Early Laryngeal Cancer
Parul Sinha
Oluwafunmilola Okuyemi
Bruce H. Haughey
The term “early laryngeal cancer” refers to a mucosally derived neoplastic lesion that may invade deeply into soft tissue, but not into the underlying cartilage. The majority of literature reports include carcinoma in situ (CIS), T1 and T2 lesions in the spectrum of early laryngeal cancer. At the glottic level, early cancer implies a local lesion limited to single or multiple sites in the glottis or adjacent laryngeal subsites that might impair the cord mobility but does not cause cord fixation. Overall, these lesions display pathologic invasiveness and a potential to metastasize, which exceeds that of CIS but is less than deeply infiltrating carcinoma (1). By contrast, early supraglottic cancer may not be confined to the primary site because of its regional metastatic behavior. Pathologic invasion of the epiglottic cartilaginous foramina, short of entering the preepiglottic space (PES), is included.
EPIDEMIOLOGY
Laryngeal cancer is the second most common type of head and neck cancer worldwide, with an estimated incidence of 151,000 cases resulting in about 82,000 deaths annually (2). With a male-to-female ratio of 6:1, laryngeal cancer is also the 13th most common cancer in men worldwide (2). Geographic variations in the incidence and mortality of laryngeal cancer suggest that a larger proportion of the cases occur in South-Central Asia, Eastern Asia, Central Europe, and Eastern Europe (2): incidence in the United States has declined, associated with reduced smoking (3).
In the United States, laryngeal cancer accounts for about one-fourth of the annual cases of head and neck cancer with an estimated incidence of 12,720 cases (4). Overall, about 60% of laryngeal cancer cases are diagnosed as “early laryngeal cancer” and encompass the Tis, T1N0M0, or T2N0M0 categories (5). These commonly arise from the glottis and are mostly squamous cell carcinoma (6). Variation in site predominance, however, has been reported across ethnic groups; for example, glottic cancers appear to be the most common in Caucasians, while in African Americans, the incidence of glottic and supraglottic cancers appear to be equal (7).
RISK FACTORS
Smoking and alcohol consumption are well-established etiologic factors for laryngeal cancers. Their combined use has been associated with a multiplicative effect for the risk of developing laryngeal cancer (8,9). A recent study by Hashibe et al. (10) showed that the incidence of cancers attributable to tobacco and alcohol exposure was the highest in larynx of all head and neck cancer sites at 89%. About 5% of laryngeal cancers occur in nonsmokers and nondrinkers, suggesting that other factors such as diet, gastroesophageal reflux, previous radiation, and viral infection may also contribute (11). Human papillomavirus types 16 and 18 have been detected in frequencies ranging from 5% to 32% of analyzed samples in laryngeal cancer (11). Occupational exposures to wood dust, polycyclic hydrocarbons, and asbestos have also been associated with increased risk for developing laryngeal cancer (12).
TUMOR BIOLOGY
Genetics
Genetic alterations have been shown to underlie the development of precancerous lesions and their progression to invasive laryngeal carcinoma (13,14,15). Loss of heterozygosity and microsatellite instability at certain genetic loci has been identified in the progression to invasive laryngeal cancer (13).
Mutations in p16, a tumor suppressor gene located at chromosome 9p21, occur in over half of laryngeal squamous cell carcinomas and are believed to occur early in the progression to invasive squamous cell carcinoma (SCC) of the larynx (16).
Overexpression of cyclin D1, a key cell-cycle regulatory protein, results in increased cellular proliferation and tumorigenesis (17). It has also been shown to correlate with poor prognosis, recurrence, and lymph node metastasis (18).
Alterations in p53, a tumor suppressor gene that maps to the 17p13 locus, result in destabilization of genomic repair processes leading to tumorigenesis (17).
Pathology
Laryngeal cancer is thought to arise from precancerous lesions. These precancerous lesions are characterized by atypical cellular changes with malignant features (loss of cell maturation, nuclear atypia, increased mitotic activity) that occur in response to carcinogenic exposures especially tobacco smoke and alcohol. The precancerous lesions include dysplasia (graded from “mild” to “severe” depending on the extent of epithelial involvement) and CIS (involvement of the whole thickness of the epithelium). These preinvasive lesions are, by definition, confined to the epithelium of the larynx with an intact basement membrane. Progression to microinvasive and invasive carcinoma is characterized by infiltration of basement membrane and the underlying tissue.
Histologically, squamous cell carcinomas account for over 95% of primary laryngeal cancers and arise from the stratified squamous epithelium lining the larynx (8). Other lesscommonly encountered histologic types of primary laryngeal cancer include verrucous squamous cell carcinoma (a highly differentiated variant with low incidence for metastases), adenocarcinoma, spindle cell carcinoma, fibrosarcoma, and chondrosarcoma. Neuroendocrine tumors, though rare, are the most common nonsquamous tumors encountered and have a predilection for the supraglottic larynx.
ANATOMY OF THE LARYNX
The laryngeal skeleton is composed of cartilages—thyroid, cricoid, arytenoids, epiglottis, cuneiform, and corniculate— interconnected with ligaments and membranes and moved by groups of intrinsic and extrinsic laryngeal muscles (see Fig. 124.2).
Anatomical subsites: The larynx is divided into three regions: supraglottis, glottis, and subglottis. The supraglottis extends from the epiglottis to the ventricular apices, encompassing the false cords, aryepiglottic folds, the arytenoids, and the laryngeal surface of the epiglottis. The glottis contains the true vocal cords, the anterior commissure, the interarytenoid region, and the floor of the ventricles. It extends inferiorly to 1 cm below the plane of the apex of the ventricles. The true vocal cords thicken at the anterior commissure and form the macula flava, anterior to which the ligaments merge into the Broyle tendon. The Broyle tendon, also known as anterior commissure tendon, gets inserted into the thyroid cartilage. The subglottis extends from 1 cm below the apex of ventricles to the lower border of the cricoid cartilage.
Laryngeal membranes: The conus elasticus or the cricovocal membrane arises from the inner surface of the cricoid arch and extends superiorly to attach anteriorly to the inner surface of the thyroid cartilage and posteriorly to the tip of the vocal process of arytenoids. Its free upper border thickens to form the vocal ligament. The quadrangular membrane extends between the arytenoids and epiglottis. Its upper border forms the aryepiglottic fold, while the free lower border constitutes the false cord. The thyrohyoid membrane is another fibroelastic membrane that attaches inferiorly to the upper border of the thyroid cartilage and superiorly to the posterior surface of hyoid bone.
Laryngeal spaces: Knowledge of laryngeal spaces is important to the understanding of the spread of laryngeal cancer and, therefore, planning of conservation surgical procedures. The preepiglottic space or the space of Boyer lies anterior to the infrahyoid epiglottis. It is bounded superiorly by the hyoepiglottic ligament, inferiorly by the attachment of epiglottis to the thyroid and anteriorly by the thyrohyoid membrane and upper part of the thyroid cartilage. It contains fibrofatty tissue and numerous lymphatic channels. Laterally, it merges with the paraglottic space. The paraglottic space surrounds the laryngeal ventricle and is bounded anterolaterally by the thyroid cartilage, posterolaterally by pyriform sinus mucosa, superomedially by quadrangular membrane, and inferomedially by conus elasticus. The paraglottic space provides an important route to extralaryngeal spread of cancer.
Lymphatic pathways: The supraglottis has a rich lymphatic network. The lymphatics drain primarily to the upper jugular (level II) chain of lymph nodes. It can extend to the middle (level III) and lower jugular groups (level IV), and depending on the site of tumor, cross-drainage may occur to the contralateral nodes. Lymphatic drainage from the glottis is essentially nonexistent although the cords themselves have a network of superficial mucosal lymphatics. The paratracheal (level VI) group of lymph nodes is the primary echelon of lymphatic drainage from the subglottis that may further spread to the delphian node and upper mediastinal (level VII) or the level IV nodes.
Blood supply: The arterial blood supply to the supraglottic larynx is derived from the superior laryngeal artery, a branch of the superior thyroid artery; the lower half of the larynx is supplied by the inferior laryngeal branch of the inferior thyroid artery.
Nerve supply: Sensation above the vocal fold is supplied by the internal branch of the superior laryngeal nerve, whereas the external branch provides motor supply to the cricothyroid muscles. Both sensory and motor innervations below the vocal fold are provided by the recurrent laryngeal nerve.
EARLY SUPRAGLOTTIC CANCER
Supraglottic squamous cell cancers comprise 30% to 40% of laryngeal cancers in the United States (5,19). The lesions are often silent in their early stages and may present with non-site-specific symptoms such as a sore throat or referred otalgia. Persistent dysphagia or aspiration does not usually manifest until the primary tumor attains significant bulk. Due to abundant lymphatic outflow, an enlarged metastatic neck node is another mode of presentation for early supraglottic tumors. The incidence of cervical metastasis at presentation, however, depends upon the T stage, location, and differentiation of the primary tumor and is reported to vary from zero to approximately 33% in T1-T2 tumors (20).
Surgical Pathology
Whole-organ laryngeal section studies (21,22) and numerous clinical observations (23,24,25) have postulated the supraglottic larynx as a distinct anatomic laryngeal subunit, above the true vocal cords. This compartmentalization is partly attributed to separate embryologic derivations, with the supraglottic structures emanating from branchial arches III and IV (buccopharyngeal anlage) and the glottic-subglottic structures from branchial arch VI (tracheopulmonary anlage). However, no specific anatomical structure has been identified that might act as a barrier between the supraglottic and glottic regions (23).
Early tumors spread within the confines of the supraglottic unit. This concept combined with an understanding of the key avenues of extension, makes supraglottic laryngectomy (SGL), endoscopic or open, a highly effective option for treatment of early-stage cancers. Infrequently, invasion of the glottis can occur when the tumor of the epiglottic petiole extends inferiorly or when extension from the undersurface of the false cord reaches the ventricle.
A certain subset of tumors arises in the (infrahyoid) angle between the epiglottis and the anterior false cord. Dubbed “engelkarzinom” by our German colleagues, this presentation may have considerable deep extension toward or into the PES.
The epiglottic perichondrium and the thyroepiglottic ligament limit anterior extension, but the tumor spreads into the fatty areolar tissue of the PES via infiltration through the epiglottic cartilage fenestrations. Involvement of PES implies a T3 stage, but insidious extension in this direction can occur in early supraglottic lesions, particularly if the tumor originates in the infrahyoid epiglottis. In the PES, there is a transition of the tumor edge from “infiltrating” to broad, “pushing” type with a pseudocapsule, probably arising from the expanded epiglottic perichondrium (21). A tumor-free space usually exists between the hyoid bone and the advancing front of the tumor, a feature that makes preservation of the hyoid in SGL oncologically safe and functionally superior. In late tumors, extralaryngeal spread occurs when extension is observed anteriorly from the PES, breaching the thyrohyoid membrane, sometimes reaching the strap muscles. Another late route of extralaryngeal spread is through the hyoepiglottic ligament to the vallecula and tongue base superiorly. Deep lateral extension of the supraglottic tumor to the thyroid cartilage is rare; ossified cartilage has higher susceptibility to invasion. Lesions of the aryepiglottic fold may spread laterally to involve the medial wall of pyriform sinus.
Staging and Treatment Planning
A complete workup to assess the patient, the subsite and stage of primary tumor, and the presence of cervical lymphadenopathy is indicated (Table 123.1). This includes a thorough history and physical examination, including neck palpation and fiberoptic laryngoscopy. This affords direct visualization of the tumor extent, arytenoid involvement, and cord mobility. Cord hypomobility implies paraglottic space invasion, and cord fixation upstages the primary tumor to T3.
Assessment of comorbidity, particularly, pulmonary diseases, is a crucial component of preoperative planning for conservation surgery. Patients with poor pulmonary reserve, as determined by forced expiratory volume in one second (FEV1) of greater than 75% or FEV1/FVC (functional vital capacity) ratio of less than 65%, are at greater risk of troublesome aspiration.
For T2 lesions, radiologic evaluation with computed tomography (CT) or magnetic resonance imaging (MRI) is performed to determine the extent of the primary and to rule out involvement of the PES, the paraglottic space, or the inner thyroid cortex, factors that escalate the T stage. CT, MRI, and especially gray-scale ultrasonography can reliably assess cervical lymphadenopathy, supplemented by ultrasound-guided fine-needle aspiration (FNA), if indicated. The latter is particularly useful in decision making for or against treating the contralateral neck (see “Management of the Neck”). Chest radiography, CT, or positron emission tomography (PET) is used to evaluate distant metastasis or second primary tumors in smokers.
Operative direct laryngoscopy should be performed along with photodocumentation to accurately assess the primary tumor and obtain biopsies for diagnosis and/or mapping in postradiation, recurrent cases. It also provides the opportunity to determine the suitability for a conservation procedure and decide the ideal approach—transoral or open. Occasionally, exophytic bulk conceals the accurate determination of the inferior tumor extent, whereupon rigid telescopes may be helpful. To detect synchronous primaries, a complete examination of the upper aerodigestive tract (UADT) mucosa is performed.
Treatment
Single-modality therapy with primary surgery or definitive radiotherapy (RT) are the two alternative treatment approaches for early supraglottic tumors. RT alone,
however, is less effective for local control (26), and high laryngectomy rates (14% to 31%) for recurrent tumors (27,28) have made this option less acceptable than primary surgery. T1 and T2 primaries are amenable to curative treatment by conservation surgery with an optimum oncologic control and minimal functional morbidity. Total laryngectomy was the only procedure commonly used for treatment of supraglottic cancer until 1946 when Alonso (29) first described the procedure of SGL. The SGL technique was later refined by Joseph Ogura in 1958 (30) and Max Som in 1959 (24). The modern paradigm of conservation surgery for supraglottic tumors, however, is minimally invasive, endoscopic transoral laser microsurgery (TLM), first introduced by Vaughan et al. in 1978 (31) and further popularized by Davis et al. (32) and Steiner (33,34,35,36). Numerous publications within the last two decades on TLM for supraglottic tumors demonstrate evidence of both comparable (or superior) survival rates and functional preservation rates compared to open surgical procedures. This makes TLM a widely preferred surgical tool in the armamentarium of organ preservation treatment for supraglottic cancer (37,38). Limited reports of technical feasibility also now exist for use of the da Vinci robotic surgical system (39).
however, is less effective for local control (26), and high laryngectomy rates (14% to 31%) for recurrent tumors (27,28) have made this option less acceptable than primary surgery. T1 and T2 primaries are amenable to curative treatment by conservation surgery with an optimum oncologic control and minimal functional morbidity. Total laryngectomy was the only procedure commonly used for treatment of supraglottic cancer until 1946 when Alonso (29) first described the procedure of SGL. The SGL technique was later refined by Joseph Ogura in 1958 (30) and Max Som in 1959 (24). The modern paradigm of conservation surgery for supraglottic tumors, however, is minimally invasive, endoscopic transoral laser microsurgery (TLM), first introduced by Vaughan et al. in 1978 (31) and further popularized by Davis et al. (32) and Steiner (33,34,35,36). Numerous publications within the last two decades on TLM for supraglottic tumors demonstrate evidence of both comparable (or superior) survival rates and functional preservation rates compared to open surgical procedures. This makes TLM a widely preferred surgical tool in the armamentarium of organ preservation treatment for supraglottic cancer (37,38). Limited reports of technical feasibility also now exist for use of the da Vinci robotic surgical system (39).
TABLE 123.1 DIAGNOSTIC APPROACH TO EARLY SUPRAGLOTTIC AND GLOTTIC CANCERS | ||||||
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SURGERY
Endoscopic Procedures
Transoral Laser Microsurgery
The concept of endoscopic management of supraglottic cancer dates back to 1939 when Jackson and Jackson (40) first described the use of the laryngoscope for resection of cancer of the suprahyoid epiglottis (Figs. 123.1A, 123.2, and 123.3). Coupling of the carbon dioxide (CO2) laser to the operating microscope in 1969 by Strong and Jako (41) heralded the advent of TLM. The basic technique of transtumoral cuts to assess the depth of disease and multibloc transoral laser resection is distinct from the timehonored principle of en bloc tumor resection, espoused in open techniques, where exposure of large surface areas of dissected tissue occurs. The transoral approach, however, makes it possible to resect the primary tumor with optimally cleared histologic margins and, at the same time, preserve the anatomical and functional integrity of the noninvolved, surrounding tissue. The resection can be tailored according to tumor location and extension. A classification of different types of endoscopic SGL has been described by the European Laryngological Society (ELS) (Table 123.2) (42). The fundamental requirements for TLM include careful training in technique, knowledge of site-specific “inside out” anatomy, good endoscopic access, and strict enforcement of laser-specific precautions in the operating room.
Contraindications: The major contraindication to TLM for early supraglottic cancers is inadequate transoral access to the entire tumor. We have proposed 8 ‘T’s (45) as limitations of endoscopic access: teeth (prominent), trismus, transverse dimensions (narrow mandibular arch), tori (mandibular), tongue (bulk), tilt (atlanto-occipital extension), treatment (prior radio- or chemoradiotherapy), and tumor (site and size). Once adequate exposure is obtained, there are few technical constraints in terms of curative resection with TLM, even in the presence of intraoperative upgrade of T2 tumors to T3, secondary to spread into the preepiglottic or paraglottic space, glottis, arytenoid, or thyroid cartilage. A further contraindication is disease that requires bilateral arytenoid resection, which causes a high
potential for defunctionalization of safe swallowing, especially in context of poor pulmonary reserve, other major comorbidities, or compromised performance status.
potential for defunctionalization of safe swallowing, especially in context of poor pulmonary reserve, other major comorbidities, or compromised performance status.
 Figure 123.1 Supraglottic Laryngectomy. A: Incisions for TLM (red) and open horizontal (black) procedures, sagittal view. B: External incisions for open horizontal procedure. Note less resection of normal structures in TLM. Extensions (dotted line) in either technique may include hyoid and/or arytenoid. |
Surgical technique: After induction of anesthesia and intubation with a 5-mm inner diameter (preferable) laser endotracheal tube, the usual safety precautions are observed for protection of eyes and face of the patient. An Aquaplast mouth guard is fashioned to protect the patient’s teeth and upper gingiva. Optimum visualization of the operative site is obtained with introduction of laryngoscopes, standard tubed or bivalved, for example, Steiner, Weerda, Kleinsasser. The laryngoscopes may need to be changed or repositioned during the procedure for a satisfactory exposure. Transoral resection is performed with a CO2 laser beam delivered either via micromanipulator or a handheld device, although rapid debulking may initially be performed with electrocautery. For margin management, the high-precision and relatively bloodless cutting characteristics of laser, under high magnification, facilitate clear intraoperative distinction between tumor and normal tissue. Surgical techniques specific to tumor size and subsite are described below.
 Figure 123.2 Incisions for multibloc TLM resection of supraglottic tumor. Blocs 1-4 are removed in numerical order. |
Suprahyoid epiglottis: Small and well-circumscribed primaries may be resected en bloc for efficiency of margin evaluation. For larger lesions, the epiglottis is divided sagittally from superior to inferior, followed by lateral cuts across the vallecula, lateral pharyngoepiglottic fold, and the epiglottis, bilaterally if necessary, to complete resection of the tumor. Wide resection margins can be obtained at this site without swallowing morbidity.
Infrahyoid epiglottis: Early primaries of the infrahyoid epiglottis need to be addressed with caution because of close proximity to the PES. However, some tumors may be “keyholed” out of the epiglottis by excising a disc of mucosa and epiglottic cartilage containing the disease, with perichondrium, using the preepiglottic fat as the deep margin. When the disease is more extensive across the laryngeal surface of the epiglottis, the suprahyoid epiglottis may
be split sagittally (Fig. 123.2) and an ipsilateral hemiepiglottectomy performed. A second, medial to lateral cut is made in the nadir of vallecula to incise around the epiglottis with adequate margins of at least 5 mm. As this incision progresses to transect the lateral pharyngoepiglottic fold, identification of the superior laryngeal artery and/or its branches may be necessary. When identified, they should be clipped before division, failing which they may retract into the lateral soft tissues. Incisions are further made laterally, until the hyoid is reached, to detach the specimen and also partially excise the fatty areolar tissue in the PES. This is facilitated by application of neck pressure applied externally on the larynx to bring the hyoid into laryngoscopic view.
be split sagittally (Fig. 123.2) and an ipsilateral hemiepiglottectomy performed. A second, medial to lateral cut is made in the nadir of vallecula to incise around the epiglottis with adequate margins of at least 5 mm. As this incision progresses to transect the lateral pharyngoepiglottic fold, identification of the superior laryngeal artery and/or its branches may be necessary. When identified, they should be clipped before division, failing which they may retract into the lateral soft tissues. Incisions are further made laterally, until the hyoid is reached, to detach the specimen and also partially excise the fatty areolar tissue in the PES. This is facilitated by application of neck pressure applied externally on the larynx to bring the hyoid into laryngoscopic view.
 Figure 123.3 Endoscopic image of T2 supraglottic tumor, (A) pre- and (B) post-TLM resection. |
TABLE 123.2 ELS CLASSIFICATION OF ENDOSCOPIC SURGERIES FOR EARLY SUPRAGLOTTIS AND GLOTTIS CANCER | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Should there be PES involvement, this tissue is completely excised by advancing the dissection caudal to the hyoid and peeling tissue off the inner thyrohyoid membrane until the superior border of the thyroid cartilage is identified. The dissection is continued further anteroinferiorly, along the thyroid inner perichondrium, past the midline thyroid notch to reach the level of the petiole immediately above the anterior commissure.
To facilitate removal of inferior tumor or remaining epiglottis, a mucosal incision is made across the aryepiglottic
fold and extended inferiorly to cross the false cord, then proceeding anteriorly in the ventricle toward the midline, allowing removal of the remaining epiglottis. These incisions are made uni- or bilaterally according to tumor distribution.
fold and extended inferiorly to cross the false cord, then proceeding anteriorly in the ventricle toward the midline, allowing removal of the remaining epiglottis. These incisions are made uni- or bilaterally according to tumor distribution.
False cord: Tumors at these sites can be completely resected using similar TLM techniques. The depth of excision is determined by a transverse cut through the tumor’s epicenter, and the surface extent of tumor determines the design of the mucosal incisions; inferiorly, the dissection is usually carried to the level of the ventricle or the superior vocal cord. A safe lateral oncologic margin of 5 mm can be obtained for lesions confined to the false cord without any significant functional impairment. However, the inferior deep margin may be closer (1 to 2 mm) and histologic negativity is confirmed with frozen section.
Aryepiglottic fold: Small and superficial lesions can be excised en bloc. The resection is tailored depending on the tumor extent and any extension to arytenoids or medial hypopharyngeal wall is carefully assessed and addressed. The general principle is to split transversely through the tumor and the fold until sufficient deep tissue margin (2 to 5 mm) is established, followed by appropriately oriented perimeter cuts for mucosal clearance. When necessary, the arytenoid may be shaved away serially from anterior to posterior, leaving the posterior body undisturbed.
Hemostasis: Meticulous hemostasis should be ensured during and at completion of all TLM procedures for supraglottic tumors. Bipolar cautery using the 22-cm Stryker Silverglide bipolar forceps design, directly down the endoscope, is especially useful for mucosal bleeding, common along epiglottic and base of the tongue incisions. Because of proximity to or exposure of the superior laryngeal artery or its branches, hemostasis is critical when the procedure involves transection of lateral pharyngoepiglottic fold or dissection of lateral supraglottic mucosa. This vessel should be doubly or triply clipped at identification during TLM. It is also prudent to clip the superior laryngeal and/or superior thyroid artery during any neck dissection, to further obviate the risk of delayed primary or secondary hemorrhage. Before extubation, the laryngoscope is desuspended to allow for reduction of any temporary hemostatic tamponade, and Valsalva maneuvers are used to stimulate dormant bleeders. A tracheostomy, of course, provides optimal protection against major, unexpected late hemorrhage into the airway.
Frozen section analysis: Meticulous orientation of the specimen by marker (e.g., suture or clip) is recommended before removal from the patient, following which the surgical margin is inked carefully for pathologic analysis. It is incumbent on the surgeon to inform the pathologist that part of the specimen intentionally contains a nonmargin area of tumor cut through. Mono- or multibloc resection is performed until histologically negative margins are secured on frozen section. A minor discrepancy of about 2% (46) has been reported to occur between frozen section and permanent section results, but this can be adequately addressed with margin re-resection using repeat TLM. Heat or crush artifact may sometimes make adequate pathologic determination of the resection margin difficult and the surgeon’s discretion becomes important in such situations to judge the adequacy of the actual extent of margin resection.
Postoperative care: A 3-week course of broad-spectrum antibiotics and antireflux measures is instituted in the postoperative period. Resection for early supraglottic cancer seldom requires prolonged intubation or tracheostomy. Nasogastric feeding is usually avoided for small resections but may be prudent in the initial postoperative period. Rehabilitation measures to improve swallowing with postural modifications and a supraglottic diet are commenced at an early stage. Functional recovery is usually rapid, with return to normal swallowing function within a relatively short period, facilitated by good pain control.
Complications: TLM procedures pose a risk of airway laser fire and methods of prevention include reduction of the inspiratory oxygen concentration to less than 30% (47), use of a laser endotracheal tube, or placement of laserproof covering over nonlaser tubes. There is a risk of secondary hemorrhage following TLM during postoperative day 0 to day 21. This can be obviated by taking adequate precautions during the procedure as discussed above (48). Postresection edema of the remaining supraglottic mucosa, especially on the arytenoids, may compromise the airway in the postoperative period. This often resolves with administration of steroids in limited resection. Tracheostomy is seldom required. Airway obstruction may be more persistent after TLM for radiation-recurrent tumors, sometimes necessitating a tracheostomy or transoral laser resection of edematous supraglottic mucosa. Severe aspiration can result in pulmonary complications but is infrequently seen for early supraglottic tumor resection. Resection of the arytenoid, aryepiglottic fold, or tongue base will increase the risk of aspiration. Extensive defects may result in supraglottic stenosis. Complications due to laryngoscope pressure such as dental and mandibular trauma, pharyngeal tears, tongue swelling, laceration, and numbness or loss of taste may also occur.
Transoral Robotic Surgery
Transoral surgery using the da Vinci robotic surgical system was recently reported to be suitable for performing SGL in humans (38). The three-armed robotic system is said to confer improved, three-dimensional optics and tissue manipulating/cutting maneuverability. However, some optical resolution is lost over a high-quality operating microscope. The “endowrist” design allows for flexibility in movement at the end of the robotic instruments. However, the arms carrying such flexible working tips are straight, are rigid, and cannot be maneuvered down a laryngoscope, necessitating spatulate retraction of the tongue. In reality, laryngoscopic exposure may be required to obtain
optimum exposure and the rigid robotic arms cannot be used inside laryngoscopes, needing approximately 30 degrees of axial offset angle to work through the mouth and pharynx. Furthermore, with a 12-mm diameter endoscope for viewing plus two 8-mm (or 5-mm) surgical arms and a suction device, there is significant instrument crowding that currently limits this instrument’s application in supraglottic tumors.
optimum exposure and the rigid robotic arms cannot be used inside laryngoscopes, needing approximately 30 degrees of axial offset angle to work through the mouth and pharynx. Furthermore, with a 12-mm diameter endoscope for viewing plus two 8-mm (or 5-mm) surgical arms and a suction device, there is significant instrument crowding that currently limits this instrument’s application in supraglottic tumors.
As a fledgling transoral approach, the setup time, expense, and compatibility issues of transoral robotic surgery (TORS) with the routine operating requirements, such as neck dissection, confine its niche to select treatment centers. Currently, the robot appears to offer no advantage over endoscopic laser resection although its application in supraglottic tumors may increase with future refinements.
Open Conservation Procedures
“Open” SGL entails resection of the epiglottis, false cord, aryepiglottic folds, hyoid, and upper half of the thyroid cartilage. It includes complete resection of PES. This procedure spares the true cords, at least one arytenoid, and the tongue base, structures that are vital to phonation, respiration, and deglutition, and also avoids the need of a permanent tracheostomy. In early-stage tumors, the basic SGL can be modified to preserve the hyoid bone. “Extended” SGL may be performed for lesions extending to vallecula, tongue base, ipsilateral arytenoid, and medial wall of pyriform sinus. A tracheostomy is always required at the time of resection.
Contraindications: Paraglottic space involvement, cord fixation, thyroid cartilage invasion, bilateral arytenoid or interarytenoid space involvement, tumor extension to the pyriform sinus apex, and extensive tongue base involvement are contraindications for open SGL. The procedure is also contraindicated in patients with poor motivation and respiratory insufficiency.
Surgical technique: A preoperative laryngoscopy is performed to reassess the extent of primary tumor and a preliminary tracheostomy is secured. An apron incision is made and subplatysmal flaps are raised. The hyoid bone is skeletonized and infrahyoid muscles are detached from the body and greater cornua of the hyoid, in preparation for the superior pharyngotomy. The greater cornu should be skeletonized with care because of proximity to the hypoglossal nerve.
The superior thyroid neurovascular pedicle is divided and ligated on the side of the tumor and the constrictors are separated from the posterior edge of the ipsilateral thyroid ala. An incision is made through the perichondrium along the superior border of the thyroid cartilage and a perichondrial flap is reflected inferiorly below the level of the true cord, thus exposing the upper two-thirds of the thyroid cartilage. The thyroid cartilage is transected horizontally just above the midpoint between the thyroid notch and lower border including the superior cornu on the tumor side. The incision is extended horizontally across to the other side or obliquely to preserve the contralateral superior cornua of the thyroid cartilage.
The pharynx is entered superiorly infrahyoid, through the vallecula if the tumor is confined to the supraglottic larynx. For tumors with extension to the vallecula, a suprahyoid or lateral pharyngotomy approach through the contralateral pyriform sinus is utilized. The epiglottis is delivered outward through the pharyngotomy and retracted to visualize the laryngeal introitus. Connecting mucosal incisions are made through the aryepiglottic folds on both sides, anterior to the arytenoids. The cuts are extended through the posterior part of the false cords into the ventricle and connected to the thyroid cartilage incisions to complete resection. An inferior margin of about 2 to 3 mm normal mucosa has been found to be adequate to prevent recurrence at the glottic level (49). Resection of all supraglottic mucosa including uninvolved false cord is recommended to prevent postoperative edema. The role of cricopharyngeal myotomy in SGL for better swallowing outcomes lacks consensus.
After securing complete hemostasis, the defect is reconstructed by suturing the thyroid perichondrial flap to the deep musculature of the tongue base with 3-0 Vicryl. A second reinforcing layer is created by suturing the suprahyoid muscles to the cut edges of infrahyoid musculature. The neck incision is closed after placement of a closed suction drain. The tracheostomy tube is reinserted through a separate incision in the lower skin flap and care is taken to isolate the stoma from the major resection wound in order to prevent contamination of the neck.
Postoperative care: Routine care of wound, tracheostomy, and neck drain is instituted. Feeding is initiated through a nasogastric tube. As the postoperative edema resolves, the tracheostomy cuff is deflated, and depending upon the patient’s tolerance and absence of signs of aspiration, a decannulation trial is commenced. Intensive swallow rehabilitation is initiated under supervision, with a “supraglottic” diet initially followed by a normal diet as judged by the patient’s ability to swallow without difficulty or aspiration.
Complications: Severe aspiration after SGL can lead to recurrent aspiration pneumonia. Intractable life-threatening aspiration, particularly in patients undergoing extended SGL for tongue base or arytenoid involvement, may require a functional total laryngectomy. Hemorrhage, infection, accidental decannulation, and subcutaneous emphysema are other possible complications.
Supracricoid Laryngectomy
Supracricoid laryngectomy (SCL) was first introduced by Majer and Reider in 1959 as a conservation procedure for laryngeal cancer with later refinements in the procedure proposed by Labayle, Bismuth and Piquet (50). It entails en bloc resection of the PES, paraglottic space, and thyroid
cartilage, yielding outcomes comparable to total laryngectomy in selected cases but preserving functions of phonation and deglutition without a permanent tracheostoma. The indications of SCL in T2 supraglottic cancers are lesions that are not ideal candidates for SGL by the virtue of their extension to the ventricle, the anterior commissure, or the glottis with or without impaired cord mobility.
cartilage, yielding outcomes comparable to total laryngectomy in selected cases but preserving functions of phonation and deglutition without a permanent tracheostoma. The indications of SCL in T2 supraglottic cancers are lesions that are not ideal candidates for SGL by the virtue of their extension to the ventricle, the anterior commissure, or the glottis with or without impaired cord mobility.
Contraindications: Invasion of the cricoid cartilage, bilateral arytenoid involvement, extension into the base of the tongue, vallecula or hypopharynx, and fixation of arytenoids are contraindications for SCL.
Surgical technique: A direct laryngoscopy is recommended at the onset for reevaluation of the tumor and its suitability for resection with SCL. After adequately skeletonizing the larynx, the inferior constrictors are incised along the lateral border of the thyroid cartilage followed by release of the pyriform sinuses from the inner thyroid cartilage. The external thyroid perichondrium is preserved bilaterally. During division of the superior laryngeal vascular pedicle, care is taken to preserve the internal branch of the superior laryngeal nerve. The cricoarytenoid joints are disarticulated with care bilaterally to preserve both recurrent laryngeal nerves, which lie just medial and posterior to this joint. A cricothyrotomy is performed just immediately above the cricoid following which ventilation continues through this new opening.
The pharyngotomy is performed by entering the vallecula on the uninvolved side, grasping and retracting the epiglottis through the vallecular incision. Sharp dissection is continued alongside the epiglottis to the aryepiglottic fold and in front of the arytenoid bilaterally, down to the cricoid cartilage and the cricothyrotomy incision, thus releasing the specimen. On the side of the tumor, incisions are made ensuring safe resection margins. If one of the arytenoids needs to be included in the surgical specimen, the incision down the aryepiglottic fold is made posterior to, instead of anterior to, arytenoid on the ipsilateral side.
Before closure, hemostasis is secured and the mucosa is approximated over the arytenoid in a manner that does not limit its movement. To prevent posterior prolapse of arytenoid, a single 3-0 Vicryl suspension suture is passed through the arytenoid, anchoring it forward to the cricoid cartilage. Neck extension is removed to perform laryngoplasty by approximating the cricoid and hyoid using interrupted, nonabsorbable 1-0 Vicryl sutures passed submucosally, one in the midline and one 1 cm on either side of the midline. Tightening of these cricohyoidopexy (CHP) sutures brings the arytenoids(s) closer to the tongue base. This facilitates vibration of the mucosa over arytenoids(s) against the tongue base, a mechanism that is responsible for phonation in these patients.
Once the trachea has been stretched up by the CHP, tracheostomy is performed at an appropriate site that allows the tube to exit skin through the neck incisions. The inferior and superior margins of strap muscle flaps are approximated to reinforce the CHP area. Neck incisions are closed after placement of suction drains.
Postoperative care: Routine care of wound, tracheostomy, and neck drain is instituted in the postoperative period. The patient is nursed in a position that ensures that the head is flexed toward the chest. Feeding is initiated through a nasogastric tube or a gastrostomy in the immediate postoperative period followed by swallow rehabilitation exercises. A decannulation trial is commenced after 6 weeks provided there are no symptoms of aspiration and good airway is maintained. Voice therapy is initiated after completion of wound healing.
Complications: Aspiration occurs commonly after SCL resulting in morbid pulmonary complications such as atelectasis and pneumonia (51). Older patients (greater than 60 years), chronic airway disease, smoking status, extent of arytenoid resection, and CHP are some of the factors associated with a greater risk of postoperative pulmonary complications. More frequent rates of aspiration have been observed in CHP versus cricohyoidoepiglottopexy (CHEP), possibly because of the absence of epiglottis and inadequate neoglottic closure in the former. Precautions recommended for prevention of aspiration are preservation of the superior laryngeal nerves, anterosuperior suturing and positioning of the cricoarytenoid unit, early decannulation, and early onset of swallowing rehabilitation (52). Hemorrhage, infection, wound dehiscence, accidental decannulation, subcutaneous emphysema, and pharyngocutaneous fistula are other possible complications.
Management of the Neck
Clinically or radiologically positive neck disease requires the patient to undergo neck dissection. Ipsilateral N+ necks require ipsilateral dissection, and bilateral or contralateral N+ necks require bilateral neck dissection. Neck dissection is performed at the same operative session as primary tumor resection, although a staged contralateral neck dissection may be carried out later if the ipsilateral neck was pathologically positive. Selective, lateral dissection of levels II, III, and IV is an effective and adequate procedure for management of the neck in early supraglottic cancer. For T1-T2 cancer of the infrahyoid epiglottis or lesions crossing midline, our preferred approach is to carefully assess the neck for ipsilateral and contralateral cervical metastasis by office ultrasound ± ultrasound-guided FNA.
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