Oropharyngeal Cancer

Oropharyngeal cancer is a malignant tumor arising from the oropharynx, which is the middle portion of the pharynx located between the soft palate superiorly and the hyoid bone inferiorly.

The oropharynx consists of four major anatomical regions:

• Soft palate.

• Tonsillar region.

• Base of the tongue.

• Pharyngeal wall.

Oropharyngeal cancers are commonly associated with tobacco use, alcohol consumption, and human papillomavirus (HPV) infection. Tumors arising from the tonsillar region and base of tongue frequently present initially with cervical lymph node metastases rather than symptoms from the primary tumor.

Epidemiology

Oropharyngeal cancer is an important malignancy of the head and neck region. The incidence is influenced by exposure to traditional risk factors such as tobacco and alcohol, as well as HPV infection.

HPV-associated tumors represent an important subgroup and may have different biological behavior compared with tobacco-related cancers.

Risk factors

Risk factors associated with oropharyngeal cancer include:

• Tobacco smoking.

• Excessive alcohol consumption.

• Human papillomavirus (HPV) infection.

• Increasing age.

• Male sex.

• Poor oral hygiene.

• Chronic exposure to carcinogens.

Pathophysiology

Oropharyngeal cancer develops through malignant transformation of epithelial cells lining the oropharynx.

Carcinogenesis may occur through:

• Tobacco and alcohol-related cellular damage.

• HPV-related oncogenic transformation.

• Genetic mutations causing uncontrolled cell growth.

Progression may lead to:

• Local invasion of surrounding tissues.

• Impairment of swallowing and speech functions.

• Cervical lymph node metastasis.

• Distant metastasis in advanced disease.

The tonsillar region and base of tongue have rich lymphatic drainage, contributing to early nodal involvement.

Clinical presentation

Clinical presentation depends on:

• Primary tumor site.

• Tumor size.

• Presence of cervical lymph node metastasis.

• Local invasion into adjacent structures.

Some patients initially present because of enlarged neck lymph nodes.

Symptoms

Common symptoms include:

• Sore throat.

• Non-healing oropharyngeal ulcer.

• Dysphagia.

• Referred ear pain (otalgia).

• Hoarseness of voice due to laryngeal invasion.

• Odynophagia.

• "Hot potato" voice.

• Impaired tongue movement, including difficulty protruding the tongue.

• Neck swelling due to lymph node involvement.

Clinical signs

Clinical findings may include:

• Oropharyngeal ulcer or mass.

• Tonsillar enlargement or asymmetry.

• Base of tongue lesion.

• Cervical lymphadenopathy.

• Reduced tongue mobility.

• Voice changes.

• Signs of local extension.

Differential diagnosis

Conditions that may mimic oropharyngeal cancer include:

• Chronic tonsillitis.

• Peritonsillar abscess.

• Benign tonsillar lesions.

• Oral cavity cancer.

• Laryngeal cancer.

• Hypopharyngeal cancer.

• Lymphoma.

• Tuberculosis of cervical lymph nodes.

Diagnostic criteria

Oropharyngeal cancer should be suspected in patients presenting with:

• Persistent sore throat.

• Non-healing oropharyngeal ulcers.

• Progressive dysphagia.

• Persistent odynophagia.

• Neck mass.

• Unexplained referred ear pain.

• Voice changes.

Definitive diagnosis requires histopathological confirmation by biopsy.

Investigations

Laboratory investigations

• Full blood count (FBC).

• Liver function tests (LFT).

• Renal function tests (RFT).

• HIV test.

Imaging investigations

• Chest X-ray (CXR).

• Computed tomography (CT) scan of the head and neck.

• Magnetic resonance imaging (MRI) of the head and neck.

Imaging assesses:

• Primary tumor extent.

• Local invasion.

• Cervical lymph node involvement.

• Distant disease.

Endoscopic examination

• Mirror examination.

• Fibre-optic endoscopic examination.

Histopathological investigation

• Biopsy of the lesion for histologic confirmation.

Diagnostic staging

Oropharyngeal cancer is staged using:

• TNM staging system.

Management

Management depends on:

• Disease stage.

• Tumor site.

• HPV status where applicable.

• Resectability.

• Patient general condition.

Treatment options include:

• Radiotherapy.

• Chemotherapy.

• Surgery in selected cases.

Most patients require multidisciplinary management involving head and neck surgeons, radiation oncologists, medical oncologists, radiologists, and pathologists.

Non-pharmacological treatment

Radiotherapy

Radiotherapy is a major treatment modality for oropharyngeal cancer, particularly when combined with chemotherapy.

Curative radiotherapy

For head and neck cancers:

• Total dose: 66–70 Gy.

• Conventional fractionation: 1.8–2 Gy per fraction.

Radiotherapy may be used:

• As definitive treatment.

• Combined with chemotherapy for locally advanced disease.

• As adjuvant treatment after surgery when indicated.

Surgery

Surgery may be considered in selected cases depending on:

• Tumor location.

• Disease extent.

• Resectability.

• Functional outcomes.

Pharmacological treatment

Concurrent chemotherapy with radiotherapy

Used for locally advanced disease.

Regimen 1

Cisplatin

• IV 40 mg/m².

• 1-hour infusion.

• Weekly during radiotherapy.

OR

Regimen 2

Cisplatin

• IV 75 mg/m².

• 1-hour infusion on Day 1.

• Repeat every 21 days during radiotherapy.

Induction chemotherapy

For patients with advanced head and neck cancers.

Induction chemotherapy may include:

• PF regimen.

• TPF regimen (taxane, platinum, and 5-fluorouracil).

Carboplatin + 5-fluorouracil + paclitaxel regimen

Carboplatin

• IV AUC 5.

• 1-hour infusion on Day 1.

AND

5-fluorouracil

• IV 400 mg/m² bolus on Day 1.

AND

Paclitaxel

• IV 175 mg/m².

• 3-hour infusion on Day 1.

Repeat every 21 days for 3–6 cycles.

Adjuvant chemotherapy

For curative intent treatment:

• Concurrent chemoradiotherapy is indicated with cisplatin/5-fluorouracil.

If induction chemotherapy was not given, adjuvant chemotherapy may be considered.

Carboplatin + 5-fluorouracil + cetuximab regimen

Carboplatin

• IV AUC 5.

• 1-hour infusion on Day 1.

AND

5-fluorouracil

• IV 400 mg/m² bolus on Day 1.

AND

Cetuximab

• IV 400 mg/m².

• 2-hour infusion on Day 1.

• Administered 1 hour before cisplatin/5-fluorouracil.

Repeat every 21 days for 3–6 cycles.

Treatment of recurrent or metastatic disease

Combination therapy options

Regimens may include:

• Cisplatin or carboplatin with docetaxel or paclitaxel.

• Paclitaxel/cisplatin/5-fluorouracil.

• Cisplatin/gemcitabine.

• Gemcitabine/vinorelbine.

• Carboplatin/cetuximab.

Single-agent therapy options

May include:

• Cisplatin.

• Carboplatin.

• Paclitaxel.

• Docetaxel.

• 5-fluorouracil.

• Methotrexate.

• Gemcitabine.

• Capecitabine.

Management according to disease stage

Early-stage disease

Management options:

• Radiotherapy as definitive treatment.

OR

• Surgery in selected cases.

Locally advanced disease

Management:

• Concurrent chemoradiotherapy.

Induction chemotherapy may be considered in selected advanced cases.

Recurrent or metastatic disease

Management:

• Systemic therapy.

• Palliative radiotherapy when indicated.

• Supportive care.

Referral

All patients with suspected or confirmed oropharyngeal cancer should be referred to specialized cancer centers for:

• Histological confirmation.

• TNM staging.

• Treatment planning.

• Definitive management.

Urgent referral is required for:

• Persistent throat symptoms.

• Neck mass.

• Progressive swallowing difficulty.

• Non-healing oral or oropharyngeal lesions.

Complications

Complications may include:

• Cervical lymph node metastasis.

• Airway obstruction.

• Severe swallowing difficulty.

• Malnutrition.

• Speech impairment.

• Local recurrence.

• Distant metastasis.

• Treatment-related complications.

Prognosis

Prognosis depends on:

• Disease stage.

• HPV status.

• Tumor site.

• Cervical lymph node involvement.

• Response to treatment.

• General health status.

HPV-associated tumors may have different outcomes compared with tobacco-related disease.

Prevention

Preventive strategies include:

• Avoidance of tobacco use.

• Reduction of alcohol consumption.

• HPV prevention measures.

• Maintaining good oral hygiene.

• Early assessment of persistent throat symptoms.

Follow-up

Follow-up is required to monitor:

• Treatment response.

• Local recurrence.

• Regional lymph node recurrence.

• Distant metastasis.

• Treatment complications.

Recommended follow-up schedule:

• First visit: 4–6 weeks after completion of treatment.

• Every 3–4 months during the first year.

• Every 6 months during the second year.

• Annually thereafter.