------------------------------------------------------------------------------- TITLE: NECK DISSECTION: TREATMENT OF THE N0, N1, N2, AND N3 NECK SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: January 24, 1996 RESIDENT PHYSICIAN: Christopher P Thompson, M.D. FACULTY: Christopher Rassekh, M.D. SERIES EDITOR: Francis B. Quinn, Jr., M.D. ------------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." I. HISTORY A. 1906 - The en bloc cervical lymphadenectomy known as the radical neck dissection was developed by Crile 1. spinal accessory and hypoglossal were preserved 2. internal jugular vein removed B. Blair and Brown encourage the removal of the spinal accessory nerve C. 1950 - Martin popularizes the radical neck dissection explaining that "any technique that is designed to preserve the spinal accessory nerve should be condemned unequivocally." D. 1945 - Dargent and Papillon advocate the preservation of the spinal accessory nerve in clinically N0 necks E. 1969 - 1981 Roy and Beahrs, Carenfelt and Eliasson propose the preservation of CNXI in clinically positive necks F. 1963 - Suarez indicates that based on his necropsy specimens which had lymphatics only within the fibrofatty tissues, a complete cervical lymphadenectomy could be accomplished while sparing the sternocleidomastoid muscle, the internal jugular vein, and the spinal accessory nerve G. 1967 - 1980 Bocca and Pignataro popularize Suarez's version of neck dissection and coin the terms functional, conservative, and conservation neck dissection H. 1972 Lindberg's classic study indicates consistent patterns of lymphatic drainage for carcinomas in various locations of the upper aerodigestive tract I. 1990 - Shah's work confirms that of Lindberg's in a review of over 1000 neck dissection specimens J. 1986 - 1991 Byers, Medina, and Spiro report their results with selective neck dissection II. LYMPHATIC ANATOMY A. The division of the neck nodes into regions as described at Memorial Sloan-Kettering is accepted universally 1. Level 1 contains the submental and submandibular nodes 2. Level 2 is the upper third of the jugular nodes medial to the SCM and has as its inferior boundary the plane of the hyoid bone (clinical) or the bifurcation of the carotid artery (surgical) 3. Level 3 describes the middle jugular nodes and is bounded inferiorly by the plane of the cricoid cartilage (clinical) or the omohyoid (surgical) 4. Level 4 is defined superiorly by the omohyoid muscle and inferiorly by the clavicle 5. Level 5 contains the posterior cervical triangle nodes 6. Level 6 are the paratracheal and pretracheal nodes III. CERVICAL METASTASIS A. Incidence - the propensity for squamous cell carcinomas to metastasize depends on its size and on its location in the upper aerodigestive tract 1. Larger tumors have a greater likelihood of cervical spread 2. Pharyngeal lesions tend to metastasize more frequently than those in the oral cavity or larynx B. Detection 1. Most large studies agree that the sensitivity and specificity of clinical examination in the detection of cervical metastasis are in the 40 - 60% range i. Sensitivity in level 3 seems to be higher than in levels 1 and 2 according to the recent study by Kowalski ii. Body habitus influences the ability to detect metastasis iii. Preoperative radiation therapy decreases the sensitivity of neck palpation according to some authors 2. MRI and CT scanning has demonstrated greater sensitivity in the detection of nodes larger than 1 to 1.5 cm i. Unfortunately, lymph node size does not always correlate with metastatic disease ii. Recent work by Don demonstrated that 67% of malignant lymph nodes were 1cm or less in diameter which would correspond to a sensitivity of 33% if this size were used as the cutoff iii. Central lucency was once considered pathognomonic of necrotic tumor, whereas recent reports describe similar findings with fatty inclusions within nodes as well as in small arteries with intralumenal plaques iv. Other criteria such as morphology, and grouping of nodes may enhance detection, but definitive studies are required v. This recent evidence calls into question the necessity of routine neck scanning in all head and neck cancer patients B. Prognostic implications 1. Overall, cervical metastasis is the single most important prognosticator in head and neck squamous cell carcinoma, and its presence indicates roughly a 50% reduction in overall survival a. The presence of extracapsular spread (ECS) carries a particularly poor prognosis i. as indicated in the study by Johnson, only 40% of patients had a 24 month period of disease free survival ii. macroscopic ECS has been said to carry a worse prognosis than microscopic ECS but definitive studies are pending b. The level of nodal involvement has prognostic implications with survival decreasing in those patients with involvement beyond the first echelon of lymphatic drainage; very low survival is indicated by level V involvement in non-nasopharyngeal tumors c. The number of involved nodes significantly impacts on survival with involvement of two or more nodes carrying a much higher incidence of distant metastasis C. Location of spread 1. The work of Lindberg, Shah, and Byers indicate that the lymphatic drainage of the upper aerodigestive tract occurs along predictable pathways a. These studies only apply to untreated necks b. Oral cavity tumors metastasize to regions I - III c. Lesions of the oropharynx, larynx, and hypopharynx spread to regions II - IV d. Tonsillar, posterior pharyngeal wall, and possible base of tongue lesions have a propensity for level V metastasis 2. These studies examined both N0 and N+ necks 3. Also demonstrated in these studies was retropharyngeal node involvement in as many as one-third of lesions of the hypopharynx and paratracheal node metastases with subglottic lesions D. Treatment 1. Three treatment options exist a. Expectant management i. In the N0 neck, no prospective studies demonstrate survival differences between surgical, radiation, and expectant management ii. However, the prognosis for the development of subsequent cervical metastasis is poor and most clinicians agree that if the primary lesion poses more than a 20% likelihood of metastasis, either surgery or radiation therapy is beneficial at the time of primary treatment b. Radiation therapy i. It is accepted that radiation therapy in the N0 neck will reduce the conversion rate of that neck to about 5% ii. The N+ neck is more effectively treated with a combination of surgery and radiation c. Surgery i. With the development of less morbid neck dissections, surgical treatment of the N0 neck can provide significant prognostic information and likely therapeutic benefits with a minimum of shoulder dysfunction ii. The surgical choices in the N1 neck remain controversial as a balance between morbidity and completeness of resection is sought; ideally, either surgery or radiotherpy rather than the combination is desirable iii. The therapy of the N2/N3 neck is most effectively treated with a combination of surgery (utilizing a comprehensive neck dissection) and radiotherapy IV. CLASSIFICATION OF NECK DISSECTION A. Comprehensive neck dissections - includes the radical neck dissection and three modifications, but always refers to a procedure in which all of groups I - V are removed 1. Radical neck dissection a. Involves the removal of all lymphatics from the inferior border of the mandible to the clavicle between the lateral border of the strap muscles and the anterior border of the trapezius b. The deep margin of resection is the fascial carpet of the scalene muscles and the levator scapulae c. The SCM, the internal jugular vein, and the spinal accessory nerve are removed with the specimen d. Traditionally, the only surgical method of treating the neck i. But with the development of the more limited, less morbid modifications this is no longer indicated in the N0 neck ii. Many surgeons no longer advocate this approach in N+ necks unless the metastatic nodes involve the muscle, vein, or nerve 2. Modified Radical Neck Dissection a. Based on the work of Suarez as well as that of Bocca and Pignataro i. Indicate that an en bloc removal of the cervical lymphatics can be accomplished by stripping the fascia from the SCM and internal jugular vein ii. No lymphatic communication was ever noted between these structures and the cervical lymphatics iii. These studies point out that both the spinal accessory and the hypoglossal nerve do not follow the aponeurotic compartments, but rather run across them; however, their conclusion was that if the tumor did not directly involve the nerves, they could be spared b. From the above information and a desire to minimize the shoulder dysfunction associated with spinal accessory nerve sacrifice came the development of the modified radical neck dissection 3. Type I Modified Radical Neck Dissection a. Accomplishes the removal of the same regions of lymphatics as in the radical neck dissection, but the spinal accessory nerve is spared b. Used less commonly in the N0 neck, but would be a reasonable choice with neck disease that involved the SCM or jugular vein without involving the spinal accessory nerve c. In a recent study by Anderson, radical neck dissection was compared to Type I modified radical neck dissection i. neither survival nor tumor control in the neck was affected by preservation of the spinal accessory nerve ii. the pattern of failure was the same for the two different procedures; the nerve preservation did not predispose to recurrence in that area 4. Type II Modified Radical Neck dissection a. Involves the same dissection as in the radical neck, but the spinal accessory nerve and internal jugular vein are spared b. Similarly indicated in N+ necks with metastatic involvement of the SCM, but without involvement of the nerve and vein 5. Type III Modified Radical Neck dissection - aka "functional neck dissection" a. Similar dissection to the radical neck with preservation of all three structures b. The indications for this procedure are controversial i. In Europe, this operation is popular in the treatment of hypopharyngeal and laryngeal tumors with N0 necks ii. Molinari, Lingeman, and Gavilan propose this procedure for N1 necks when the involved nodes are mobile and no greater than 2.5 to 3cm ii. Bocca proposes this operation for any neck that has indications for a radical neck dissection as long as the nodes are not fixed c. The results from Byer's study demonstrate recurrence rates similar to those associated with radical neck dissection B. Selective Neck Dissections 1. This type of dissection arose from the work of Shah, Lindberg, and Byers which identified the pathways of lymphatic spread in the head and neck a. Only those regions with high risk for metastasis are removed b. A subject of great controversy, some surgeons feel that in necks with limited disease, these procedures provide the same therapeutic value i. Recent work by Byers indicates that patients undergoing selective neck dissection with N1 disease and a mobile node less than 3cm in the first echelon of lymphatic drainage have similar recurrence rates to those having a radical neck dissection ii. Another recent investigation by Kowalski recommends selective neck dissection for oral cavity cancers with positive nodes at level 1 c. This type of dissection provides the same staging information that radical neck dissection does, so that prognosis and the necessity of radiation therapy can be assessed d. Manipulation of the spinal accessory nerve is minimized in selective neck dissections i. Although there is short-term shoulder morbidity with selective neck dissection, Sobol's prospective study indicates that by 16 weeks, patients performed significantly better than those who had radical neck dissection ii. This same study compared supraomohyoid neck dissection to modified radical and found that the limited dissection allowed a quicker return to normal function, but at one year the difference became less 2. Types of selective neck dissection a. Supraomohyoid (anterolateral) neck dissection i. Levels I, II, and III are removed sparing the SCM, IJ, and CNIX ii. Indicated in the treatment of oral cavity lesions b. Lateral neck dissection i. Levels II. III, and IV are removed sparing the SCM, IJ, and CNIX ii. Indicated in tumors of the larynx, oropharynx, and hypopharynx when the neck is N0, although some advocate this approach with the N1 neck with nodes limited to level II c. Posterolateral neck dissection i. Levels II, III, IV, and V are removed sparing the SCM, IJ, and CNIX ii. Useful in the treatment of skin tumors with metastatic potential located in the posterior scalp or neck such as melanomas, squamous cell carcinomas, and Merkel cell carcinomas C. Extended neck dissections - describes any of the above dissections that include the removal of additional structures or other groups of lymph nodes 1. Retropharyngeal node involvement often occurs in tumors of the pharyngeal walls, and would warrant an extended neck dissection 2. Thyroid, subglottic, tracheal and cervical esophageal carcinomas require the extension of the neck dissection to include level VI 3. Tumor extension involving the carotid artery, the hypoglossal nerve, the levator scapulae muscle may necessitate excision of these additional structures V. CONCLUSION A. Metastatic cervical disease has a tremendous impact on prognosis in patients with carcinomas of the head and neck, and the incidence of such spread is greater than 20% for the vast majority of squamous cell carcinomas B. Detection of such metastasis is currently less than ideal 1. Clinical exam provides on the order of 50% sensitivity and the addition of CT scanning adds significantly to the detection of nodes larger than 1 to 1.5cm; however, the correlation of size and presence of metastatic disease remains controversial 2. Research with multidirectional ultrasonography in combination with fine-needle aspiration seems promising 3. Contrast agents such as iron oxide during MRI scan have provided encouraging results showing reduced signal intensity in normal nodes after contrast administration C. The treatment of the N0 neck now focuses on minimizing morbidity so that in lesions with a high likelihood of metastasis (>20%), a selective neck dissection significantly limits shoulder dysfunction, improves cosmesis, yet provides valuable therapeutic and prognostic benefits D. The N1 neck is controversial as some surgeons recommend selective neck dissection in necks with very limited disease; traditional thinking utilizes comprehensive neck dissection ---------------------------------------------------------------------------- BIBLIOGRAPHY Andersen P, Shah J. The role of comprehensive neck dissection with preservation of the spinal accessory nerve in the clinical positive neck. Am J. Surg 1994;168:499. Bailey B. Head and Neck Surgery - Otolaryngology. J.B. Lippincott Co, Philadelphia, 1993. p 1192 - 1220. Don D. Evaluation of cervical lymph node metastases in squamous cell carcinoma of the head and neck. Laryngoscope 1995;105:669. Houck J, Medina J. Management of cervical lymph nodes in squamous carcinomas of the head and neck. Seminars in Surgical Oncology 1995;11:228. Henick D. Supraomohyoid neck dissection as a staging procedure for squamous cell carcinomas of the oral cavity and oropharynx. Head and Neck 1995;17:119. Johnson J. Carcinoma of the larynx: Selective approach to the management of cervical lymphatics. ENT Journal 1994;73(4):303. Kligerman J. Supraomohyoid neck dissection in the treatment of T1/T2 squamous cell carcinoma of the oral cavity. Am J Surg 1994;168:391. Kowalski L. Supraomohyoid neck dissection in the treatment of head and neck tumors. Arch Otolaryngol Head Neck Surg 1993;119:958. Mcguirt W. Floor of mouth carcinoma. Arch Otolaryngol Head Neck Surg 1995;121:278. Ramadan H. The influence of elective neck dissection on neck relapse in N0 supraglottic carcinoma. Am J Otolaryngology 1993;14(4):278. Sobol, S. Objective comparison of physical dysfunction after neck dissection. Am J. Surg 1985;150:503. Spiro R. Selective jugular node dissection in patients with squamous carcinoma of the larynx or pharynx. Am J Surg 1993;166:399. Spiro R. Classification of neck dissection: variations on a new theme. Am J Surg 1994;168:415. Weiss M. Use of decision analysis planning a management strategy for the stage N0 neck. Arch Otolaryngol Head Neck Surg 1994;120:699. ----------------------------END-----------------------------------------