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Early-Stage Laryngeal CancerBy Sunni Hosemann Introduction A patient who develops laryngeal cancer has a great deal at stake in terms of speech and swallowing function and thus quality of life. Fortunately, when laryngeal cancer is detected early, the patient has treatment options that can effectively control the disease, often without causing a significant loss of function. Early-stage laryngeal cancer is defined here as a tumor that is confined to the larynx and has not invaded adjacent structures or spread to lymph nodes in the neck. The current standard treatment for such tumors is partial laryngectomy or radiation therapy. While both approaches provide similar medical outcomes, individual patients may find one approach more suitable than the other. Understanding the larynx The larynx is a delicate organ. “It has a complex, layered microanatomy of nerves and muscles that help it move in exquisite ways,” explained F. Christopher Holsinger, M.D., an assistant professor in the Department of Head and Neck Surgery at M. D. Anderson. The larynx’s intricate and complex arrangement of cartilage and muscle is responsible for voice and also partly for breathing. Additionally, the organ’s sphincter makes swallowing possible, prevents aspiration, and stabilizes the thorax by shutting against exhalation during lifting. The three anatomic areas of the larynx—the glottis, supraglottis, and subglottis—have differences in physical makeup, function, and lymphatic drainage. Accordingly, the symptoms of laryngeal lesions tend to vary depending on their location, as do the treatment and prognostic implications. The glottis, the midsection of the larynx, contains the true vocal cords. Glottic lesions cause easily recognized symptoms, the most common being hoarseness. Because of that and because the area has relatively little lymphatic drainage, neoplasms in the glottis are often found at early, curable stages, before they have spread to lymph nodes. The supraglottis, located above the glottis, contains the intricate muscle fibers that control the vocal cords; this area also includes the epiglottis, a cartilaginous flap that protects the airway by closing during swallowing. Supraglottic lesions often do not produce early symptoms. These lesions are also close to a rich lymphatic network, and many patients with supraglottic lesions present with lymph node involvement. The subglottis comprises the throat tissue below the glottis that leads to the pharynx. As do lesions of the supraglottis, subglottic neoplasms often develop without early symptoms and tend to be more advanced on presentation than glottic lesions. According to the National Comprehensive Cancer Network, 60%–65% of laryngeal cancers occur in the glottis, 30%–35% occur in the supraglottis, and about 5% occur in the subglottis. The majority are squamous cell carcinomas, arising from the tissues covering the structures in the larynx. Initial evaluation When a patient presents with a laryngeal neoplasm, careful evaluation by a multidisciplinary team is necessary. The pretreatment workup includes a comprehensive physical examination, laboratory and imaging studies, and an endoscopic examination of the larynx to fully assess the extent of the tumor. At M. D. Anderson, the evaluation also includes laryngeal videostroboscopy, an endoscopic procedure in which video and sound recordings of the larynx are made while the patient vocalizes specific sounds. Videostroboscopy uses stroboscopic illumination that gives the impression of a slow-motion view when the recording is played, allowing the examiner to visualize the vibration of the vocal folds during phonation. Videostroboscopy provides a dynamic image of how the vocal folds close and the symmetry of structure and movement. It can also identify vibratory abnormalities that may not be visible to the naked eye, giving important information about the extent to which the tumor has invaded the vocal folds. “This information often helps predict the potential for retaining normal voice and voice quality after the cancer treatment,” said Jan S. Lewin, Ph.D., an associate professor in the Department of Head and Neck Surgery and director of the Section of Speech Pathology and Audiology. Laryngeal videostroboscopy and analysis of sound production are routine assessments for patients with tumors in the larynx. The examinations are performed at baseline, before treatment begins, and after treatment has been completed. Sometimes, the tests are also performed during treatment to help monitor the patient’s response to treatment and the effect of treatment on vocal function. In any case, videostroboscopy and laryngeal function tests provide important information that helps determine the cancer treatment that will best preserve function in the long term. The tests help clinicians predict the effects of cancer treatment and identify rehabilitative strategies that will best preserve the voice, Dr. Lewin said.
Dental and swallowing evaluations are also part of the pretreatment workup. Such evaluations help identify a patient’s risk for dysphagia and aspiration, which can affect treatment choice, and provide a guide for post-treatment rehabilitation. Like vocal function tests, a thorough swallowing evaluation will help determine which treatment might cure the disease while best preserving function. Testing should be completed before treatment decisions are made, as pretreatment swallowing abilities are often helpful in predicting long-term swallowing abilities beyond 1 year after treatment. Treatment choices Radiation therapy For laryngeal cancers, radiation is typically delivered by external beam. At M. D. Anderson, three-dimensional (3-D) conformal or intensity-modulated radiation therapy (IMRT) is used. Both technologies finely focus radiation to a target area, sparing surrounding normal tissues and allowing the tumor tissue to receive higher doses of radiation. The 3-D conformal technique shapes the beam to the tumor target, while IMRT can vary (or modulate) the intensity of the beam as best suited to the target and surrounding normal structures. These technologies are particularly useful for patients whose tumors are near important structures that might be damaged by radiation. Damage to the salivary glands, for example, can result in long-term xerostomia. According to David I. Rosenthal, M.D., a professor in the Division of Radiation Oncology, the radiation oncologist selects the delivery method based on the location and size of the tumor as well as patient factors, with the aim of optimizing tumor treatment while minimizing long-term effects. Patients typically have radiation treatments once, or in some cases twice, each day over a period of 5 1/2–7 weeks. Radiation therapy is considered a standard primary treatment for early-stage laryngeal cancer because it can cure 80%–90% of such tumors while preserving a high-quality voice. Also, patients who have a recurrence after radiation therapy can usually be treated successfully with surgery, boosting the overall cure rate for patients who receive primary radiation therapy to 95%. Surgery The standard surgical treatment for early-stage laryngeal cancer is partial laryngectomy with resection of the entire tumor. Conventional procedures include vertical partial laryngectomy and supraglottic laryngectomy; the choice of the specific procedure depends on tumor location. The preparation for and recovery from partial laryngectomy procedures are similar those for total laryngectomy, but partial laryngectomy requires only a temporary tracheostomy. Conservation techniques that can preserve laryngeal function may also be an option. Supracricoid partial laryngectomy is one such technique. Another type of conservation surgery—transoral laser microsurgery (TLM)—has recently gained acceptance as an alternative to conventional surgery for early-stage (and intermediate-stage) laryngeal cancer. TLM is performed under direct laryngoscopy using a surgical carbon dioxide (CO2) laser beam and aided by a microscope. The use of a CO2 laser is particularly important; water in the body absorbs the light energy in a way that minimizes collateral injury to adjacent neurovascular, mucosal, and muscular structures. According to Dr. Holsinger, TLM represents a truly minimally invasive alternative for some patients. The larynx is accessed via a laryngoscope inserted through the patient’s mouth, so a surgical incision is not needed. The surgeon “follows the tumor” along its anatomic boundaries to assess its margins. The laser vaporizes tissue so that the margins can be seen without carbonization from cautery. For selected patients, Dr. Holsinger points out, the tumor may be divided to identify the depth of invasion and to help the surgeon determine the appropriate extent of resection. This approach certainly challenges the long-held “en bloc” tenet of oncologic surgery, but it allows TLM to be used for larger tumors than would be possible with en bloc resection, given the restricted anatomical spaces of the neck and throat. It should be clarified that TLM is not an ablative procedure but rather a true resection. The tumor can be studied pathologically—an advantage over radiation therapy. TLM offers many other advantages: it is usually a one-time treatment, and it can successfully cure early-stage cancer, but it does not preclude future treatment options—patients can have radiation or additional surgery if the tumor recurs. “It does not burn a bridge,” Dr. Holsinger explained. Also, the recovery time is minimal compared to conventional surgeries; TLM is usually done as a day surgery when used as a primary treatment for early-stage cancers. Most patients are able to speak and eat immediately after surgery and can return to normal activities within a week. Today, most TLM procedures for laryngeal cancer are performed for tumors that have recurred after primary radiation treatment; in such cases, TLM may be an alternative to total laryngectomy. Unfortunately, 70% of the patients with early and intermediate-stage larynx cancer who have a recurrence after radiation will require a total laryngectomy.1,2 Because of its significant advantages, TLM is now considered a primary treatment option for early-stage laryngeal cancer at M. D. Anderson, said Randal S. Weber, M.D., a professor in and chair of the Department of Head and Neck Surgery. Despite those advantages, however, Dr. Weber pointed out that TLM may not be an option for all early-stage laryngeal cancer patients, including those with limited neck mobility or spinal issues that prevent the positioning necessary for the surgery. If a patient has a full set of natural teeth or cannot fully extend the jaw, the surgeon may not be able to use transoral instruments. Treatment decisions The goal of treatment for patients with early-stage laryngeal cancer is optimal cancer control with functional preservation of the larynx, said Dr. Rosenthal. The chosen treatment should be the one that is the easiest on the patient, he added. “Functional preservation” must take into consideration the jobs of this intricate organ: breathing, safe swallowing without aspiration, and voice. Ideally, early-stage laryngeal cancers should be treated with a single modality, either surgery or radiation therapy. The choice between surgery and radiation therapy should be based first on the patient’s medical considerations. For example, patients with a significant comorbid illness are often better served by radiation therapy than major surgery. As noted earlier, anatomical factors may preclude TLM, and comorbidities that cause pulmonary insufficiency or poor healing may preclude all surgical options. The other significant medical variables are tumor size and location. Tumors that are small and localized lend themselves to surgery; for larger lesions, radiation therapy and chemotherapy may provide superior voice results. Patient preferences should also be considered, especially when the patient has no compelling medical considerations besides the tumor itself. More patients have opted for radiation therapy as it has become medically equivalent to surgery. Radiation therapy allows patients to avoid the substantial recovery and rehabilitation periods that follow surgery. Also, radiation therapy generally causes less deterioration in voice than surgery. For larger tumors that involve more structures, radiation therapy may have a significant effect on swallowing function. However, some patients are more comfortable with surgery than radiation therapy, and surgery offers a one-time treatment when it is not feasible to receive daily radiation treatments for up to 7 weeks. The emergence of TLM has significantly altered the decision process for patients who are candidates for surgery or radiation therapy because it is noninvasive, requiring no surgical incision, tracheostomy, or complicated recovery—all reasons that some patients decided against surgery in the past. Patients whose voice quality is important in their work or personal life may prefer radiation therapy to retain the best possible voice after treatment. For others, the time required for radiation therapy weighs more heavily than voice changes, and they may prefer TLM or conventional surgery, both one-time procedures. However, risk to voice depends also on the tumor site. For example, while surgery for glottic cancer can sometimes result in voice changes, there is no voice alteration following TLM for supraglottic cancer. Finally, patients and their physicians should consider the available technical expertise for any of the procedures discussed here. “TLM, for example, requires study, practice, and treating lots of cases,” Dr. Weber said. “It’s not a procedure one can excel at by doing it on an occasional basis.” Likewise, radiation therapy of the head and neck is complex. The National Comprehensive Cancer Network recommends a team consisting of a radiation oncologist, a radiation physicist, a dosimetrist, and a radiation technologist to achieve optimal results from radiation therapy, particularly 3-D conformal techniques. This recommendation is even more important to consider when the patient will not be receiving treatment at a comprehensive cancer center or a facility where multidisciplinary treatment decisions are made. 1 Viani L, Stell PM, Dalby JE. Recurrence after radiotherapy for glottic carcinoma. Cancer. 1991;67(3):577–584 SUGGESTED READING
For more information on this topic or for questions about M. D. Anderson’s treatments, programs, or services, call askMDAnderson at (877) MDA-6789. Other articles in OncoLog, January 2009 issue: Home/Current Issue | Previous Issues | Articles by Topic | Patient Education ©2009 The University of Texas M. D. Anderson Cancer Center |
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