What Is Nasopharyngeal Carcinoma?

Nasopharyngeal carcinoma is a malignant tumor that occurs in the top and side walls of the nasopharynx. It is one of the most frequently-occurring malignant tumors in China. Common clinical symptoms are nasal congestion, blood in the snot, blocked ears, hearing loss, diplopia and headache. Most nasopharyngeal carcinomas have moderate sensitivity to radiation therapy, and radiation therapy is the first choice for nasopharyngeal carcinoma. However, in cases of highly differentiated cancers with a late course and recurrence after radiotherapy, surgical resection and chemotherapy are also indispensable.

Basic Information

English name

nasopharyngeal carcinoma, NPC

Visiting department

Otorhinolaryngology

Common locations

Nasopharyngeal cavity

Common causes

Familial aggregation, ethnic susceptibility, regional concentration, susceptible genes, viral infections, environmental factors

Common symptoms

Nasal congestion, blood in the nose, stuffiness in the ears, hearing loss, diplopia, headache

Contagious

no

Causes of nasopharyngeal cancer

The causes of nasopharyngeal cancer are many. Clinical observations and experimental studies over the years have shown that the following factors are closely related to the occurrence of nasopharyngeal carcinoma.

Genetic factor

(1) Family aggregation phenomenon Many patients with nasopharyngeal cancer have a family history of cancer. Nasopharyngeal carcinoma has a vertical and horizontal familial tendency.

(2) Racial susceptibility Nasopharyngeal carcinoma is mainly found in yellow people and rarely seen in white people; ethnic groups with a high incidence rate move elsewhere (or overseas Chinese), and their descendants still have a high incidence.

(3) Regional concentration Nasopharyngeal carcinoma mainly occurs in five provinces in southern China, namely Guangdong, Guangxi, Hunan, Fujian, and Jiangxi, and ranks first in local head and neck malignancies. Southeast Asian countries are also high incidence areas.

(4) Susceptibility genes In recent years, molecular genetic studies have found that chromosomal changes in nasopharyngeal carcinoma tumor cells are mainly chromosomes 1, 3, 11, 12, and 17. Polychromosomal heterozygosity is found in nasopharyngeal carcinoma tumor cells. Sexual deletion regions (1p, 9p, 9q, 11q, 13q, 14q, and 16q) may indicate that there are mutations in multiple tumor suppressor genes during the development of nasopharyngeal carcinoma.

2. virus infection

In 1964, Epstein and Barr first established a passivatable lymphoblast cell line from the biopsy tissue of African children's lymphoma (Burkitt lymphoma). Herpes-like virus particles can be seen under the electron microscope. Because it has different characteristics from other members of the herpes virus family, it is named Epstein-Barr virus, or EB virus.

Virus-like lymphoblastoid cell lines can be isolated from nasopharyngeal carcinoma tissues, and a few virus particles can be seen under an electron microscope. Immunological and biochemical studies have confirmed that EB virus is closely related to nasopharyngeal carcinoma. The dynamic changes and monitoring of EB virus antibody titers can be used as indicators for clinical diagnosis, estimation of prognosis and follow-up monitoring.

In addition to EB virus, other viruses such as coronavirus are also considered to be involved in the development of nasopharyngeal carcinoma.

3. Environmental factors

It has been reported that the nasopharyngeal cancer mortality rate among Chinese people who have migrated abroad has gradually decreased with the number of hereditary generations. Conversely, white people born in Southeast Asia have an increased risk of nasopharyngeal cancer. It is suggested that environmental factors may play an important role in the pathogenesis of nasopharyngeal carcinoma.

An epidemiological investigation found that babies in areas with high incidence of nasopharyngeal cancer in Guangdong Province had salted fish in their first food contact after weaning. In addition, dried fish and Cantonese flavor are also related to the incidence of nasopharyngeal cancer. These foods have nitrosamine precursors, nitrites, during the pickling process. When the pH value of human gastric juice is 1 to 3, nitrite or nitrate (which needs to be reduced to nitrite by cells) can synthesize nitrosamines with secondary amines in cells. These substances have a strong carcinogenic effect.

Certain trace elements, such as nickel, have excessive levels in the environment and may also induce nasopharyngeal cancer.

Clinical manifestations of nasopharyngeal carcinoma

Primary cancer

(1) Nosebleeds and nosebleeds If the lesion is located on the back wall of the nasopharynx, if the nasal cavity or nasopharyngeal secretion is sucked backwards, it can cause nosebleeds (ie, blood in the "sputum" when the nose is sucked). Severe cases can cause nosebleeds. Symptoms are common in tumors with ulcer or cauliflower type, while those with submucosal type are rare.

(2) Ear symptoms The tumor is in the crypt of the pharyngeal crypt or eustachian tube. Due to the infiltration of the tumor, the eustachian tube pharyngeal is compressed, and symptoms and signs of secretory otitis media appear: tinnitus, hearing loss, etc. Pharyngeal cancer patients were found due to ear symptoms.

(3) Nasal symptoms Infiltration of the primary cancer into the posterior nostril area can cause mechanical blockage, and tumors located in the anterior wall of the nasopharynx are more likely to cause nasal congestion. Nasal congestion accounted for 15.9% of the first symptoms and 48.0% at the time of diagnosis.

(4) Headache is a common symptom. Clinical manifestations are mostly unilateral persistent pain, mostly in the temporal and apical parts.

(5) Ocular symptoms Although nasopharyngeal cancer invades the orbit or nerves associated with the eyeballs, although it is advanced, some patients still see this symptom.

Nasopharyngeal cancer invades the eyes and often causes the following symptoms and signs: visual impairment (blindness), visual field loss, diplopia, exophthalmos and restricted movement, and neuroparalytic keratitis. Fundus examination showed optic nerve atrophy and edema.

(6) Symptoms of Cerebral Nerve Damage In the process of nasopharyngeal cancer infiltration around the trigeminal nerve, abductor nerve, glossopharyngeal nerve, and sublingual nerve, the olfactory nerve, facial nerve, and auditory nerve are less affected.

(7) Neck lymph node metastasis: Neck enlarged lymph nodes are painless and hard. They can move in the early stage, and adhere to the skin or deep tissue in the later stage to fix.

(8) Distant metastasis In individual cases, distant metastasis is the main complaint.

(9) Cachexia can die from systemic organ failure, and some die from sudden major bleeding.

2. Nasopharyngeal carcinoma with dermatomyositis

Dermatomyositis is a serious connective tissue disease. The relationship between malignant tumors and dermatomyositis is not clear, but the incidence of malignant tumors in patients with dermatomyositis is at least five times higher than that in normal people. Therefore, patients with dermatomyositis need to undergo a careful whole body examination to find hidden malignant tumors.

3. Recessive nasopharyngeal carcinoma

Swollen lymph nodes in the neck have been confirmed as metastatic cancer by pathological sectioning. However, multiple examinations or biopsies of each suspicious site have not found the primary cancer lesions, which are called hidden cancer of the head and neck (the primary tumors are located in the chest, abdomen or Pelvic patients do not fall into this category).

Nasopharyngeal cancer examination

Anterior rhinoscopy

A small number of cases can be found after the invasion of new organisms into the nostrils, mostly granulation tissue.

2. Nasopharyngoscopy

Very important for diagnosis.

(1) Indirect nasopharyngoscopy. Care must be taken repeatedly to look for suspicious areas. Those who are unable to cooperate with the sensitive examination of the pharynx can be examined after surface anesthesia; if it is still unsuccessful, the soft palate can be opened with a soft palate hook, or a thin catheter Insert the front nostril, the front end is pulled out from the mouth, and the rear end is left outside the front nostril. The two ends are fastened and fixed, and the soft palate is pulled forward, which can fully expose the nasopharynx and allow biopsy.

(2) Nasopharyngeal fiberscope or electronic nasopharyngeal fiberscope. A flexible flexible fiberoptic fiberscope. Introduced from the nasal cavity (after surface anesthesia), the nasopharynx can be fully and carefully observed, and photography, video and biopsy are feasible. It is the most effective modern tool for examining the nasopharynx.

3. Pathological examination

(1) Biopsy can take the nasal route or the oral route. If the biopsy is negative, repeat the procedure for those who still feel suspicious and follow up closely.

(2) Cervical lymph node excision biopsy or cervical lymph node cytology puncture smear. If cervical lymph nodes are enlarged and hard, cervical lymph node puncture smear should be performed. If there is no obvious suspicious lesion in the nasopharynx, lymph node biopsy must be considered.

(3) Cytological diagnosis of nasopharyngeal detachment Appropriate materials, immediate fixation, staining and examination can supplement the shortcomings of biopsy. The following situations are more suitable for this examination: regular inspection during the treatment process to dynamically observe the efficacy; for patients with occult cancer, materials can be taken from multiple locations for examination; used for mass census.

(4) Fine needle aspiration cytology (FNA) examination FNA is very valuable in the diagnosis of metastatic nasopharyngeal carcinoma, such as cervical lymph node involvement. This method can be used to evaluate the primary tumor. It has the advantages of safety, simplicity, fast and reliable results.

4.CT scan

CT scans have a high resolution, which can not only show the changes in the surface structure of the nasopharynx, but also show the infiltration of nasopharyngeal cancer into the surrounding structure and the parapharyngeal space. It also shows the invasion of the skull base and intracranial invasion. Clearer and more accurate.

5. Magnetic resonance (MRI) examination

MRI has a higher resolution of soft tissue than CT. MRI can determine the location and extent of the tumor and the invasion of adjacent structures. MRI has a unique effect on nasopharyngeal carcinoma that recurs after radiotherapy. It can identify tissue fibrosis and recurrent tumors after radiotherapy. Recurrent tumors are irregularly lumpy and may be accompanied by invasion of adjacent bone or (and) soft tissue structures and lymphadenopathy. After radiotherapy, the fibrosis showed a localized thickening or a limited irregular patchy structure, and the boundary between it and the adjacent tissues was unclear. On the T1-weighted image, the recurring tumors and fibrotic tissues showed low signals; on the T2-weighted image, the recurring tumors were high signals, and fibrous tissue showed low signals.

6. EBV shell antigen-IgA antibody detection

The EB virus shell antigen-IgA antibody (VCA-IgA antibody) increased most significantly in the serum of patients with nasopharyngeal carcinoma. At present, immunoenzyme is widely used in China.

Nasopharyngeal cancer diagnosis

Early detection and early diagnosis are the most important. Whether early detection and early diagnosis are closely related to the following points:

1. The primary site of the tumor and the growth mode of the tumor (exogenous or submucosal development to the deep).

2. In clinical work, if you experience symptoms of progressive eustachian tube obstruction on one side for unknown reasons; blood in your nose or blood in "phlegm" after sucking nose; cervical lymphadenopathy; headache of unknown cause; Patients with abducent nerve palsy and the like should take into account the possibility of nasopharyngeal cancer and conduct a detailed examination.

3. The patient himself lacked knowledge of nasopharynx and delayed diagnosis without going to the hospital in time.

Differential diagnosis of nasopharyngeal carcinoma

1. Other malignant tumors of the nasopharynx (such as lymphosarcoma)

Lymphosarcoma occurs in young people. The primary tumor is large and often has severe nasal congestion and ear symptoms. The lymph node metastasis is not limited to the neck. Multiple lymph nodes throughout the body can be affected. The cranial nerve damage is not as good as that of the nasopharynx. Cancer is common and pathological diagnosis is needed in the end.

2. Nasopharyngeal tuberculosis

Most patients had a history of tuberculosis, in addition to nasal obstruction and hemorrhagic blood, as well as low fever, night sweats, weight loss and other symptoms. Examination showed nasal ulcers, edema, and pale color. Secretion smears can find acid-fast bacilli, which can be accompanied by cervical lymph node tuberculosis; lymph nodes are swollen, adhesions, and no tenderness; cervical lymph node puncture can find tuberculosis bacteria; PPD test is strongly positive. X-ray chest radiographs often suggest active pulmonary tuberculosis.

3. Proliferative lesions

There are single or multiple nodules on the nasopharyngeal parietal wall, posterior parietal wall, or parietal lateral wall. The bulges are as small as hillocks, and the size is 0.5cm to 1cm. Occurred on the basis of the sample body, it can also be caused by keratinized epithelium retention and formation of epidermoid cysts after the squamous metaplasia of the mucosal epithelium, part of which is the strong secretion of mucosal glands and the formation of retention cysts. When the mucosa on the surface of the nodule appears rough, eroded, ulcerated, or bleeding, the possibility of canceration needs to be considered, and a biopsy should be performed to confirm the diagnosis.

4. Other

Nasopharyngeal carcinoma also needs to be distinguished from nasopharyngeal fibrous hemangiomas, parapharyngeal space tumors, neck and intracranial tumors (such as craniopharyngioma, chordoma, and cerebellopontine angle tumors).

Nasopharyngeal Cancer Treatment

Most nasopharyngeal carcinomas have moderate sensitivity to radiation therapy, and radiation therapy is the first choice for nasopharyngeal carcinoma. However, in cases of highly differentiated cancers with a late course and recurrence after radiotherapy, surgical resection and chemotherapy are also indispensable.

Radiation therapy

(1) Indications and contraindications for radiotherapy for nasopharyngeal carcinoma Indications for radical radiotherapy: Moderate or above general body condition; no obvious bone destruction at the skull base; CT or MRI shows no or only mild or moderate paranasal and pharyngeal cancer Those with moderate infiltration; those with cervical lymph nodes with a maximum diameter of less than 8 cm and who have not reached the supraclavicular fossa; those with no distant organ metastasis. Indications for palliative radiotherapy: The tumor has a KSP grade of 60 or higher; severe headache, moderate or more bleeding in the nasopharynx; patients with a single distant metastasis or cervical lymph node metastasis greater than 10 cm. If the general condition improves after palliative radiation, the symptoms disappear, and those with distant metastases can be controlled by radical radiation therapy. Contraindications for radiation therapy: KSP grade of tumor below 60 points; those with extensive distant metastasis; those with acute infection; those with radiation-induced cerebral spinal cord injury . The principle of re-radiotherapy. The principle of re-radiation after radiation therapy is not suitable for those who have the following conditions: the same target area including the nasopharyngeal and neck target areas has not recurred after radiotherapy; radiation encephalopathy or radiation spinal cord appears after radiation treatment The total target course of nasopharynx should not exceed three courses, and the target area of neck should not exceed two courses.

(2) Selection of radiation Since the primary site of nasopharyngeal carcinoma is deep and surrounded by overlapping bones, high-energy radiation sources such as ⁶⁰ cobalt or linear accelerators with strong penetration, low skin volume and low absorption should be selected. High-energy X-ray. Among these two devices, the accelerator is superior, because the penumbra produced by the two devices is very small, the deep dose is high and uniform, and the surrounding normal tissue is less damaged, and the effect is better. For external tumors after external irradiation, X-ray body lumen or post-loading cavity can be used for supplementary treatment.

(3) Radiation dose and time External irradiation can be performed by continuous method or segmented method. Although the long-term effects of the two methods are similar, the former has a shorter total time and the response is heavier after radiotherapy; the latter has a longer total radiation time, but has a lighter response after radiotherapy.

(4) Design of the radiation field The radiation field of each case needs to include the nasopharynx and its adjacent sinus cavity, space, skull base and neck. However, do not overlap or omit the dose between the irradiation fields. In principle, all parts of the body should be irradiated at the same time. However, if the patient has severe headaches, nosebleeds, etc., he can be irradiated with Ono first to reduce the symptoms, and then irradiated according to the full field.

(5) New radiotherapy technologies in recent years Intracavity brachytherapy The commonly used radiation sources are ¹⁹² iridium and ¹³⁷ cesium. The biggest advantage of brachytherapy is that it can increase the local radiation dose in the target area and reduce the surrounding normal tissues. Radiation damage. Brachytherapy is usually used as a supplement to external radiation. Clinical studies in recent years have shown that the local control rate of localized superficial lesions of the nasopharynx is improved to some extent compared with conventional external exposure alone. Gamma Knife Treatment Gamma Knife is a multi-beam gamma ray therapy device with three-dimensional stereotactic high-energy focusing. After the tumor is accurately located, the tumor can be destroyed in a single shot with a large dose of radiation. The damage to surrounding normal tissues is minimal. Cases of nasopharyngeal carcinoma that recur after radiation therapy are suitable for gamma knife treatment. The first case of nasopharyngeal carcinoma should be treated with a gamma knife with caution, as its long-term effect on nasopharyngeal carcinoma needs further observation. Three-dimensional conformal radiotherapy Three-dimensional conformal radiotherapy is one of the most important advances in tumor radiotherapy in recent years. It can distribute the radiation dose to the target area more evenly according to the different shapes of the tumor. Conformal emphasis on radiotherapy Conformal emphasis on radiotherapy is a new radiotherapy technology developed in recent years. This technology can grant different irradiation doses to different target areas according to the size, shape and biological behavior of different tumors, and at the same time has unique protective advantages for important organs around the tumor.

(6) Complications of radiotherapy Systemic reactions include fatigue, dizziness, decreased appetite, nausea, vomiting, tastelessness or odor in the mouth, insomnia, or lethargy. Hematological changes can occur in individual patients, especially with reduced white blood cell counts. Although the degrees are different, they can usually be overcome after symptomatic treatment and radiation therapy can be completed. If necessary, you can take vitamin B ₁ , B ₆ , C, metoclopramide and so on. If the white blood cell count drops below 3 × 10 ⁹ / L, radiotherapy should be suspended. Local reactions include skin, mucous membrane, and salivary gland reactions. The skin reaction manifests as dry dermatitis or even wet dermatitis, and an anti-inflammatory ointment based on 0.1% borneol talc or lanolin can be used topically. The mucosal reaction manifests as nasopharyngeal and oropharyngeal mucosa congestion, edema, exudation and accumulation of secretions, etc. Topical use of gargles and lubricating anti-inflammatory agents is possible. In a few patients, parotid swelling can occur after 2Gy irradiation of parotid glands, and swelling gradually decreases in 2 to 3 days. When irradiated with 40 Gy, saliva secretion was significantly reduced, while oral mucosa secretion increased, and mucosal congestion and swelling. The patient had a dry mouth and had difficulty eating dry food. Therefore, avoid excessive exposure to the parotid glands. Regression to radiation therapy mainly includes temporomandibular joint dysfunction and soft tissue atrophy and fibrosis, radiation caries, radiation jaw osteomyelitis, and radiation cerebrospinal disease. At present, there is no proper way to reverse, and symptomatic treatment and support methods will help. We must strictly avoid overexposure of important tissues and organs.

2. Chemotherapy

Mainly used in middle and advanced cases. Those who fail to control and relapse after radiotherapy are an adjunct or palliative treatment. There are three common methods of administration:

(1) Systemic chemotherapy can be administered orally, intramuscularly, or intravenously. Commonly used drugs are nitrogen mustard, cyclophosphamide, 5-fluorouracil, bleomycin, and stipate. They can be used alone or in combination.

(2) Half-body chemotherapy is a method of compressing the abdominal aorta, temporarily blocking blood circulation in the lower body, and quickly injecting nitrogen mustard from the veins of the upper limbs. The nitrogen mustard is injected into the body 2 to 3 minutes later, and the effect can be reduced by 15 minutes. It can not only increase the drug concentration in the upper body, but also protect the hematopoietic function of the lower body bone marrow.

Contraindications for half-body chemotherapy: patients with hypertension, heart disease; elderly, frail, and obese; patients with superior vena cava compression; patients with cirrhosis and hepatomegaly; patients with severely impaired liver and kidney function; white blood cell count below 3 × 10 ⁹ / L.

(3) Arterial intubation chemotherapy can increase drug concentration in the nasopharynx and reduce systemic side effects. Superficial temporal or facial arteries were retrogradely cannulated to inject anticancer drugs. For early (stage I, II) cases involving a single small upper cervical deep lymph node metastasis case, late cases with cerebral nerve involvement, or local residual or recurrent cases of nasopharyngeal after radiotherapy, there are certain short-term effects. Commonly used anticancer drugs are 5-fluorouracil, pingyangmycin, and cisplatin.

3. Combined radiotherapy and chemotherapy

For advanced nasopharyngeal cancer can be combined with radiation and chemical treatment. There are reports in the literature: the effect of combined treatment is significantly better than single treatment.

4. Surgery

(1) Indications Non-primary treatment methods, only in a few cases. The indications are as follows: those with localized lesions in the nasopharynx do not subside or relapse after radiotherapy. Neck metastatic lymph nodes, which do not subside after radiotherapy, show active solitary encapsulation, and those with primary nasopharyngeal lesions have been controlled. Neck dissection is feasible.

(2) Contraindications : Skull base bone destruction or nasopharyngeal infiltration, brain nerve damage or distant metastasis. Those with poor general conditions or poor liver and kidney function. There are other contraindications to surgery.

5. Immunotherapy

There are interferon inducers, phytohemagglutinin-tumor vaccine and so on. It is still in the exploratory stage.

Nasopharyngeal carcinoma prognosis

Nasopharyngeal carcinoma is mainly radiotherapy, and the remaining lesions can be surgically removed. The irradiation range includes the nasopharynx, skull base, neck and orbit. The primary fossil dose was 65 to 70 Gy, and the secondary foci were 50 to 60 Gy. The prognosis is poor due to tumor recurrence and early metastasis. The 5-year survival rate of radiation-insensitive squamous cell carcinoma is 0% to 10%, and the 5-year survival rate of radiation-sensitive lymphoepithelial carcinoma is about 30%.