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Oropharyngeal Squamous Cell Carcinoma
Oropharyngeal squamous cell carcinoma affects over 13,000 people in the US each year. Tobacco and alcohol are major risk factors, and the role of human papillomavirus (HPV) infection as a risk factor is increasing. Symptoms include sore throat and painful and/or difficult swallowing. Treatment is with radiation, chemotherapy, or both, but primary surgery has begun to be used more often. Survival rate is much higher in HPV-positive patients.
Oropharyngeal squamous cell carcinoma refers to cancer of the tonsil, base and posterior one third of the tongue, soft palate, and posterior and lateral pharyngeal walls. Squamous cell carcinoma comprises over 95% of oropharyngeal cancers.
In the US in 2015, there were an expected > 13,000 new cases of oropharyngeal cancer. Although the incidence of oropharyngeal cancer is increasing, its cure rates are also improving.
Like most head and neck cancers, oropharyngeal cancer is more common among older men with a mean age of 63. The male:female ratio is 2.7:1. However, recently, oropharyngeal cancer patients have become younger and more commonly female as HPV infection has emerged as an etiology. The risk of developing oropharyngeal cancer is 16 times higher in HPV-positive patients. In Europe and North America, HPV infection accounts for about 70 to 80% of oropharyngeal cancers. Nonetheless, tobacco and alcohol remain important risk factors for oropharyngeal cancer. Patients who smoke more than 1.5 packs/day have about a 3-fold increased risk of cancer, and patients who drink 4 or more drinks/day have about a 7-fold increased risk. People who both drink and smoke heavily have 30 times the risk of developing oropharyngeal cancer.
Oropharyngeal cancer symptoms vary slightly depending on the subsite but typically patients present with sore throat, dysphagia, odynophagia, dysarthria, and otalgia. A neck mass, often cystic, is a common presenting symptom of patients with oropharyngeal cancer. Because the symptoms of oropharyngeal cancer mimic those of common URIs, it often takes many months before patients are referred to a specialist.
All patients should undergo a direct laryngoscopy and biopsy before starting treatment to evaluate the primary lesion and to look for second primary lesions. Patients with confirmed carcinoma typically have neck CT with contrast, and most clinicians also do PET of the neck and chest.
Surgery is increasingly being used as primary treatment of oropharyngeal cancer. Transoral laser microsurgery (TLM) is increasingly being used to resect tumors of the tonsil and base of tongue endoscopically, avoiding the morbidity of open surgery. Transoral robotic surgery (TORS) is an increasingly popular means of treating select oropharyngeal lesions. In TORS, a surgical robot with multiple adaptable arms is controlled by a surgeon at a console. The articulating arms of the robot and an endoscopic camera are inserted through the patient's mouth (which is held open by a retractor). The robotic procedure provides better visualization of structures and causes less surgical morbidity compared to open surgery. However, the indications for using TORS are not yet well defined. When TORS is used on patients with more advanced tumors, postoperative radiation or chemoradiation is often done.
Radiation therapy, sometimes combined with chemotherapy (chemoradiation), can be used as primary therapy or postoperatively. Traditionally, radiation has been used for early-stage cancers and chemoradiation has been used for advanced cancers. Intensity-modulated radiation therapy (IMRT) has increasingly been used as a way to spare surrounding tissue and decrease long-term adverse effects.
Because the oropharynx is rich in lymphatics, cervical lymph node metastasis is common and must be considered in all patients with oropharyngeal cancer. If a cervical lymph node metastasis does not resolve after radiation or chemoradiation, post-treatment neck dissection is warranted.
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