User:Tnnassar/Nasopharyngeal carcinoma

Treatment
Generally, there are three different types or treatment methods that can be used for patients with nasopharyngeal carcinoma. These three treatments are radiation therapy, chemotherapy, and surgery. Although there are currently three treatment methods, there are clinical trials taking place that may develop more effective treatments for NPC. A clinical trial is research study that works to develop new treatment techniques or to gain more information about or improve current methods. If an effective treatment comes out of the clinical trial, then this method may become a new standard treatment method. During the course of, or following, treatment, tests may be done in order to determine if the treatment is working, or if treatment needs to be dropped or changed. Tests that are done after treatment to determine the condition of patient after completing treatment are called follow-up tests and tell the doctor if the patients condition has changed or if the cancer has come back.

Radiation therapy
Radiation therapy uses high energy x-rays or other types of radiation aimed to prevent cancer cells from growing or kill them altogether. This kind of therapy can be administered to the patient externally or internally. With external radiation, a machine is used to send targeted radiation to the cancer site. A mesh mask is used on the patenting order to keep their head and neck still while the machine rotates to send out beams of radiation. In undergoing this kind of treatment, healthy cells may also be damaged during the process. Therefore, there are 2 other forms of radiation therapy that decreases the likelihood of damaging nearby healthy cells: intensity-modulated radiation therapy and stereotactic radiation therapy. Intensity-modulated radiation therapy (IMRT) uses 3D images of the size and shape fo the tumor to then direct thin beams of radiation at different intensities from multiple angles. In stereotactic radiation therapy, radiation is aimed directly at the tumor. in this therapy, the total amount of radiation is divided into smaller does that will be given over the course of several days.

Using radiation therapy as a cancer treatment method depends on the type and stage of cancer, however, internal and external radiation therapies can be used to treat NPC. If external radiation therapies are being aimed at the thyroid, then this could effect the way the thyroid works. For that reason, blood tests are done before and after radiation to check thyroid hormone levels.

Chemotherapy
Chemotherapy works as cancer treatment by using drugs that stop the growth of cancer cells, by either killing the cells or preventing them from dividing. This kind of therapy can be administered systemically or regionally. Systemic chemotherapy is when the chemotherapy is taken orally or is injected into a vein or muscle. In this method, the drug circulates through the blood system and can reach cancer cells throughout the body. Regional chemotherapy is when chemotherapy is administered directly into the cerebrospinal fluid, an organ, or a body cavity, for example, the abdomen. In this way, the drugs will mainly affect cancer cells in that area. However, the type of chemotherapy that is administered to the patient depends on the type and stage of the cancer. Additionally, chemotherapy can be used as an adjuvant therapy after radiation to lower the risk of recurrence in the patient. If given after radiation, chemotherapy can be used to kill any cancer cells that may have remained.

Surgery
Surgery can be used as a method to determine whether there is cancer present or to remove cancer from the body. If the tumor does not respond to radiation therapy, then the patient may undergo an operation to have it removed. Cancers that may have spread to the lymph nodes may require the doctor to remove lymph node or other tissue in the neck.

Risk factors
Nasopharyngeal carcinoma, classified was a squamous cell cancer, has not been linked to excessive use of tobacco. However there are certain risk factors that can predispose an individual to NPC if exposed to them. These risk factors include: having Chinese, or Asian, ancestry, exposure to Epstein- Barr virus (EBV), unknown factors that result in rare familial clusters, and heavy alcohol consumption.

EBV
Epstein- Barr virus infects and persists in more than 90% of world population. Transmission of this virus occurs through saliva and is more commonly seen in developing countries where there are living areas are more packed together and less hygienic. Replication of this virus can occur in the oropharyngeal epithelial tissue and nasopharyngeal tissue. EBV primarily targets B lymphocytes. Patients diagnosed with NPC were found to shown elevated levels of the antibodies against the EBV antigen than in individuals not diagnosed with NPC.

Smoking
Individuals that are exposed to cigarette smoking have an increased risk of developing NPC by 2- to 6-fold. Approximately two-thirds of patients with type 1 NPC was attributed to smoking in the United States. However the declining rates of smoking in the US can be associated with less prevalence of type 1 NPC. In southern China and North Africa, it has been suggested that high smoking rates come from wood fires in the country rather than cigarette smoking.

Signs and Symptoms
NPC may present as a lump or a mass on both sides towards the back of the neck. These lumps usually are not tender or panful but appear as a result of the metastatic spread of the cancer to the lymph nodes, thus causing the lymph nodes to swell. Lymph nodes are defined as glands that function as part of the immune system and can be found throughout the body. Signs of nasopharyngeal cancer may appear as headaches, a sore throat, and trouble hearing, breathing, or speaking. Additional symptoms of NPC include facial pain or numbness, blurred or double vision, trouble opening the mouth, or recurring ear infections. If the ear infection does not present with an upper respiratory tract infection, then an examination should be done on the nasopharynx. This is due to the fact that, in adults, ear infections are less common than in children.

Classification
The World Health Organization (WHO) has identified three subtypes of nasopharyngeal carcinoma:


 * type 1: squamous cell carcinoma, typically found in older adults
 * type 2: non-keratinizing carcinoma
 * type 3: undifferentiated carcinoma

Type 3 is most commonly found among younger children and adolescents, with a few type 2 cases. Both type 2 and 3 have been found to be associated with elevated levels of Epstein-Barr virus titers, but not type 1. Additionally, type 2 and type 3 may be followed with an influx of inflammatory cells, including lymphocytes, plasma cells, and eosinophils, generating the term lymphoepithelioma.