Nasopharynx

Faleesa Austin, Nick, Jake Osen, Dustin, Holly Hardin, Eyob , Bret
 * **Epidemiolgy:** || Incidence rate is high in southern Chinese and middle Eastern countries due to the nitosamines located in salted fish eaten. 1 Incidence rate is also high for Eskimos and people of Southeast Asia. A small increase incidence happens in young adulthood and increases between the years of age 50-70. Incidence in white populations is uncommon. ||
 * **Etiology:** || Tobacco smoke is not related to the development of nasopharynx cancer (NPC). 1 Exposure to occupational hazards such as wood dust, leather tanning chemicals, and chemicals used in textile steel industries is known to increase the incidence rate of NPC. The Epstein-Barr (EBV) is linked to the development of NPC. ||
 * **Signs & Symptoms:** || While not all of these signs and symptoms guarantee a cancer diagnosis, they have shown to be related to NPC. 2


 * Trouble breathing
 * Issues with speaking
 * Decline of hearing
 * A lump in the nose/neck
 * Otitis media
 * Sore throat
 * Epistaxis
 * Tinnitus
 * Headaches ||
 * **Diagnostic Procedures:** || There are a variety of diagnostic procedures that can be used to help detect the presence of a NPC. 2

Reprinted from American Cancer Society, 2013. 3


 * Physical exam: Physician will feel for potentially swollen nodes in the cheeks and neck.
 * Nasoscopy: Using a tube shaped camera they are able to see and evaluate any suspicious looking tissue.
 * Neurological Exam: A variety of questions can be used to check the brain, spinal cord, and nerve functions.
 * Magnetic Resonance Imaging (MRI): Imaging using a magnet and radio waves to create an image that better visualizes soft tissue.
 * Computed Tomography (CT) Scan: A three dimensional scan that uses x-rays and digital imaging to visualize patient anatomy.

Reprinted from About Cancer, 2013. 4


 * Positron Emission Tomography (PET) Scan: A scan that detects the regions of glucose uptake, typically due to tumor existence.

Reprinted from About Cancer, 2013. 5   GX: Grade cannot be assessed G1: Well differentiated G2: Moderately differentiated G3: Poorly differentiated G4: Undifferentiated || NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis N1 Unilateral metastasis in lymph node(s), <6cm in greatest dimension, above the supraclavicular fossa N2 Bilateral metastasis in lymph node(s), <6cm in greatest dimension, above the supraclavicular fossa N3 Metastasis in a lymph node(s) N3a >6cm in greatest dimension N3b Extension to the supraclavicular fossa || Stage 1 - In this stage, 70 out of every 100 people (70%) will live for at least 5 years. Stage 2 - 65% of all people diagnosed with stage 2 NPC will live for at least 5 years. Stage 3 - Of all those people diagnosed with stage 3 NPC, about 60 out of every 100 people (60%) will live for at least 5 years. Stage 4 - Of all the people diagnosed with stage 4 nasopharyngeal cancer, around 40 out of every 100 people (40%) will live for at least 5 years. ||
 * Lab Tests: Complete blood count (CBC), and urinalysis can help with diagnosis and monitoring the patient. Also, an Epstein-Barr virus titer can be foretelling.
 * Biopsy: Removing a section will help the pathologist determine the type of tumor. ||
 * **Histology:** || The epithelium of the nasopharynx is very similar to respiratory type epithelium with ciliated pseudostratified columnar goblet cells near the nasal cavity and non-keratinising stratified squamous cells near the pharyngeal isthmus. 7 There are also numerous submucosal and mucosal glands that open onto the mucosal surface. ||
 * **Lymph node drainage:** || 75% to 85% of nasopharynx patients have cervical nodes that are clinically positive for disease, and about half of all cases have bilateral or contralateral disease. 6 Fields usually encompass all nodes at risk including lateral retropharyngeal, node of Rouviere, and jugulodigastric nodes. Retropharyngeal nodes are usually the first path of drainage, followed by deep cervical nodes, and lateral mastoid or spinal accessory nodes. 7 ||
 * **Metastatic spread:** || NPC has a 30-40% local recurrence rate. Metastatic is through the blood and lymphatic system. Bilateral cervical nodes have up to 40-70% chance of developing distant metastasis to common sites (bone, lung, and liver). 8 ||
 * **Grading:** || Histologic grade (G): 3
 * **Staging:** || Staging: 1
 * **Radiation side effects:** || Side effects and management: 1
 * Extraction of carious teeth should be done prior to RT, extraction after can lead to osteoradionecrosis
 * Mucositis (after 2000 to 3000 cGy) can lead to weight loss. Placement and use of a feeding tube can help with this problem.
 * Xerostomia (after 1000 to 2000 cGy) (may be permanent after 4000 cGy). Salagen can help stimulate saliva production. Saliva substitutes are used to decrease sensation of dry mouth
 * Cataracts of the lens of the eye can occur around 1000 cGy (can be removed surgically)
 * Taste Changes occur as taste buds are affected around 1000 cGy (may last several weeks post-radiation or be permanent)
 * Skin reactions- Erythema-skin redness. Dry desquamation - treated with moisturizing lotion/gel. Hydrocortizone cream can be used on dry, inflammed skin but do not use for moist desquamation. ||
 * **Prognosis:** || Staging: 9
 * **Treatments:** || Radiation therapy is the primary treatment for NPC. 9 Radiation therapy may be given alone or with chemotherapy. Surgery is not often used to treat NPC because the area is so difficult to reach.

Patients with early disease have a good chance of survival. Radiation toxicities in critical structures would affect the quality of life of survivors. There are challenge in achieving adequate tumor controlling dose to the primary tumor with sparing the critical organs in patients with advanced disease. Major limitations of conventional two dimensional (2D) radiotherapy for nasopharyngeal cancer can now be overcome with three dimensional (3D) conformal radiation therapy and intensity-modulated radiotherapy (IMRT). 10

Reprinted from Japanese Journal of Clinical Oncology, 2013. 11

Isodose curves of a multi-segmental IMRT using seven coplanar gantry angles delivered for a patient with T2bN0M0 carcinoma of the nasopharynx displayed on the axial (a), coronal (b) and sagittal (c) planes and the dose-volume histogram (DVH) for critical structures (d). 11 || Spinal Cord- 4500 cGy Optic Nerve- 5000 cGy Pituitary Gland- 4500 cGy Brainstem- 5000 cGy Ear- 5000 cGy Lens- 500 cGy || Reprinted from Radiation Oncology Management Decisions, 2013. 13   The above image shows IMRT target delineation for a patient with T2N1 NPC. The planning CT scans are in axial views at four anatomical levels. The contours include: Gross tumor volume (GTV); clinical target volume (CTV); CTV1, high-risk volume; CTV2, intermediate-risk volume (outer contour outside of red GTV); CTV3, low-risk volume. 13 ||
 * **TD 5/5:** || The normal structures that must be considered when treating the nasopharynx include the spinal cord, optic nerve, pituitary, brainstem, ear, and lens of the eye. The TD 5/5 for the whole organs are: 12
 * **Images** || [[image:figure_14-4.jpg width="560" height="496"]]
 * **References:** || # Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby Elsevier; 2010: 726-727.
 * 1) Nasopharyngeal cancer treatment. National Cancer Institute. 2012. Available at: [|http://www.cancer.gov/cancertopics/pdq/treatment/nasopharyngeal/HealthProfessional#Section_132]. Accessed May 30, 2013.
 * 2) What is nasopharyngeal cancer? American Cancer Society Web site. http://www.cancer.org/cancer/nasopharyngealcancer/detailedguide/nasopharyngeal-cancer-what-is-nasopharyngeal-cancer. Accessed June 2, 2013.
 * 3) PET and CT scans of PET and CT Scans of specific cancers. About Cancer Web site.http://www.aboutcancer.com/nasopharynx_ct_sah_0409.jpg. Accessed June 2, 2013.
 * 4) PET and CT scans of PET and CT Scans of specific cancers. About Cancer Web site.http://www.aboutcancer.com/nasopharynx_pet_bmc_1207.jpg. Accessed June 2, 2013.
 * 5) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby-Elsevier;2010.
 * 6) Nasopharynx. OzRadOnc Web site. http://ozradonc.wikidot.com/anatomy:focused-nasopharynx. 2011. Accessed May 29, 2013.
 * 7) NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers. National Comprehensive Cancer Network Web site. http://www.nccn.org/professionals/physician_gls/pdf/head-and-neck.pdf. Accessed May 28, 2013.
 * 8) Cancer Research UK. About nasopharyngeal cancer. Available at http://www.cancerresearchuk.org/cancer-help/type/nasopharyngeal-cancer/about. Accessed May30, 2013
 * 9) Yoshizaki T, Ito M, Murono S, Wakisaka N, Kondo S, Endo K. Current understanding and management of nasopharyngeal carcinoma. // Auris, Nasus, Larynx // . 2012;39(2):137-144. doi:10.1016/j.anl.2011.02.012.
 * 10) Liu M, Hsieh C, Chang T, Lin J, Huang C, Wang A. Prognostic Factors Affecting the Outcome of Nasopharyngeal Carcinoma. Jpn. J. Clin. Oncol. 2003;33(10):501-508. doi:10.1093/jjco/hyg092.
 * 11) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby-Elsevier; 2010.
 * 12) Chao K, Perez CA, Brady LW. // Radiation Oncology Management Decisions // . 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002. ||

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