Hypopharynx

|| ||  ||﻿ ||  ||  || The abundant lymphatics of the hypopharynx allow for a high incidence of metastasis to the regional lymph nodes which include: the midcervical lymph nodes (most commonly involved); contralateral submaxillary nodes; superior deep, middle, and low jugular; and Rouviere’s (lateral retropharyngeal) lymph nodes at the base of the skull. [2] Distant spread can occur in areas such as the brain, liver, lung, kidneys, and bone. || The American Joint Committee on Cancer (AJCC) grading for Hypopharyngeal tumors is as follows: Gx Grade cannot be assessed G1 Well differentiated G2 Moderately differentiated G3 Poorly differentiated || *Subsites of the hypopharynx are as follows: Dermatitis, mucositis, sore throat, dysphagia, xerostomia, gysgeusia and hoarseness Weight loss Late effect: Late laryngeal chondronecrosis or soft tissue necrosis of the pharyngeal wall occurs in 2% to 4%. Severe laryngeal edema 1-6% Permanent gastrostomy for inability to swallon 2-7 % || Small tumor T1N0 and selected T2N0 have higher cure and local control rate and better prognosis than do larger lesion. Poor prognosis signs are positive surgical margin or tumor persistence in the irradiated volume. Early Stage T1-T2: Radiation alone with or without a planned neck dissection is 90% and 80% respectively After surgical salvage, the local control is 91%-95% Locally advanced T3-T4: Local regional control and survival at 4 years are 61% and 28% respectively || A primary conservative surgical approach or primary radiation therapy is a suitable treatment option for early stage hypopharynx cancer (normal vocal cord mobility and no bone invasion). LOCALLY ADVANCED T3N0-T4N0 Postoperative radiation therapy is preferred to improve the local-regional control. STAGE 3 AND STAGE 4 (LYMPH NODES INVOLVED) Surgery in combination with postoperative radiation therapy results in better local regional control rates. Because distant metastases remain a common reason for treatment failure despite adequate local-regional control of disease, systematic therapy is an important consideration in the management of patients. THREE DIMENSIOAL CONFORMAL RADIATION THERAPY (3DCRT): 50 Gy encompasses large field; 1.8 Gy/day/fraction. Off-cord reduction dose at 45 Gy by blocking the spinal cord Boost field is followed up to 66-70 Gy Opposed lateral photon fields, a low anterior neck photon field, and posterior cervical electron field Wedged fields may be required Treatment plan for the boost portion of treatment for a patient with hypopharyngeal cancer extending into cervical esophagus. IMRT: Dose of primary field: 45 Gy Dose of boost field: 25.2 Gy  Total dose: 70.2 Gy  BEAM ARRANGEMENT FOR 3DCRT Superior: Inferior border of mandible and mastoid process ( include margin of jugulargigastric node and retropharyngeal nodes and the entire jugular lymph nodes) Anterior: In front of the thyroid cartilage Posterior: behind the spinous processes with a margin on all nodal disease ( include the posterior cervical lymph nodes) Up to 45Gy- curved border along middle vertebral bodies of cervical spine ( using split beam technique with 6 MV) Inferior: Below the cricoid cartilage, to encompass the tumor extension of 1.5-2.0 cm Typical lateral photon portals, cone-down fields, and doses for hypopharyngeal cancer. Superior: Matched on skin to inferior border of opposed lateral fields, the spinal cord at the junction of field is blocked in the upper fields. Inferior: With low risk of mediastinal disease-below head of clavicles, with blocking inferior to inferior aspect of clavicles With high risk of mediastinal disease: 5cm below heads of clavicles, with lateral blocking extending inferiorly so that mediastinal portion of field is about 8 cm wide Lateral border: Positioned to exclude lateral 1/3 of clavicle Typical low anterior neck portal Matched on skin to off-cord photon fields PATIENT SETUP: Patient supines with head hyperextended. Immobolize with a thermoplastic head and shoulder mask Shoulders need to be away from the lateral fields by rotating the foot of the treatment table 10 to 20 degrees away from the gantry. IMRT: OAR: Lens, eyes, otpic chiasm, cord, parotids, mandible, optic nerve GTV: Clinical and /or radiographic gross desease CTV1: 0.5-2 cm margin on primary and/or nodal GTV (depending on the presence or absence of anatomic bounderies to microscopic spread) CTV2: Elective neck Individualized planning target volumes are used for the GTV, CTV1 and CTV2 IMRT has shown to reduce the long term toxicity in oropharyngeal cancer by reducing dose to salivary glands, temporal lobes, auditory structures and optic apparatus. IMRT Hypopharynx color wash-isodose distribution ||
 * < Epidemiology: ||< Hypopharynx cancer is not very common. Each year the U.S presents with approximately 2,500 new diagnosed cases. This cancer occurs in the pyriform sinus in more than 65% of cases, and about 20% occur in the postcricoid. The last 10-15% occurs from the posterior pharyngeal wall. This is more common in males than females at a ratio of 3:1. There has been an increase in incidence in African Americans since the early 1970’s. The incidence rises in people over 40 years of age and is rare in people under the age of 30. The mean age of when it is presented is 65 years. The typical age range and sex of hypopharyngeal cancer is men between 55-70 years. Hypopharynx cancer is extremely rare in children.
 * < Etiology: ||< The risk factors for upper Hypopharynx cancer include smoking or chewing tobacco, and extensive alcohol use. Lower Hypopharynx cancer is more related to lack of nutrients in diet and presence of Plummer-Vinson syndrome.
 * < Signs & Symptoms: ||< Some signs and symptoms are having a lump in the neck, difficulty and/or pain with swallowing, voice changes (hoarseness), dysphagia, otalgia (ear pain), hemoptysis and halitosis (bad breath).
 * < Diagnostic Procedures: ||< The procedures to diagnose hypopharyngeal cancer are a physical exam where the doctors check the lymph nodes and look down the throat. Another procedure would be an endoscopy where a tube is put in through the nose or mouth to check for anything out of the ordinary. The patient may have a CT and or an MRI. Another procedure would be an esophagoscopy where the doctor looks down the throat into the esophagus. The patient may also have a bronchoscopy which is a procedure that they check the trachea and lung airways. The last procedure for diagnosis would be a biopsy where they take a tissue sample to check for cancerous cells.
 * < Histology: ||< Roughly 95% of hypopharyngeal cancers are squamous cell carcinomas. Of the 95%, 60% are keratinizing and 33% are non-keratinizing and all are usually poorly differentiated. The other more common types would include basaloid squamous cell carcinoma, superficial spreading cancer, sebaceous cancer, and adenosquamous cancer. The epidermal growth factor receptor is over expressed in almost 100% in head and neck cancers.
 * < Lymph Node Drainage: ||< A rich lymphatic network drains the hypopharynx. The lymph nodes which predominantly involves are jugulodigastric, midjugular and parapharyngeal lymph nodes
 * < Metastatic Spread: ||< Common sites of direction invasion are: aryepiglottic folds, false vocal folds, larynx, thyroid cartilage, cricoid cartilage, posterior cricoid muscle, constrictor muscle to the base of the skull, esophagus, and neurovascular spread via the vagus, glossopharyngeal, and sympathetic nerves. [1]
 * < Grading: ||< Tumor grade is a system used to classify cancer cells in terms of how abnormal they look under a microscope in comparison to normal cells of the same tissue type. Cells are classified based on their level of differentiation; which refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated (poorly differentiated) tumor cells which lack the structure of normal cells and grow uncontrollably. [3]
 * < Staging: ||< The American Joint Committee on Cancer (AJCC) TNM system:
 * // Primary tumor (T) //**
 * TX: Primary tumor cannot be assessed
 * T0: No evidence of primary tumor
 * Tis: Carcinoma //in situ//
 * T1: Tumor limited to 1 subsite* of the hypopharynx and 2 cm or less in greatest dimension
 * T2: Tumor invades more than 1 subsite* of the hypopharynx or an adjacent site, or measures more than 2 cm but not more than 4 cm in greatest diameter without fixation of hemilarynx
 * T3: Tumor measures more than 4 cm in greatest dimension or with fixation of hemilarynx
 * T4a: Tumor invades thyroid/cricoid cartilage, hyoid bone, thyroid gland, esophagus, or central compartment soft tissue (including prelaryngeal strap muscles and subcutaneous fat)
 * T4b: Tumor invades prevertebral fascia, encases carotid artery, or involves mediastinal structures
 * Pharyngoesophageal junction (postcricoid area), extending from the level of the arytenoid cartilages and connecting folds to the inferior border of the cricoid cartilage.
 * Pyriform sinus, extending from the pharyngoepiglottic fold to the upper end of the esophagus, bounded laterally by the thyroid cartilage and medially by the surface of the aryepiglottic fold and the arytenoid and cricoid cartilages.
 * Posterior pharyngeal wall, extending from the level of the floor of the vallecula to the level of the cricoarytenoid joints. [4]
 * // Regional lymph nodes (N) //**
 * NX: Regional lymph nodes cannot be assessed
 * N0: No regional lymph node metastasis
 * N1: Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension
 * N2: Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension, or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension, or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
 * N2a: Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension
 * N2b: Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension
 * N2c: Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
 * N3: Metastasis in a lymph node more than 6 cm in greatest dimension [4]
 * // Distant metastasis (M) //**
 * MX: Distant metastasis cannot be assessed
 * M0: No distant metastasis
 * M1: Distant metastasis [4]
 * Stage grouping **
 * // Stage 0 //**
 * Tis, N0, M0
 * // Stage I //**
 * T1, N0, M0
 * // Stage II //**
 * T2, N0, M0
 * // Stage III //**
 * T3, N0, M0
 * T1, N1, M0
 * T2, N1, M0
 * T3, N1, M0
 * // Stage IVA //**
 * T4a, N0, M0
 * T4a, N1, M0
 * T1, N2, M0
 * T2, N2, M0
 * T3, N2, M0
 * T4a, N2, M0
 * // Stage IVB //**
 * T4b, any N, M0
 * Any T, N3, M0
 * // Stage IVC //**
 * Any T, any N, M1 [4] ||
 * < Radiation Side Effects: ||< Acute effects:
 * < Prognosis: ||< Survival progressively declines with increasing age, and women have a significantly higher survival rate after therapy.
 * < Treatments: ||< EARLY STAGE T1N0-T2N0 DISEASE
 * TECHNICAL ASPECTS OF RADIATION THERAPY **
 * DOSAGE: **
 * Opposed lateral photon field **
 * Low anterior neck field: **
 * Posterior electron strips: **
 * < **TD5/5:** ||<  ||<   ||<   ||<   ||<   ||<   ||
 * <  ||< TD 5/5 NORMAL TISSUE TOLERANCE (Gy) ||||||||||<   ||
 * < Organ ||> 1///3// ||< 2/3 ||< 3/3 ||< End point ||
 * < Spinal Cord ||< 50  ||<  50  ||<  47  ||< Myelitis/Necrosis ||
 * < Parotid ||< 32  ||<  32  ||<  32  ||< Xerostomia ||
 * < Mandible ||< 70  ||<  70  ||<  70  ||< Limitation of joint function ||
 * < Lens ||< 10  ||<  10  ||<  10  ||< Cataract ||
 * < Optic chiasm ||< 50  ||<  50  ||<  50  ||< Blindness ||
 * < Optic nerve ||< 50  ||<  50  ||<  50  ||< Blindness ||
 * < Brain stem ||> 54 ||< 54 ||< 54 ||<  ||

= 1. Website Article, Hypopharyngeal Cancer: found at []. Accessed 5-17-2011. = = 2. Website Article, Hypopharyngeal Cancer: found at []. Accessed 5-17-2001. = = 3. Website Article, Hypopharyngeal Cancer: found at []. Accessed 5-18-2011 = = 4. Chao C, Perez C, Brandy L. Radiation Oncology Management Decisions. 2nd ed. Lippincott Williams & Wilkins, Philadelphia, PA. 2002:255-263. = 1. Steven AL, Theodore LP. Textbook of Radiation Oncology, 2nd ed. Saunders; 2004.

2. Eric KH, Mack R. Handbook of Evidence-Based Radiation Oncology; 2nd ed. Springer; 2010.

3. Anne Marie V, Byron GD, Sharon KC, Nancy HW. Portal Design in Radiation Therapy; 2nd ed. R.L Bryan Company; 2006.

[1] Chao C, Perez C, Brady L. Hypopharynx. //Radiation Oncology.// //2nd ed//. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:255-257.

[2] Washington C, Leaver D. Head and Neck Cancers. //Principles and Practice of Radiation Therapy. 2nd ed.// St. Louis, MO: Mosby; 2004:706.

[3] National Cancer Institute. // Tumor Grade: Questions and Answers //. Available at: []. Accessed May 24, 2011.

[4] DoctorsLounge.com. // Staging of hypopharyngeal cancer //. Available at: [] __. __ Accessed May 25, 2011.