Locoregionally advanced cancer (stage III and IV): aggressive lesions, with a high rate of recurrence even with surgery or radiotherapy:
- Surgery + neck dissection:
- Maxillectomy/mandibulectomy: bone involvement
- Glossectomy: tongue involvement
- Laryngectomy: larynx involvement
- Followed by radiotherapy with or without chemotherapy
- Surgery + neck dissection:
- Inoperable tumors: radiotherapy or radiotherapy + chemotherapy
- Additional management:
- Cancer surveillance
- Functional rehabilitation
- Educate on tobacco cessation, alcohol cessation, and other high-risk factors.
- Five-year survival:
- Early oral cancer: 82.5%
- Locally advanced oral cancer: 54.7%
- Recurrence and 2nd primary malignancy risk:
- > 80% of stage III and IV cancers recur within 4-years posttreatment.
- Frequent surveillance needed:
- In the 1st 4 years
- For patients with continued high-risk behavior (i.e. smoking, alcohol consumption)
- Most important factor in prognosis: involvement of lymph node(s)
- Aphthous stomatitis: round-to-oval, painful ulcers with a crater-like appearance on a yellow-gray base with erythematous margins. Mucosal ulcers are on nonkeratinized mucosal surfaces only. Recurrence of ulcers is common and does not involve systemic symptoms. Aphthous stomatitis commonly occurs after minimal trauma (e.g., tongue biting). Management is supportive.
- Oral candidiasis: presents as white plaques on the oral mucosa, which can be scraped off with a tongue depressor. 90% of cases are due to Candida. Predisposing conditions include ill-fitting dentures, immunosuppression, and corticosteroid inhaler use. Oral candidiasis is common in pediatrics, particularly in small children. Management is with antifungal mouthwash.
- Herpetic gingivostomatitis: presents as painful, perioral vesicular lesions in clusters. The condition is contagious and caused by herpes simplex virus type 1. Herpetic gingivostomatitis is more common in children and at 1st exposure to the herpes virus, which is also responsible for cold sores and fever blisters. Management is supportive, but antivirals can be used.
- Herpangina: a common childhood illness often caused by group A coxsackieviruses. The presentation includes oral lesions (usually with a white base and a red border) and a prodrome of fever, anorexia, irritability, malaise, sleeplessness, and headache. The lesions typically involve the posterior pharynx and may be very painful. Management is supportive.
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