Transoral and Robotic Tonsil Surgery for Cancers of the Base of the Tongue and Pharynx

Introduction

Almost 50,000 people develop oral and oropharyngeal cancers each year with almost 9000 deaths annually. When diagnosed and treated in its early stages, 5-year survival rates can exceed 83%.

Oropharyngeal cancer is on the rise, and in particular, human papilloma virus (HPV)–related cancers have increased in the United States by 225% since 1998. Historically, open surgery of the oropharynx was fairly morbid and invasive and was noted to have comparable outcomes to primary chemoradiotherapy. In the mid 2000s, with the advent of the surgical robot and its use by Drs. Weinstein and O’Malley, oropharyngeal surgery was revolutionized, making it less morbid and allowing for the potential of de-escalation therapy.

Having a standardized set of techniques (similar to laryngectomy) allows for consistent margin control in a safe and effective manner and follows Halstedian principles of en bloc resection.

Patient selection is of the utmost importance because margin-negative resection is highly predictive of overall survival in head and neck cancers.

Key Operative Learning Points

1.
Knowledge of inside-out anatomy is key to a safe and effective operation, particularly when approaching the oropharynx transorally.
2.
Halstedian principles of oncologic surgery must be maintained when removing tumors, allowing for adequate margins and decreased tumor spillage.
3.
Ligating feeding vessels to the oropharynx during the neck dissection can aid in prevention of postoperative hemorrhage.
4.
In cases of the unknown primary with HPV+ squamous cell carcinoma, the most commonly affected site is the oropharynx and can be easily sampled en bloc for pathologic analysis.
5.
Reconstruction is important when addressing this area because it is vital in the functions of speech, breathing, and deglutition.

Preoperative Period

History

1.
History of present illness
- a.
  Many patients will present initially with a mass in the neck; in these cases, questions regarding onset, location, duration, exacerbation, and any treatments may give insight into the underlying etiology of the mass (vascular, infectious, autoimmune, neoplastic).
- b.
  The patient should be questioned regarding dysphagia, odynophagia, otalgia, weight loss, hemoptysis, hoarseness, dysgeusia, and dyspnea, because these are most likely to be seen in patients with underlying malignancy.
- c.
  Current treatment with antibiotics or other medications.
2.
Past medical history
- a.
  Prior treatment: Any antibiotics or recent viral illnesses
- b.
  Medical illness: History of other head and neck cancers (which can be seen in more than 36% of patients who smoke), history of lung cancer, history of cervical cancer, previous surgery in the oropharynx
  - 1)
    Any illnesses that would be contraindications for surgical intervention including significant cardiovascular, pulmonary, or other end-stage cancers
  - 2)
    Hypercoagulable disorders requiring chronic anticoagulation
  - 3)
    Coagulopathy including von Willebrand disease or other
  - 4)
    Stents requiring antiplatelet therapy
  - 5)
    Significant sleep apnea (to understand postoperative risk of flash pulmonary edema and/or need for tracheostomy)
  - 6)
    History of aspiration events
  - 7)
    History of autoimmune disorders or transplantation requiring long-term antirejection therapy
- c.
  History of radiation to the head or neck area (including for Hodgkin, treatment of acne)
- d.
  Surgery
  - 1)
    Previous tonsillectomy or sleep apnea surgery
  - 2)
    Any neck surgery
  - 3)
    Arm and leg surgery (in case the patient may require free flap reconstruction)
- e.
  Family history
  - 1)
    History of head and neck cancers
  - 2)
    Autoimmune disorders
  - 3)
    Cervical cancer in significant other (Data from the Swedish Cancer Registry (1958–1996) showed that spouses of patients with cervical cancer had a significantly elevated risk of development of tongue or tonsil cancer.)
- f.
  Medications
  - 1)
    Antiplatelet drugs or anticoagulant medications
  - 2)
    Immunosuppressive medications
  - 3)
    Herbal products (fish oil, valerian root)
- g.
  Social History
  - 1)
    Alcohol
  - 2)
    Smoking tobacco
  - 3)
    Illicit or recreational drugs
  - 4)
    Support system at home
  - 5)
    Current occupation

Physical Examination

1.
Overall appearance and breathing
- a.
  Note quality of breathing—mouth breathing or stridor; signs of obstruction, drooling or dry mouth
- b.
  Examine for cachexia, temporal wasting
- c.
  Some patients will have a characteristic foul odor of the breath, particularly those with larger cancers.
2.
Examination of the cranial nerves
- a.
  In particular, lower cranial nerves (IX, X, XI, XII), because involvement indicates a significant disease process
3.
Oral cavity/oropharynx
- a.
  Examine lips, gums, teeth, floor of mouth, tongue, and visible oropharynx with two tongue blades.
- b.
  Bimanual palpation of lips, floor of mouth, tongue, base of the tongue, cheeks, and hard palate
- c.
  Mirror examination if patient tolerates; flexible endoscopy if not
4.
Nasal cavity
- a.
  Anterior rhinoscopy can be performed to evaluate for intranasal growths. Topical anesthetic and decongestant can also be applied at this time in preparation for nasal endoscopy.
5.
Neck
- a.
  Palpation of the lymph node basins of the neck from level Ia to level V
  - 1)
    Any lymph nodes need to be assessed for fixation, mobility in certain directions
- b.
  Palpation of the thyroid gland

Imaging

Computed tomography (CT): CT with contrast should be done to better characterize the remaining neck for occult disease that is not felt on physical examination. It can also provide information regarding involvement of vessels or local structures. Special attention should be paid to the location of the carotid artery to ensure that it does not have a retropharyngeal course as this is a contraindication for radical tonsillectomy.
Magnetic resonance imaging (MRI): MRI is particularly useful for lesions of the base of the tongue or unknown primaries, because it can detect subtle changes in soft tissue.
Staging scans: Positron emission tomography (PET) CT can evaluate from the brain to the upper thighs for metastatic cancer. At the least, a chest CT should be performed to evaluate for metastatic cancer to the lungs.

Indications

1.
Patients with primary T1, T2, T3, and select T4 lesions of the oropharynx with possible reconstruction
2.
Patients with recurrent cancer of the oropharynx; to be performed in conjunction with a reconstructive surgeon
3.
Metastatic cancer to the neck from an unknown primary as a part of the evaluation and treatment

Contraindications

1.
Medical comorbidities with increased risk for general anesthesia: End-stage cardiac disease (Preoperative risk assessment by a cardiologist is necessary.)
2.
End-stage cancer
3.
Involvement of the carotid artery
4.
Retropharyngeal carotid
5.
Relative contraindication: Prevertebral fascia involvement
6.
Relative contraindication: Pterygoid involvement (will require extensive reconstruction as part of planning)

Preoperative Preparation

Procedures

1.
Nasopharyngolaryngoscopy
- a.
  Allows examination of the mucosa from the nasal cavity to the larynx
  - 1)
    This is often helpful for assessing the extent of palate involvement and the status of the airway in anticipation of a visit to the operating room (OR).
  - 2)
    Predicting possibly problematic airways is very important. Often, pictures or video can be shared with the anesthesia team.
2.
Fine-needle aspiration (FNA) biopsy
- a.
  FNA can be performed on easily palpated cervical lymph nodes with or without ultrasound guidance as long as there is no evidence of involvement of the carotid artery.
- b.
  Some patients will tolerate biopsy of the oropharynx in the office.
- c.
  HPV typing should be done on the specimens.
- d.
  In patients for whom transoral robotic surgery (TORS) is to be considered, staging endoscopy is often necessary to determine the resectability of the tumor. Mobility of the tumor, involvement of adjacent structures, and exposure are all evaluated at the time of this endoscopy. If the tumor cannot be reached in the office setting, pan endoscopy with biopsy should be performed in the OR. This also gives the surgeon an idea of how well the cancer can be exposed, particularly if transoral resection is being planned or if the patient will require extensive reconstruction (in which case, a mandible split or a robotic approach may be necessary).
3.
Preoperative imaging
4.
Preoperative clearance
5.
Panendoscopy results with HPV testing
6.
Airway assessment
7.
Staged or concomitant neck dissection with ligation of vessels

Operative Period

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