Pharyngectomy - Clinical Tree

Introduction

A hollow viscus located immediately posterior to the larynx, the hypopharynx is related to the oral pharynx superiorly and the cervical esophagus inferiorly. It is divided into three anatomic sites: the pyriform sinuses (bilateral), the postcricoid mucosa, and the posterior pharyngeal wall. The postcricoid mucosa is the mucosa lying on the posterior aspect of the cricoid cartilage, which is also the anterior wall of the hypopharynx. The hypopharynx plays an important role in deglutition, as well as respiration. Coordinated activity in this laryngopharyngeal segment is essential for swallowing and protecting the airway from aspiration.

Squamous cell carcinoma of the hypopharynx accounts for only 3% to 5% of all head and neck squamous cell carcinomas. Development of carcinoma of the hypopharynx is closely associated with the use of both tobacco and alcohol products. Cancer of the hypopharynx has a dismal prognosis with the majority of patients initially diagnosed with stage IV cancer. Treatment is dependent on the stage at presentation and often involves a combination of surgery, radiation, and chemotherapy. Unfortunately, recurrence rates are high, approaching 50%, demonstrating the difficult task faced by head and neck surgeons in managing cancer of this unique subsite.

Key Operative Learning Points

1.
Squamous cell carcinoma of the hypopharynx has a propensity for regional metastases, and the majority of patients are diagnosed with stage IV cancer.
2.
The standard approach to treatment of cancer of the hypopharynx is either partial or total pharyngectomy, often combined with total laryngectomy, followed by adjuvant chemoradiation.
3.
Involvement of the prevertebral fascia and/or the common carotid artery is considered to be inoperable.

Preoperative Period

History

1.
History of present illness
- a.
  Common presenting signs and symptoms include dysphagia, odynophagia, referred otalgia, and a mass in the neck.
  - 1)
    The duration, severity, and quality of these symptoms should be elicited.
  - 2)
    Choking or coughing with meals may indicate aspiration.
- b.
  Hoarseness or stridor suggests laryngeal involvement.
2.
Past medical and surgical history
- a.
  A thorough past medical history should be obtained, including the patient’s pulmonary function and cardiac history.
- b.
  Has the patient been diagnosed with cancer of the head and neck in the past or previously been treated with radiation therapy?
- c.
  Is there a history of immunosuppression?
3.
Family history of cancer of the head and neck cancer or blood dyscrasias should be obtained.
4.
Medications
- a.
  A full list of medications should be obtained, including the use of anticoagulants, antiplatelets, or herbal products.
5.
Social history
- a.
  Determine the patient’s smoking and alcohol history, as these are the most common risk factors for hypopharyngeal cancer.
- b.
  Current alcohol use places the patient at risk for postoperative alcohol withdrawal.

Physical Examination

1.
Vital signs
- a.
  Basic vital signs, including oxygen saturation and body mass index (BMI)
2.
Examination of the head and neck
- a.
  Ears
  - 1)
    Referred otalgia is common with cancer of the hypopharynx.
- b.
  Oral cavity/oropharynx
  - 1)
    A thorough examination of the oral cavity and oropharynx is important to rule out synchronous primary cancers in these patients who typically have a history of heavy tobacco and alcohol consumption.
  - 2)
    Dental evaluation is important for pretreatment planning. Patients with poor dentition may need to have dental extractions prior to radiation therapy preferably at the time of surgery.
- c.
  Neck
  - 1)
    Lymphatic drainage of the hypopharynx is directed toward the superior deep cervical lymph nodes (zones II and III); however, some cancers of the hypopharynx may drain to the retropharyngeal lymph nodes, and bilateral drainage is also possible.
  - 2)
    Cancer involving the pyriform sinus has an approximately 20% risk of contralateral lymph node metastasis. The lateral wall of the pyriform is less likely than the medial wall to metastasize to the contralateral lymphatics.
3.
Flexible fiberoptic laryngoscopy
- a.
  A key portion of the examination is direct fiberoptic laryngoscopy to confirm the presence of a hypopharyngeal lesion, and to determine its extent.
- b.
  Does the cancer involve the endolarynx, post-cricoid region, or posterior pharyngeal wall?
- c.
  Does the cancer obstruct the airway? If the tumor causes significant obstruction of the larynx, an awake flexible fiberoptic intubation or an awake tracheostomy must be considered.
4.
Cardiac and pulmonary examination
- a.
  The status of these is a critical component of preoperative planning.
- b.
  Candidates for organ-preservation surgery require excellent pulmonary function status. Preoperative pulmonary function studies are usually adequate for this assessment.

Imaging

1.
Computed tomography (CT)
- a.
  CT of the neck with contrast is a quick, easy, and cost-effective method for evaluating the extent of cancer of the hypopharynx.
- b.
  Cervical lymph node metastases can be readily determined with CT. Metastatic cancer develops in 60% to 80% of patients with hypopharyngeal cancer. Occult lymph node metastases are present in at least 20% to 40% of patients. The risk is bilateral in patients with cancer involving the postcricoid mucosa, the medial wall of the pyriform sinus, or the posterior wall of the pharynx.
- c.
  CT of the chest is important to evaluate for pulmonary metastases in patients with advanced stage cancer.
2.
Magnetic resonance imaging (MRI)
- a.
  Compared to CT, MRI provides better visualization of soft tissue planes.
- b.
  MRI is useful in determining whether there is tumor involvement of the prevertebral fascia; a contraindication to surgery.
3.
Barium esophagram
- a.
  Fixation to the prevertebral fascia or bone can be ascertained preoperatively with video fluoroscopy when fixation of the pyriform sinus is recognized during swallowing.
4.
Positron emission tomography (PET)
- a.
  Because most patients present with advanced stage cancer, the risk of distant metastases at presentation is substantial. PET, often combined with CT, provides reliable pretreatment evaluation of distant metastatic spread.

Indications

1.
Partial laryngopharyngectomy
- a.
  This procedure is appropriate for patients with cancer limited to the aryepiglottic fold, the medial wall of the pyriform sinus, and the anterior wall of the pyriform sinus, as long as they have adequate pulmonary function. Extension to the apex or lateral wall of the pyriform sinus is a contraindication to this procedure.
2.
Total laryngectomy and partial pharyngectomy
- a.
  This procedure is most commonly performed in patients with carcinoma of the pyriform sinus that extends to involve the larynx medially, the apex of the pyriform sinus inferiorly, or the lateral wall of the hypopharynx laterally.
3.
Total laryngopharyngectomy
- a.
  Cancer involving the postcricoid mucosa, advanced cancer of the posterior hypopharyngeal wall, and cancer involving the pyriform sinus with extension across the midline posteriorly require total laryngopharyngectomy. More extensive cancers that extend into the cervical esophagus are resected via total laryngopharyngoesophagectomy.

Contraindications

1.
Extension of the cancer to the prevertebral fascia
- a.
  This can be evaluated with preoperative MRI and/or barium esophagram.
2.
Encasement of the common carotid artery
- a.
  While significant extension is visible on a preoperative CT scan, occasionally carotid artery involvement can only be determined intraoperatively. If carotid artery involvement is suspected but not confirmed preoperatively, we suggest starting with the neck dissection on the affected side in the event that the case must be aborted.
3.
Distant metastases
- a.
  It is imperative that these patients be discussed at a multidisciplinary conference for treatment options, including palliative care.

Preoperative Preparation

1.
Preoperative medical clearance, particularly with regard to cardiac and pulmonary status
2.
Laboratory tests should include a prealbumin and thyroid-stimulating hormone as these are correctable causes of delayed wound healing.
3.
Consider a gastrostomy tube if the patient is unable to swallow and is malnourished.
4.
Discontinue antiplatelet and anticoagulant medications if possible.
5.
Have any biopsy or imaging studies done at another hospital reviewed by in-house experts.

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