13 Cancer of the Hypopharynx, Larynx, and Esophagus Flashcards
Describe the general anatomic divisions of the larynx.
Describe the general anatomic divisions of the larynx.
Vertically, the larynx is subdivided into three regions: the supraglottis, the glottis, and the subglottis. The division of these three subsites reflects embryologic development and natural barriers to cancer spread. The supraglottis can be thought of as a three-dimensional box containing a suprahyoid and infrahyoid epiglottis, the aryepiglottic folds, arytenoids, ventricles, and false vocal folds. It extends from the superior surface of the epiglottis and the superior edge of the aryepiglottic folds to a horizontal plane passing through the lateral margin of the ventricle and the superior surface of the true vocal folds. The supraglottis has bilateral lymphatic drainage to the upper and middle jugular lymph nodes. The glottis begins at the superior surface of the true vocal fold and extends inferiorly 1 cm. Laterally it is bordered by the thyroid cartilage with the lateral ventricle coming to the superior most extent. It contains the anterior and posterior commissures. The vocal folds themselves have sparse lymphatics, therefore deep invasion is needed for unilateral lymphatic spread. The subglottis begins at the inferior border of the glottis (1 cm below the supraglottis) and proceeds to the inferior border of the cricoid cartilage.
Regarding the divisions of the larynx, where does laryngeal cancer commonly occur?
Regarding the divisions of the larynx, where does laryngeal cancer commonly occur?
Laryngeal cancer most commonly arises in the glottis (60%), followed by supraglottis (35%), and subglottis (2%); another 3% are transglottic and involve multiple subsites. An overwhelming 95% of glottic cancers arise from the true vocal cords. Because of natural barriers to spread and early presenting symptoms, laryngeal cancer is often confined to the larynx at time of diagnosis (60% of cases).
How common is laryngeal cancer?
How common is laryngeal cancer?
Laryngeal cancer is the second most common malignancy of the head and neck (after oral cavity/oropharynx). Currently, in the United States, there are over 12,000 new cases of laryngeal cancer annually. One third of these patients will die from their disease. The number of new cases is declining by roughly 2% to 3% per year due to decreased smoking. Laryngeal cancer is 3.8 times more common in men than women, though the gender disparity has narrowed in recent years due to the increased proportion of female smokers.
What are the risk factors for laryngeal cancer?
What are the risk factors for laryngeal cancer?
Tobacco and alcohol are the primary risk factors for laryngeal cancer. The risk is thought to be directly proportional to the duration and intensity of exposure. Smoking and alcohol are synergistic in increasing cancer risk rather than merely additive. Risk does decrease slowly after cessation but does not return to baseline for at least 20 years. Patients who continue to smoke through their treatment are at a higher risk of recurrence and development of a second primary. There is conflicting data as to whether laryngopharyngeal reflux could be a risk factor, though a causal relationship has yet to be established.
What types of cancers are found in the larynx?
What types of cancers are found in the larynx?
Squamous cell carcinoma (SCC) is the most common type of malignancy found in the larynx, accounting for more than 95% of all tumors. Variations of SCC include verrucous carcinoma (2% to 4%) and spindle cell carcinoma. Verrucous carcinoma carries an improved prognosis while spindle cell variants are more aggressive. Both subtypes are typically treated with surgical excision.
Less common nonepithelial tumors include adenoid cystic carcinoma, mucoepidermoid carcinoma, sarcoma (e.g., fibrosarcoma, chondrosarcoma, liposarcoma), neuroendocrine tumor (e.g., paragangliomas, carcinoid), contiguous lesions (i.e., thyroid), and metastatic lesions.
How might a patient with laryngeal cancer present?
How might a patient with laryngeal cancer present?
Hoarseness, dysphagia, odynophagia, referred otalgia, globus sensation, weight loss, and neck mass can all be presenting symptoms. Glottic cancers tend to present early with hoarseness, whereas airway obstruction and hemoptysis are later findings. Supraglottic cancers often present with dysphagia and odynophagia. Otalgia can occur due to pharyngeal extension. Hoarseness occurs secondary to transglottic extension or arytenoid involvement. Airway obstruction can be gradual with bulky disease, or may be acute in onset from a ball-valve type of obstruction. Supraglottic tumors are usually discovered later and have a poorer prognosis as these symptoms arise with progression beyond the supraglottis. Subglottic carcinomas present with signs and symptoms of early airway obstruction such as biphasic stridor.
Discuss the workup of laryngeal cancer.
Discuss the workup of laryngeal cancer.
History and physical exam should address symptoms such as dyspnea, stridor, dysphagia, odynophagia, otalgia, weight loss, and hoarseness. Special attention should be paid to risk factors for carcinoma, primarily smoking, alcohol, and history of cancer. It is important to determine overall health and functional status as this will play a key role in determining treatment. A complete head and neck exam should be performed with careful visualization and palpation of oral cavity, oropharynx, and neck. Laryngoscopy should be performed with any lesions characterized by location, size, endophytic or exophytic nature, vocal cord mobility, and patency of the airway.
In cases other than a T1 glottic primary, additional imaging should be ordered to evaluate extent of disease and metastatic potential. A computed tomography CT scan of the neck with contrast is the most utilized modality. MRI can also be useful and is more sensitive in differentiating soft tissue and cartilage involvement. PET scan may be helpful in advanced stages for metastatic workup. Operative endoscopy should be pursued with direct visualization, palpation, and tissue sampling. In select cases debulking and/or airway stabilization will also be warranted.
What is the significance of a paralyzed vocal fold?
What is the significance of a paralyzed vocal fold?
A fixed or paralyzed vocal fold is one that appears immobile on exam, and can be associated with hoarseness or aspiration. A cord can be rendered immobile in several ways, including mass effect of the tumor, cricoarytenoid joint involvement, or recurrent laryngeal nerve involvement. Vocal cord immobility upstages laryngeal and hypopharyngeal cancers to T3. This is in contrast to a partially immobile or paretic vocal fold. A vocal fold with decreased mobility is characterized as at least a T2 cancer.
What membranous structures help prevent the spread of cancer outside of the larynx?
What membranous structures help prevent the spread of cancer outside of the larynx?
There are two fibroelastic membranes that help prevent cancer spread from the larynx. The conus elasticus helps support the vocal folds and extends from the cricoid cartilage to the vocal ligaments. It is the lower part of the elastic membrane of the larynx. The quadrangular membrane supports the supraglottis and begins superiorly at the lateral margin of the epiglottis and proceeds inferiorly to the false cords. This is the upper part of the elastic membrane of the larynx. This quadrangular membrane and the conus elasticus are separated by the laryngeal ventricle and form the medial boundary of the paraglottic space (Figure attached).
Discuss the routes of local spread and nodal metastasis of SCC of the different laryngeal regions.
Discuss the routes of local spread and nodal metastasis of SCC of the different laryngeal regions.
Laryngeal cancer may spread by direct extension or through the lymphatics. Local extension may occur through the paraglottic space, which is a fibrofatty-filled space bounded medially by the conus elasticus and quadrangular membrane, laterally by the thyrohyoid membrane and thyroid cartilage lamina, and posteriorly by the medial mucosa of the piriform sinus. Entry of a mass into this space, commonly from the laryngeal ventricle, allows for transglottic extension. Paraglottic space involvement upstages any laryngeal carcinoma to T3. The pre-epiglottic space is a fibrofatty-filled space bounded superiorly by the hyoepiglottic ligament, anteriorly by the thyrohyoid membrane and thyroid cartilage, and posteriorly by the epiglottis and thyroepiglottic membrane. It is continuous laterally with the paraglottic space. Glottic cancer can invade from the anterior commisure along Broyle’s ligament into the thyroid cartilage and via lacunae of the epiglottis into the pre-epiglottic space.
Regional lymphatic spread also occurs. The lymphatics of the supraglottis follow the superior laryngeal arteries draining to the upper and middle jugular lymph nodes in levels 2 and 3. Bilateral lymphatics allow cancer to spread to the ipsilateral or contralateral lymph nodes. The incidence of nodal metastasis varies from 0% to 57% depending on the primary tumor stage. The glottis is without notable lymphatic drainage; regional nodal spread for glottic cancer is below 10%. Subglottic carcinoma extends to and through the cricothyroid membrane to involve the lateral paratracheal and cervical lymphatics as well as the medial prelaryngeal (Delphian) node. There is also rich lymphatic drainage from the postcricoid area.
How is a primary tumor in laryngeal carcinoma staged?
How is a primary tumor in laryngeal carcinoma staged?
Cancers of the larynx are described using the TNM classification system of the American Joint Committee on Cancer (AJCC). Cancers are staged based on their site of origin in the supraglottis, glottis, or subglottis. Regional nodal involvement and distant metastasis are staged similary to other sites in the head and neck
How is laryngeal cancer treated?
How is laryngeal cancer treated?
The patient’s functional status, location of the cancer, and its stage are critical in determining the appropriate modality. Early cancers, defined typically as Stage 1 and Stage 2 lesions, are usually addressed with single-modality therapy. Radiation therapy and surgical excision have been shown to be statistically equivalent in terms of disease-free and overall survival. Advanced laryngeal cancers Stages 3 and 4 should be addressed by multimodality therapy. For high-volume tumors this may mean conservation surgery in select cases or total laryngectomy with postoperative radiation plus or minus chemotherapy. High-level evidence favors combined chemotherapy and radiation over radiation alone as a primary treatment modality for advanced stage cancers.
What are the surgical options for early laryngeal cancer?
What are the surgical options for early laryngeal cancer?
Many early laryngeal cancers may be treated via conservation surgery with excellent local control rates. Traditional surgical resection has included open approaches, but transoral robotic and transoral laser techniques are now more commonly utilized. T1 and T2 lesions are usually amenable to surgery but other factors such as whether the tumor is exophytic or endophytic and the precise location of the tumor are important. Exophytic tumors located on the central portion of the cord or on the epiglottis are more easily excised than endophytic tumors located near the arytenoid or anterior commissure, for instance. Contraindications to conservation laryngeal surgery include: more than 5 mm of subglottic extension, extension into the postcricoid space, involvement of the base of tongue or piriform sinus, cartilage invasion, bilateral vocal cord fixation or bilateral arytenoid involvement. Glottic T1a tumors are treated with cordectomy while larger T1 or T2 lesions may be amenable to vertical partial laryngectomy through an open or transoral approach. Supraglottic T1 and T2 lesions may be treated with supraglottic (horizontal) laryngectomy or supracricoid partial laryngectomy through an open or transoral approach.
What is the difference between horizontal hemilaryngectomy and vertical partial laryngectomy?
What is the difference between horizontal hemilaryngectomy and vertical partial laryngectomy?
In both instances the resection must be oncologically sound with preservation of at least one cricoarytenoid unit (the cricoid cartilage, one arytenoid cartilage, associated musculature, and superior and recurrent laryngeal nerves). Horizontal hemilaryngectomy, or supraglottic laryngectomy, is indicated for early T1, T2, or select T3 supraglottic tumors that do not involve the true vocal fold or associated cartilages. The open procedure removes the bilateral supraglottis but spares the true vocal folds and arytenoids. Voice and swallowing outcomes are typically good. If the tumor involves one vocal fold or cricoarytenoid joint a supracricoid laryngectomy may be performed. This leaves one cricoarytenoid joint intact and removes a portion of the thyroid cartilage. Vertical partial laryngectomy, or hemilaryngectomy, is indicated for T1, T2, and select T3 glottic lesions (not involving commissure or associated cartilages). This procedure removes the ipsilateral vocal fold, false cord, ventricle, and overlying thyroid cartilage. Post-operatively, patients have a functional glottic voice.
What are the subsites of the hypopharynx and important oncologic considerations?
- The piriform sinus is the inferior extent of the hypopharynx. It is typically subdivided into anterior, lateral, posterior, and apical walls. The medial limits of the piriform sinus are the larynx, aryepiglottic folds, arytenoids, and cricoid. The piriform sinus is the most common site for hypopharyngeal cancer (65% to 75%). Cancer may extend from here into the subglottis, thyroid cartilage, postcricoid region, or cricoarytenoid joint. Three of every four patients presenting with hypopharyngeal cancer within the piriform sinus have regional metastasis, resulting in a poorer prognosis.
- The postcricoid space spans from the posterior aspect of the arytenoids to the esophageal introitis, anterior to the posterior pharyngeal wall. Cancer here can directly invade the cricoid and can also involve the recurrent laryngeal nerve by spreading laterally into the tracheo-esophageal groove.
- The posterior pharyngeal wall extends from the level of the hyoid bone to the cricopharyngeus muscle which marks the transition to cervical esophagus. Extension posteriorly through the potential retropharyngeal space can lead to involvement of the prevertebral tissues.
What is the prognosis for laryngeal and hypopharyngeal cancers? Has this improved over the last few years?
What is the prognosis for laryngeal and hypopharyngeal cancers? Has this improved over the last few years?
Survival of patients with laryngeal cancer has not improved over the past several decades. Only early stage glottic cancer carries a good prognosis. Hypopharyngeal cancer survival has increased slightly over the same time period. Unfortunately, most hypopharyngeal and laryngeal tumors present late and thus have poor survival rates.
