Nasopharyngectomy - An Overview

Introduction

The nasopharynx is situated at the base of the skull and above the roof of the mouth. Nostrils open into the nasopharynx. When an individual breathes, the air enters into the nose, then into the throat, the nasopharynx, and enters slowly into the lungs. Nasopharyngeal cancer is a disease in which the abnormal formation of cancer cells occurs in the tissues of the nasopharynx. It is one of the most common cancers in the nasopharynx. Endoscopic nasopharyngectomy is an effective treatment for nasopharyngeal cancer.

What Is Nasopharyngeal Cancer?

Nasopharyngeal cancer is a rare cancer of all head and neck cancers. It begins at the upper part of the throat, behind the nose. This is also known as nasopharyngeal carcinoma (NPC). Nasopharyngeal cancer can occur in the nasopharynx, the throat, the back of the nose, and at the base of the skull. Generally, it occurs in the head and neck region.

Early detection of NPC can be challenging as its symptoms are similar to other conditions and sometimes may mislead the diagnosis. Serological markers are used to screen, diagnose, and monitor NPC.

Radiation therapy (RT), chemotherapy, or a combination of both can be used for treatment. 80 percent of NPC can be controlled by RT because of the high radiosensitivity of NPC. Individuals in an advanced stage can be treated with Cisplatin-based chemotherapy. If local recurrence is suspected, a biopsy under nasopharyngoscopy should be done.

What Is Nasopharyngectomy?

Nasopharyngectomy is one of the treatments carried out to treat NPC. Salvage surgical treatment was the first line of treatment for residual or recurrent NPC (rNPC). Open-approach surgery was performed as the location of the nasopharynx is deep inside. These include

• Transpalatal.

• Transmandibular.

• Maxillary swing.

• Transinfratemporal.

These open approaches involve morbidity (condition of suffering from a disease). Advancements in endoscopic transnasal surgery have been achieved with endoscopic nasopharyngectomy for the treatment of rNPC at the primary site or advanced rNPC showing encouraging results.

What Are the Types of Nasopharynectomy?

Endoscopic transnasal pharyngotomy is divided into three types, as reported by P Castelneuvo. Types of nasopharyngeal endoscopic resection (NER) include; type 1, type 2, and type 3 NER. Type 1 and type 2 NER target rNPC located at the middle line of the base of the skull, nasal sinus, and nasopharynx. Type 3 NER extends laterally to the parapharyngeal space and ipsilateral cartilaginous portion of the eustachian tube. These types cannot be used in advanced rNPC.

Different types of transnasal endoscopic nasopharyngectomy (TEN) are introduced to treat advanced rNPC based on their latest staging system.TEN was classified into

• Type I TEN: It is used in the treatment of rNPC confined to the midline of the nasopharynx and skull base.

• Type II TEN: Resection extends laterally to the upper parapharyngeal space and cartilaginous portion of the eustachian tube.

• Type III TEN: Resection extends laterally to the infratemporal fossa, the bone portion of the eustachian tube, orbital and superior orbital fissure, the floor of the middle cranial fossa, cavernous sinus, pericranial nerve, and cervical spine.

• Type IV TEN: It targets the internal carotid artery (ICA) and intracranial rNPC following type III TEN.

What Are the Steps to Be Followed Before Endoscopic Nasopharyngectomy?

NPC is common cancer that occurs in the nasopharynx. Sometimes even after treatment, it is residual and recurs. To treat such conditions, endoscopic nasopharyngectomy is used.

The following steps are to be followed in this type of procedure:

• History: NPC can be diagnosed by the clinical history, which may include unilateral or bilateral enlarged lymph nodes in the neck, blood-tinged rhinorrhea (excess drainage from the nose), hearing loss, and headache.

• Physical Examination: Examination of the nasopharynx is done with a mirror or fiberoptic nasopharyngoscope to visualize the tumor mass. Direct visualization with an endoscope is also preferred. In the case of deep-seated rNPC, MRI is to be performed. Examination of the ear, neck, skull base and cranial nerves, oral cavity, pharynx, and larynx are done.

• Imaging: Magnetic resonance imaging (MRI) is done for superior soft tissue resolution and tumor description. Computed tomography (CT scan) is done to check the metastasis of the tumor.

What Are the Indications for Endoscopic Nasopharyngectomy?

Indications of endoscopic nasopharyngectomy include:

• In case of radiotherapy failure of rNPC.
• Lesions present at the center, roof, or floor of the nasopharynx, which has minimal lateral extension.
• Recurrent NPC with the involvement of skull base bone with the aid of navigation.

What Are the Contraindications of Endoscopic Nasopharyngectomy?

Contraindications of endoscopic nasopharyngectomy include:

• NPC involving para pharyngeal space or infratemporal fossa involvement.

• Contraindicated in salvage surgery.

• NPC with dural involvement and intracranial extension.

• If the involvement of ICA or cavernous sinus.

• If an individual is not fit for the surgery.

What Is the Preoperative Preparation of Endoscopic Nasopharyngectomy?

Preoperative preparation includes:

• Evaluation: Examinations are to be done by specialist doctors such as an otorhinolaryngologist, oncologist, anesthesiologist, nutritionist, and internal medicine specialist.

• Treatment of Sinusitis: If sinusitis is present, a bacterial culture is to be done to select the appropriate antibiotics. Frequent nasal douching is to be done with saline before surgery.

• Medications: Patients are instructed to discontinue taking the antiplatelet drugs.

What Is to Be Done During the Operative Period?

• Anesthesia: General anesthesia is given. An oral endotracheal tube is used. Temporary tracheostomy is to be done in severe cases of trismus. Anesthesia is to be monitored. Hydration and hemoglobin are to be maintained.

• Positioning: The individual should be in a supine position with the neck slightly extended. The nasal cavity is decongested with cotton pledges for 15 minutes. Observing the nasopharynx and cancer and its extent.

• Antibiotic Prophylaxis: Prophylactic intravenous antibiotics are to be given based on the bacterial culture. In case of longer surgery, additional doses can be given every six hours.

• Prerequisite Skill: Experience in skull base surgery and familiarity with anatomy is required. Sometimes patients should be ready for an open approach.

• Surgical Procedure: After intubation, intraoperative evaluation is done. Decongestion and anesthesia are checked. The extent of the lesion is assessed, and an endoscopic nasopharyngectomy is performed, during which the affected part of the nasopharynx is removed. It is performed in tumors that are small and not spread beyond the nasopharynx.

What Are the Risks Involved in the Procedure?

Risks are similar to that of skull base surgery, which includes:

• Intracranial hemorrhage.

• Pneumocranium (presence of air within brain parenchyma) or tension pneumocephalus.

• Leakage of cerebrospinal fluid (CSF).

Conclusion

Nasopharyngectomy is the treatment done for NPC. Carcinomas are challenging to treat. As the site of occurrence of NPC is behind the throat, endoscopic nasopharyngectomy is the treatment option, especially in recurrent cases. It is an effective and successful treatment. Knowing in detail about the procedure helps one to seek help from the healthcare provider at the earliest, which helps in effective treatment.