Introduction
Nasopharyngeal carcinoma (NPC) is a squamous cell carcinoma of an undifferentiated type. This cancer is endemic among Chinese, having the highest incidence of 10 to 20 per 100,000 for men and 5 to 10 per 100,000 for women. It is sometimes called the “Cantonese Cancer” because of its prevalence as one of the most common cancers of the head and neck among Chinese. The most common site of origin of NPC is from the epithelial lining of the area posteromedial to the medial crura of the Eustachian tube opening in the nasopharynx, which is also called the fossa of Rosenmüller.
Several serologic markers have become useful as a means of screening, diagnosing, and monitoring NPC after establishing that it is closely related to the Epstein-Barr virus (EBV), a double-stranded DNA virus. NPC has since become a model for EBV viral carcinogenesis after studies showed that most NPC cancer cells express EBV proteins and carry the clonal EBV genomes. Screening in the general population can now be done using serologic markers, such as EBV VCA immunoglobulin A (IgA) and DNase, whereas reverse transcription polymerase chain reaction (RT-PCR) methods measure EBV DNA copy numbers in plasma to monitor treatment response and early detection of local recurrence.
To summarize:
- 1.
For general population screening, serologic diagnosis can be made using EBV VCA IgA.
- 2.
For early detection of local recurrence, a nasopharyngeal swab should be taken for LMP-1 gene detection.
- 3.
For monitoring treatment response and to detect possible recurrence, RT-PCR–based plasma cell–free EBV DNA detection should be used.
- 4.
Currently available therapeutic modalities for NPC are radiation therapy (RT), chemotherapy, or a combination of both. Effective local control is more than 80% using the current RT techniques because of the high radiosensitivity of NPC. A high cure rate is seen among patients with early-stage cancer who undergo RT. Cisplatin-based chemoradiotherapy with or without neoadjuvant chemotherapy has demonstrated significant survival improvement and is currently the standard treatment strategy for patients with advanced locoregional disease.
Despite being a radioresponsive tumor, 10% to 30% of NPC patients develop local failure in the nasopharynx after the initial RT treatment. Whether it is persistence or recurrence after the initial radiation therapy (RT)/concurrent chemoradiation therapy (CCRT), salvage nasopharyngectomy is the treatment of choice. Proceeding with a second course of RT will only expose the patient to the risk of developing osteoradionecrosis (ORN) of the skull base, a potentially fatal complication of high-dose RT, without any assurance that the previously treated NPC cells will respond. Salvage nasopharyngectomy results in better outcomes than most of the published literature on re-radiation.
However, nasopharyngectomy requires skill and training and has posed a real challenge for head and neck surgeons. With the advances in skull base surgery, it is now possible to effectively control NPC recurrence or persistence using salvage nasopharyngectomy with acceptable mortality and morbidity.
Key Operative Learning Points
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Try to preserve or reestablish the blood supply to the bone when performing a facial bone disassembly.
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Perform a medial maxillectomy and posterior septectomy to improve exposure and increase the area of working space.
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During resection, the deep margin is marked by the pharyngobasilar fascia while making sure to remove as lateral as possible including the Eustachian tube cartilage.
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Depending on the extent of the cancer, several different approaches may be used.
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The use of rigid three-point bone segment fixation may prevent nonunion or ORN.
Preoperative Period
Local failure (persistence and recurrence in the nasopharynx) occurs in 16% to 48% of patients with NPC after initial RT. Salvage nasopharyngectomy has become the mainstay of treatment after RT failure, and the key to a successful surgery is proper patient selection. Preoperative period is essential to ensure that the patient is eligible for salvage nasopharyngectomy.
Before proceeding with nasopharyngectomy, all patients require thorough medical history including medical status, physical examination, as well as endoscopic examination. Firstly, it must be established that (1) these patients do have local recurrence or persistent NPC by performing biopsy(s) of the primary site, (2) ultrasound and possible guided fine-needle aspiration biopsy for any suspicious regional recurrence should be used, and (3) there is no distant metastasis. It is advisable to use Positron emission tomography–computed tomography (PET-CT) to exclude the possibility of distant metastasis. MRI with its excellent soft tissue resolution may also be used to evaluate the extent of the cancer and help to plan the surgical approach accordingly.
Other important preoperative preparation includes blood group and matched packed cells and preoperative antibiotic. Patients with pre-existing significant comorbidities should receive special attention. Anticoagulants or antiplatelet medications should be withheld (if possible) before salvage nasopharyngectomy.
History
- 1.
History of present illness
- a.
Nasal symptoms: blood-stained nasal discharge, nasal blockage
- b.
Aural symptoms: ear blockage, hearing loss, and otorrhea
- c.
Mass in the neck
- d.
Skull base and cranial nerve involvement
- 1)
Intractable headache
- 2)
Sixth cranial nerve involvement, which will result in abducens palsy
- 3)
Unilateral facial numbness from involvement of the fifth cranial nerve
- 1)
- e.
Symptoms suggesting distant metastasis
- f.
Weight loss, nutritional status
- g.
Smoking
- a.
- 2.
Past medical history
- a.
Previous radiotherapy with or without chemotherapy
- b.
Previous surgery for NPC
- c.
Pulmonary disease, hypertension, diabetes, or ischemic heart disease
- d.
Immunosuppression (e.g., acquired immunodeficiency syndrome [AIDS])
- a.
- 3.
Medications
- a.
Anticoagulants
- b.
Allergies to antibiotics or analgesia
- a.
Physical Examination
- 1.
Nasal cavity and nasopharynx
- a.
Endoscopic examination of the nasopharynx may reveal a mass in the fossa of Rosenmüller and sometimes a small submucosal swelling.
- b.
Determine extent of the cancer.
- 1)
Lateral extension
- a)
Eustachian tube
- b)
Torus tubarius
- a)
- 2)
Roof of nasopharynx and posterior choanae
- 3)
Inferior extension to oropharynx
- 1)
- a.
- 2.
Examination of the neck
- a.
Palpate both sides of the neck for the presence of cervical metastases.
- a.
- 3.
Examination of the skull base and cranial nerves
- 4.
Trismus
- a.
Anticipate difficult intubation. May require a tracheostomy
- a.
- 5.
Examination of the ears
- a.
Middle ear effusion
- a.
- 6.
Examine oral cavity, pharynx, and larynx for synchronous primaries.
- 7.
General health
- a.
Nutrition
- b.
Cardiovascular
- c.
Respiratory
- d.
Abdominal
- a.
Imaging
- 1.
Magnetic resonance imaging (MRI)
- a.
Superior soft tissue resolution and tumor delineation
- 1)
Parapharyngeal space or infratemporal fossa
- 2)
Intracranial extension
- 3)
Perineural invasion
- 4)
Deep invasion to the vertebral body
- 5)
Vascular involvement (carotid artery, cavernous sinus)
- 1)
- b.
Presence of cervical metastasis
- a.
- 2.
PET-CT scans
- a.
Restaging
- b.
Exclude cervical metastasis.
- c.
Exclude distant metastasis (bone, lung, liver).
- a.
- 3.
CT scan
- a.
Not required in all cases
- b.
MRI is preferred, if available
- a.
- 4.
Chest radiograph
- a.
Lung metastases
- b.
Pulmonary and cardiac status
- a.
- 5.
Ultrasound of the liver
Indications
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Recurrent cancer confined to the nasopharynx
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Modified/classical facial translocation for cancer with lateral extension medial to the foramen ovale
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Combined preauricular infratemporal subtemporal approach together with a transfacial/facial translocation approach for rNPC extend lateral to the foramen ovale and into the parapharyngeal space. (It is usually difficult to achieve a sound oncologic resection [no safety margin], and thus a second course of combined chemoradiation therapy might be a better option.)
Contraindications
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Patients with proven distant metastasis
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Cancer involving the dura.
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Encasement of the petrous part of the internal carotid artery
Preoperative Preparation
- 1.
Multidisciplinary team evaluation
- a.
Otolaryngologist—head and neck surgeon
- b.
Oncologist
- c.
Anesthesiologist
- d.
Nutritionist (if necessary)
- a.
- 2.
Physician
- a.
If required optimizing medical illness (cardiopulmonary disease)
- a.
- 3.
Confirm the histopathologic report before definitive surgery.
- 4.
Review the radiologic imaging (PET-CT and MRI) for planning of resection of the cancer and surgical approach.
- 5.
Treat sinusitis if present.
- a.
A bacterial culture of nasal secretion is obtained and culture-directed antibiotics prescribed for at least 7 days.
- b.
Perform frequent nasal douching with saline before surgery.
- a.
- 6.
Postoperative high dependency care (depending on the center)
- 7.
Discontinue antiplatelet drugs if possible.
Operative Period
Anesthesia
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All salvage nasopharyngectomy operations are performed under general anesthesia.
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Endotracheal intubation through the oral cavity
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Fiberoptic-guided intubation may be needed for patients presenting with trismus.
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In rare circumstances, tracheostomy should be considered in patients with severe trismus.
Positioning
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The patient is placed in the supine position.
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The head is turned to the contralateral side and slightly extended.
Perioperative Antibiotic Prophylaxis
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Clean-contaminated surgery
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Prophylaxis intravenous antibiotics should be administered 2 hours before surgery based on the bacterial culture result (if available).
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Choice of intravenous antibiotic may differ among surgeons, but a broad-spectrum antibiotic with good cerebral spinal fluid (CSF) penetration is recommended.
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Succeeding doses of intravenous antibiotics can be given every 6 hours if the surgery lasts longer.
Monitoring
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Routine anesthesia monitoring
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Hypotensive anesthesia (to reduce intraoperative bleeding that will obscure operative field)
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Prevent hypothermia by using intraoperative warm-air blanket.
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Maintain fluid balance and hemoglobin level.
Instruments and Equipment to Have Available
The different open approaches to the nasopharynx require dissection through soft tissue and facial bones. The instruments and equipment required to carry out a successful surgery are:
- 1.
Excision set
- 2.
Sinuscope set (0- and 30-degree Hopkins telescopes)
- 3.
Osseous set with oscillating saw, burr, and reconstructive plate and screws
- 4.
Skull base set including Kerrison rongeurs, forceps, curettes, tru-cutting instruments, and dissectors
- 5.
Cutting and diamond burrs
- 6.
Contact LASER set with curved applicator
- 7.
Bipolar cauterization set
Surgical Anatomy
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The nasopharynx, a hollow cubic space above the soft palate and posterior to the nasal cavity
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The most cephalad portion of the upper aerodigestive tract
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Lined by pseudostratified ciliated columnar epithelium
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Boundaries:
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Superior: sphenoid sinus and upper clivus
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Posterior: lower clivus and the body of the first cervical vertebra
- •
Lateral: medial pterygoid plate (formed by an incomplete cartilaginous ring with a natural defect inferolaterally called the sinus of Morgagni).
- •
Anterior: communicates with the posterior nasal choanae
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Inferior: communicates with the oropharynx
- •
- •
The posterior and lateral wall of the nasopharynx are demarcated by the pharyngobasilar fascia, a dense and tough fascia that originates from the pharyngeal tubercle of the occipital bone posteriorly and inserts anteriorly into the posterior sharp end of the medial pterygoid plate (serves as a good barrier to the spread of NPC).
- •
It continues inferiorly as the buccopharyngeal fascia.
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The spread of NPC
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Superiorly: floor of the sphenoid sinus and invades the sphenoid sinus and skull base
- •
Laterally: through the sinus of Morgagni, extending along the Eustachian tube toward the base of the pterygoid plate and into the parapharyngeal space, eventually gaining access into the area of the foramen ovale
- •
- •
NPC that spreads laterally to the foramen lacerum may involve or encase the petrous internal carotid artery, which would then prevent complete resection of the recurrent cancer.
Prerequisite Skills
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Surgeons should be familiar with development and elevating a skin flap, as well as osteotomies.
- •
Basic skills to manage intraoperative bleeding in a relative narrow and deep space are mandatory.
Operative Risks
Because the nasopharynx is closely related to the cavernous sinus, internal carotid artery, and dura, iatrogenic injury to these vital structures can be life threatening and render the nasopharyngectomy some operative risks with potentially devastating consequences.
Surgical Technique
Salvage nasopharyngectomy has been the mainstay of treatment after radiation failure. Various surgical approaches to the nasopharynx have been developed, such as transpalatal, midface degloving/Le Fort I osteotomy, transfacial/facial translocation/transmaxillary, mandibulotomy, transpterygoid, and infratemporal fossa approaches.
Intraoperative Evaluation and Preparation After Patient Has Been Intubated
- •
Ensure that the nasal cavities are properly decongested and anesthetized using cotton pledgets soaked in epinephrine with a 1:100,000 dilution for 15 minutes.
- •
Inspect the nasopharynx carefully using a rigid endoscope to examine the entire cancer and make a good surgical plan.
- •
Infiltrate the planned facial incisions, mucoperichondrium of the nasal septum, middle and inferior turbinates, and the area around the cancer using a combined solution of 1% lidocaine and 1:80,000 epinephrine.
Le Fort I Osteotomy via Midfacial Degloving Operative Technique
The steps for this technique are as follows:
- 1.
Standard transfixion incision from the tip of the nose inferiorly to the nasal floor
- 2.
An intercartilaginous incision is placed and extends laterally beyond the margin of the upper lateral cartilages and connects medially with the transfixion incision. Circumvestibular release is completed with a full-thickness incision at the pyriform aperture and nasal floor up to the periosteum.
- 3.
Separate the dorsum of the nose and upper lateral cartilages by dissecting through the intercartilaginous incisions using a Freer elevator.
- 4.
Make a horizontal incision above the gingivobuccal sulcus from one maxillary tuberosity to the other then elevate the periosteum, exposing the anterior and lateral maxillary walls.
- 5.
Extend the dissection to the edge of the piriform aperture and to the incisions placed intranasally to allow elevation of the upper lip together with the tip of the nose. Maintain a cuff of mucosa to allow easy closure of the gingiva.
- 6.
Dissect the soft tissues up to the infraorbital rim, exposing and identifying the infraorbital nerve, lateral maxillary wall, piriform aperture, and the zygomatic pillar of the maxilla. The infraorbital nerve is preserved unless it is involved by the cancer. Mobilization of the soft tissues can be extended superiorly up to the nasofrontal angle and glabellar area.
- 7.
Place titanium miniplates over the bony maxilla, prefolded; then screw holes are made.
- 8.
Perform a horizontal maxillary osteotomy starting anteriorly from the piriform aperture toward the lateral wall of the maxilla and the zygomatic pillar.
- 9.
Separate the nasal septum from the anterior nasal spine and maxillary septal crest using a sharp osteotome while avoiding laceration of the nasal mucosa.
- 10.
An osteotomy is then performed to separate the maxilla using a sharp chisel from the piriform aperture posteriorly to the pterygoid plates and palatine canal vessels passing through the inferior meatus.
- 11.
Finally, downfracture the maxilla.
- 12.
Dissection is limited laterally by the pterygoid and temporal muscles; posteriorly by the clivus, posterior wall of the sphenoidal sinus, and the greater wing of the sphenoid bone; and superiorly by the anterior cranial fossa.
- 13.
After excision of the tumor, the bony buttresses are approximated using wiring or titanium plates and 4 weeks of intermaxillary fixation.
Facial Translocation Approach
The technique of developing a lateral nasal wall mucoperiosteal flap in the modified facial translocation approach:
- 1.
Infiltrate the nasolabial groove using a solution of 1% lidocaine mixed with 1:100,000 epinephrine and proceed with a lateral rhinotomy incision.
- 2.
The incision is placed along the nasal ala without involvement of the nostril and is carried down in a stepwise fashion.
- 3.
As the incision is developed, stop first at the medial edge of the maxillary bone, making sure to preserve the mucoperiosteum of the lateral nasal wall. Do not transect the full thickness of the lateral nasal wall while gaining access into the nasal chamber and dividing the feeding vessels.
- 4.
Using a Cottle elevator, gently elevate the mucoperiosteum of the lateral nasal wall from the lateral bony wall of the maxilla. Continue elevating the mucoperiosteum posteriorly toward the posterior end of the inferior turbinate, superiorly toward the middle turbinate until the natural orifice of the maxillary sinus is reached, and inferiorly to the nasal floor ( Figs. 43.1, 43.2 ).
