Nasopharyngeal carcinoma
Encyclopedia
Nasopharyngeal carcinoma (NPC) is the most common cancer
originating in the nasopharynx
, the uppermost region of the pharynx
("throat"), behind the nose where the nasal passages
and auditory tubes
join the remainder of the upper respiratory tract
. NPC differs significantly from other cancers of the head and neck
in its occurrence
, causes
, clinical behavior, and treatment. It is vastly more common in certain regions of East Asia
and Africa
than elsewhere, with viral
, diet
ary and genetic
factors implicated in its causation. It is most common in males. It is a squamous cell carcinoma or an undifferentiated type. Squamous cells are a flat type of cell found in the skin and the membranes that line some body cavities. Differentiation means how different the cancer cells are from normal cells. Undifferentiated is a word used to describe cells that do not have their mature features or functions.
, or cancer
, arising from the mucosal epithelium
of the nasopharynx
, most often within the lateral nasopharyngeal recess or fossa of Rosenmüller (the space behind the nose). The World Health Organization Classifies Nasopharyngeal Carcnioma in three types. Type 1 (I) is squamous cell carcinoma. Type 2a (II) is keratinizing undifferentiated carcinoma. Type 2b (III) is nonkeratinizing undifferentiated carcinoma. Type 2b (III) nonkeratinizing undifferentiated form is most common, and is most strongly associated with Epstein-Barr virus
infection of the cancerous cells.
In Summary:
Stage I small tumor confined to nasopharynx
Stage II tumor extending in the local area or any evidence of limited neck (nodal) disease
Stage III a large tumor with or without neck disease, or a tumor with bilateral neck disease
Stage IV intracranial or infratemporal involvement of tumor, extensive neck disease, or any distant metastasis
. Symptoms related to the primary tumor include trismus
, pain, otitis media
, nasal regurgitation due to paresis
(loss of or impaired movement) of the soft palate, hearing loss and cranial nerve palsies (paralysis). Larger growths may produce nasal obstruction or bleeding and a "nasal twang". Metastatic spread
may result in bone pain or organ dysfunction. Rarely, a paraneoplastic syndrome
of osteoarthropathy (diseases of joints and bones) may occur with widespread disease.
)
NPC is the most common epithelial cancer in adults. The detection of nuclear antigen associated with Epstein-Barr virus (EBNA) and viral DNA in NPC type 2 and 3, has revealed that EBV can infect epithelial cells and is associated with their transformation. The etiology
of NPC (particularly the endemic form) seems to follow a multi-step process, in which EBV, ethnic background, and environmental carcinogen
s all seem to play an important role. Lo et al. showed that EBV DNA was detectable in the blood plasma
samples of 96% of patients with non-keratinizing NPC, compared with only 7% in controls [9]. More importantly, EBV DNA levels appear to correlate (have a relationship) with treatment response and they may predict disease recurrence, suggesting that they may be an independent indicator of prognosis. In adults, other likely etiological
factors include genetic susceptibility, consumption of food (in particular salted fish) containing carcinogenic volatile nitrosamines, and as in children, EBV .
Due to the anatomical position of NPC and its tendency to present with cervical lymph node metastases, it is not amenable to surgery for local control. Biopsy of the involved lymph node is the usual surgical procedure. The nasopharyngeal primary tumor is rarely biopsied.
Chemotherapy.
Several factors are taken into account in deciding the chemotherapy regimen.
Firstly, efficacy(ability to get the desired result): the figures for event-free survival are similar for most small chemotherapy series but therapy usually involves fairly high-dose radiotherapy to the nasopharynx – 60 to 65 Gy. However, the most promising results with a recent update, are those obtained using the Mertens protocol NPC-91-GPOH (Society of Pediatric Oncology and Hematology). This protocol should therefore be considered as the best current treatment. Uniquely, the NPC-91-GPOH protocol includes immunotherapy with interferon-beta after chemotherapy and radiotherapy, which may explain its superior results compared to regimens without interferon treatment .
Secondly, late effect
s: in terms of chemotherapy, the Manchester regimen – doxorubicin, methotrexate and cyclophosphamide – would produce infertility in boys (total dose of cyclophosphamide 12 gm/m2) and possible anthracycline toxicity (total dose of doxorubicin 360 mg/m2) [36]. The NPC-91-GPOH protocol might produce some infertility in older boys but the total dose of cisplatinum is only 300 mg/m2. Furthermore, the incidence of renal toxicity should be relatively low but auditory toxicity would be higher because of the additional effect of irradiation on the auditory apparatus. The degree of pituitary gland
dysfunction obviously depends on the radiotherapy field and, potentially, on the dose of radiotherapy but some degree of hypopituitarism
is expected. Furthermore, irradiation to the neck would result in hypothyroidism for the majority of patients and irradiation
to the oropharynx would result in xerostomia (dry mouth) and resultant poor dentition. The later may be relieved by amifostine, as demonstrated in adult studies.
Radiotherapy.
Although treatment with radiotherapy controls the primary tumor [28-30], it does not prevent the appearance of distant metastases [28,31].
Radiotherapy is given with megavoltage equipment after initial chemotherapy. A maximum dose of 45 Gy is given to the clinical target volume, which is a 1 cm margin around the MRI-detected primary site, and inferiorly (below) down to the clavicle
s (collar bone) to include the lymph node
s. Treatment is given in two phases:
Recommendation.
In the current GPOH protocol NPC-2003-GPOH, low-risk patients with Stage I and II tumors receive radiotherapy only, followed by 105 μg/Kg of adjuvant interferon beta (IFNbeta), intravenously (i.v.), three times a week for 6 months. High-risk patients receive cisplatinum (100 mg/m2 over 6 hours on day 1 with standard hydration), mannitol and electrolyte replacement, and folinic acid (25 mg/m2 every 6 hours for a total of six doses) as well as 5-fluorouracil (1000 mg/m2 per day from day 2 for 5 days) as a continuous infusion. They receive three courses of chemotherapy every 21 days or on full blood count
recovery, followed by irradiation and IFNbeta as for low-risk patients. Methotrexate has been dropped because of severe mucositis. Patients not in CR after three courses of chemotherapy will receive concomitant cisplatinum (20 mg/m2/day for 3 days with radiotherapy for two courses).
Stage at presentation is the most prognostic factor.
The 5-year disease-specific survival (DSS) is as follow:
• For stage I à 98%
• For stage II A-B à 95%
• For stage III à 86%
• For stage IV A-B à 73% (…)
Factors that may influence prognosis include the clinical stage, patient age and gender, presence of keratinization, lymph node metastasis, and possibly genetic factors.
• Better prognosis is associated with lower clinical stage, younger patient age, and female gender.
• While worse prognosis is seen with high-stage tumors, old patients and male gender(..)
Presentation with lymphadenomegalia implies that the disease has spread beyond the primary site. However, in childhood the presence of metastatic disease in cervical lymph nodes at diagnosis does not adversely affect prognosis (likely outcome) [30-33].
Factors associated with a poor prognosis
• skull base involvement [33-35]
• extent of the primary tumor [31,32]
• cranial nerve involvement [33,34]
Reddy et al. (..) evaluated 50 patients with NPC and found that the patients with the keratinizing type of NPC had a higher incidence of locally advanced tumor but a lower incidence of lymphatic and/or distant spread. Despite these findings, the patient with the keratinizing NPC had a poorer 5-year survival rate than those with the other histologic subtypes due to a higher incidence of deaths secondary to local uncontrollable disease and nodal metastasis. (…) NPC frequently metastasize to regional lymph nodes and the presence of lymph node metastasis decrease survival by 10-20%.(..)
Similarly, a large percentage of NPC, particularly of the undifferentiated type, metastasize to sites below the clavicle, including lung, bones (rib and spine), and liver.
and most other nations, but is extremely common in southern regions of China, particularly in Guangdong
accounting for 18% of all cancers in China
. It is sometimes referred to as Cantonese cancer because it occurs in about 25 cases per 100,000 people in this region, 25 times higher than the rest of the world. It is also quite common in Taiwan
. This could be due to the South East Asian diet which typically includes consumption of salted vegetables, fish and meat. While NPC is seen primarily in middle-aged persons in Asia
, a high proportion of Africa
n cases appear in children. The cause of increased risk for NPC in these endemic
regions is not entirely clear.
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
originating in the nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
, the uppermost region of the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
("throat"), behind the nose where the nasal passages
Nasal cavity
The nasal cavity is a large air filled space above and behind the nose in the middle of the face.- Function :The nasal cavity conditions the air to be received by the other areas of the respiratory tract...
and auditory tubes
Eustachian tube
The Eustachian tube is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately 35 mm long. It is named after the sixteenth-century anatomist Bartolomeo Eustachi...
join the remainder of the upper respiratory tract
Upper respiratory tract
The upper respiratory tract or upper airway primarily refers to the parts of the respiratory system lying outside of the thorax or above the sternal angle. Another definition commomly used in medicine is the airway above the glottis or vocal cords...
. NPC differs significantly from other cancers of the head and neck
Head and neck cancer
Head and neck cancer refers to a group of biologically similar cancers that start in the upper aerodigestive tract, including the lip, oral cavity , nasal cavity , paranasal sinuses, pharynx, and larynx. 90% of head and neck cancers are squamous cell carcinomas , originating from the mucosal lining...
in its occurrence
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
, causes
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
, clinical behavior, and treatment. It is vastly more common in certain regions of East Asia
East Asia
East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...
and Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
than elsewhere, with viral
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
, diet
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...
ary and genetic
Human genetics
Human genetics describes the study of inheritance as it occurs in human beings. Human genetics encompasses a variety of overlapping fields including: classical genetics, cytogenetics, molecular genetics, biochemical genetics, genomics, population genetics, developmental genetics, clinical genetics,...
factors implicated in its causation. It is most common in males. It is a squamous cell carcinoma or an undifferentiated type. Squamous cells are a flat type of cell found in the skin and the membranes that line some body cavities. Differentiation means how different the cancer cells are from normal cells. Undifferentiated is a word used to describe cells that do not have their mature features or functions.
Classification
Nasopharyngeal carcinoma, commonly known as nasopharyngeal cancer, is classified as a malignant neoplasmNeoplasia
Neoplasm is an abnormal mass of tissue as a result of neoplasia. Neoplasia is the abnormal proliferation of cells. The growth of neoplastic cells exceeds and is not coordinated with that of the normal tissues around it. The growth persists in the same excessive manner even after cessation of the...
, or cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, arising from the mucosal epithelium
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
of the nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
, most often within the lateral nasopharyngeal recess or fossa of Rosenmüller (the space behind the nose). The World Health Organization Classifies Nasopharyngeal Carcnioma in three types. Type 1 (I) is squamous cell carcinoma. Type 2a (II) is keratinizing undifferentiated carcinoma. Type 2b (III) is nonkeratinizing undifferentiated carcinoma. Type 2b (III) nonkeratinizing undifferentiated form is most common, and is most strongly associated with Epstein-Barr virus
Epstein-Barr virus
The Epstein–Barr virus , also called human herpesvirus 4 , is a virus of the herpes family and is one of the most common viruses in humans. It is best known as the cause of infectious mononucleosis...
infection of the cancerous cells.
Staging
Staging of Nasophayngeal Carcinoma is based on clinical and radiologic examination. Most patients present with Stage III or IV disease.In Summary:
Stage I small tumor confined to nasopharynx
Stage II tumor extending in the local area or any evidence of limited neck (nodal) disease
Stage III a large tumor with or without neck disease, or a tumor with bilateral neck disease
Stage IV intracranial or infratemporal involvement of tumor, extensive neck disease, or any distant metastasis
Symptoms and signs
Cervical lymphadenopathy (disease or swelling of the lymph nodes in the neck) is the initial presentation in many patients, and the diagnosis of NPC is often made by lymph node biopsyBiopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
. Symptoms related to the primary tumor include trismus
Trismus
-Common causes:*Pericoronitis is the most common cause of trismus.*Inflammation of muscles of mastication. It is a frequent sequel to surgical removal of mandibular third molars . The condition is usually resolved on its own in 10–14 days, during which time eating and oral hygiene are compromised...
, pain, otitis media
Otitis media
Otitis media is inflammation of the middle ear, or a middle ear infection.It occurs in the area between the tympanic membrane and the inner ear, including a duct known as the eustachian tube. It is one of the two categories of ear inflammation that can underlie what is commonly called an earache,...
, nasal regurgitation due to paresis
Paresis
Paresis is a condition typified by partial loss of voluntary movement or by impaired movement. When used without qualifiers, it usually refers to the limbs, but it also can be used to describe the muscles of the eyes , the stomach , and also the vocal cords...
(loss of or impaired movement) of the soft palate, hearing loss and cranial nerve palsies (paralysis). Larger growths may produce nasal obstruction or bleeding and a "nasal twang". Metastatic spread
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
may result in bone pain or organ dysfunction. Rarely, a paraneoplastic syndrome
Paraneoplastic syndrome
A paraneoplastic syndrome is a disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer cells. These phenomena are mediated by humoral factors excreted by tumor cells or by an immune response against the tumor...
of osteoarthropathy (diseases of joints and bones) may occur with widespread disease.
Causes
EBV (Epstein-Barr virusEpstein-Barr virus
The Epstein–Barr virus , also called human herpesvirus 4 , is a virus of the herpes family and is one of the most common viruses in humans. It is best known as the cause of infectious mononucleosis...
)
NPC is the most common epithelial cancer in adults. The detection of nuclear antigen associated with Epstein-Barr virus (EBNA) and viral DNA in NPC type 2 and 3, has revealed that EBV can infect epithelial cells and is associated with their transformation. The etiology
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
of NPC (particularly the endemic form) seems to follow a multi-step process, in which EBV, ethnic background, and environmental carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
s all seem to play an important role. Lo et al. showed that EBV DNA was detectable in the blood plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
samples of 96% of patients with non-keratinizing NPC, compared with only 7% in controls [9]. More importantly, EBV DNA levels appear to correlate (have a relationship) with treatment response and they may predict disease recurrence, suggesting that they may be an independent indicator of prognosis. In adults, other likely etiological
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
factors include genetic susceptibility, consumption of food (in particular salted fish) containing carcinogenic volatile nitrosamines, and as in children, EBV .
Treatment
Surgery.Due to the anatomical position of NPC and its tendency to present with cervical lymph node metastases, it is not amenable to surgery for local control. Biopsy of the involved lymph node is the usual surgical procedure. The nasopharyngeal primary tumor is rarely biopsied.
Chemotherapy.
Several factors are taken into account in deciding the chemotherapy regimen.
Firstly, efficacy(ability to get the desired result): the figures for event-free survival are similar for most small chemotherapy series but therapy usually involves fairly high-dose radiotherapy to the nasopharynx – 60 to 65 Gy. However, the most promising results with a recent update, are those obtained using the Mertens protocol NPC-91-GPOH (Society of Pediatric Oncology and Hematology). This protocol should therefore be considered as the best current treatment. Uniquely, the NPC-91-GPOH protocol includes immunotherapy with interferon-beta after chemotherapy and radiotherapy, which may explain its superior results compared to regimens without interferon treatment .
Secondly, late effect
Late effect
In medicine, a late effect is a condition that appears after the acute phase of an earlier, causal condition has run its course. A late effect can be caused directly by the earlier condition, or indirectly by the treatment for the earlier condition. Some late effects can occur decades later...
s: in terms of chemotherapy, the Manchester regimen – doxorubicin, methotrexate and cyclophosphamide – would produce infertility in boys (total dose of cyclophosphamide 12 gm/m2) and possible anthracycline toxicity (total dose of doxorubicin 360 mg/m2) [36]. The NPC-91-GPOH protocol might produce some infertility in older boys but the total dose of cisplatinum is only 300 mg/m2. Furthermore, the incidence of renal toxicity should be relatively low but auditory toxicity would be higher because of the additional effect of irradiation on the auditory apparatus. The degree of pituitary gland
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...
dysfunction obviously depends on the radiotherapy field and, potentially, on the dose of radiotherapy but some degree of hypopituitarism
Hypopituitarism
Hypopituitarism is the decreased secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain...
is expected. Furthermore, irradiation to the neck would result in hypothyroidism for the majority of patients and irradiation
Irradiation
Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve a specific purpose, rather than radiation exposure to...
to the oropharynx would result in xerostomia (dry mouth) and resultant poor dentition. The later may be relieved by amifostine, as demonstrated in adult studies.
Radiotherapy.
Although treatment with radiotherapy controls the primary tumor [28-30], it does not prevent the appearance of distant metastases [28,31].
Radiotherapy is given with megavoltage equipment after initial chemotherapy. A maximum dose of 45 Gy is given to the clinical target volume, which is a 1 cm margin around the MRI-detected primary site, and inferiorly (below) down to the clavicle
Clavicle
In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally...
s (collar bone) to include the lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s. Treatment is given in two phases:
- Phase I – parallel pair (mostly lateral unless the tumor extends anteriorly between the eyes). Eyes, brain and brain stem are shielded as much as possible. A mid-plane dose of 30 Gy in 15 fractions is given.
- Phase II – a lateral parallel pair or three-fields technique is used for the primary site, delivering 15 Gy in seven fractions to the clinical target volume of the tumor with a 1 cm margin. Brain stem and eyes should be shielded. Any overlap with the neck field should be shielded. A matching anterior neck node field is used to deliver a prescribed maximum subcutaneous (tissue underneath the outere layers of skin) dose of 15 Gy in seven fractions. The spinal cord should be shielded in this field. This prescription for radiotherapy is used in Manchester, but it is recognized that higher doses may be used in some centers, possibly to a total of 60 Gy to the tumor volume. In an current GPOH study, patients in complete remission (CR) after three courses of chemotherapy, will have their radiotherapy dosage reduced to 54 Gy instead of 59 Gy.
Recommendation.
In the current GPOH protocol NPC-2003-GPOH, low-risk patients with Stage I and II tumors receive radiotherapy only, followed by 105 μg/Kg of adjuvant interferon beta (IFNbeta), intravenously (i.v.), three times a week for 6 months. High-risk patients receive cisplatinum (100 mg/m2 over 6 hours on day 1 with standard hydration), mannitol and electrolyte replacement, and folinic acid (25 mg/m2 every 6 hours for a total of six doses) as well as 5-fluorouracil (1000 mg/m2 per day from day 2 for 5 days) as a continuous infusion. They receive three courses of chemotherapy every 21 days or on full blood count
Complete blood count
A complete blood count , also known as full blood count or full blood exam or blood panel, is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood...
recovery, followed by irradiation and IFNbeta as for low-risk patients. Methotrexate has been dropped because of severe mucositis. Patients not in CR after three courses of chemotherapy will receive concomitant cisplatinum (20 mg/m2/day for 3 days with radiotherapy for two courses).
Prognosis
Prognostic factorsStage at presentation is the most prognostic factor.
The 5-year disease-specific survival (DSS) is as follow:
• For stage I à 98%
• For stage II A-B à 95%
• For stage III à 86%
• For stage IV A-B à 73% (…)
Factors that may influence prognosis include the clinical stage, patient age and gender, presence of keratinization, lymph node metastasis, and possibly genetic factors.
• Better prognosis is associated with lower clinical stage, younger patient age, and female gender.
• While worse prognosis is seen with high-stage tumors, old patients and male gender(..)
Presentation with lymphadenomegalia implies that the disease has spread beyond the primary site. However, in childhood the presence of metastatic disease in cervical lymph nodes at diagnosis does not adversely affect prognosis (likely outcome) [30-33].
Factors associated with a poor prognosis
• skull base involvement [33-35]
• extent of the primary tumor [31,32]
• cranial nerve involvement [33,34]
Reddy et al. (..) evaluated 50 patients with NPC and found that the patients with the keratinizing type of NPC had a higher incidence of locally advanced tumor but a lower incidence of lymphatic and/or distant spread. Despite these findings, the patient with the keratinizing NPC had a poorer 5-year survival rate than those with the other histologic subtypes due to a higher incidence of deaths secondary to local uncontrollable disease and nodal metastasis. (…) NPC frequently metastasize to regional lymph nodes and the presence of lymph node metastasis decrease survival by 10-20%.(..)
Similarly, a large percentage of NPC, particularly of the undifferentiated type, metastasize to sites below the clavicle, including lung, bones (rib and spine), and liver.
Epidemiology
NPC is uncommon in the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and most other nations, but is extremely common in southern regions of China, particularly in Guangdong
Guangdong
Guangdong is a province on the South China Sea coast of the People's Republic of China. The province was previously often written with the alternative English name Kwangtung Province...
accounting for 18% of all cancers in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. It is sometimes referred to as Cantonese cancer because it occurs in about 25 cases per 100,000 people in this region, 25 times higher than the rest of the world. It is also quite common in Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
. This could be due to the South East Asian diet which typically includes consumption of salted vegetables, fish and meat. While NPC is seen primarily in middle-aged persons in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, a high proportion of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
n cases appear in children. The cause of increased risk for NPC in these endemic
Endemic (epidemiology)
In epidemiology, an infection is said to be endemic in a population when that infection is maintained in the population without the need for external inputs. For example, chickenpox is endemic in the UK, but malaria is not...
regions is not entirely clear.
See also
- BaseballBaseballBaseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...
player Babe RuthBabe RuthGeorge Herman Ruth, Jr. , best known as "Babe" Ruth and nicknamed "the Bambino" and "the Sultan of Swat", was an American Major League baseball player from 1914–1935...
died from nasopharyngeal carcinoma in 1948. - Lymphoepithelioma-like carcinomaLymphoepithelioma-like carcinomaLymphoepithelioma-like carcinoma, abbreviated LELC, is a malignant epithelial derived tumour, i.e. a type of carcinoma, and similar to lymphoepithelioma ....
External links
- Nasopharyngeal Cancer Or Sinus Infection
- Cancer Management Handbook: Head and Neck Tumors
- Clinically reviewed nasopharyngeal cancer information for patients from Cancer Research UKCancer Research UKCancer Research UK is a cancer research and awareness charity in the United Kingdom, formed on 4 February 2002 by the merger of The Cancer Research Campaign and the Imperial Cancer Research Fund. Its aim is to reduce the number of deaths from cancer. As the world's largest independent cancer...