Cancers of the larynx are common, and diagnosed following the onset of hoarseness, or throat discomfort, usually experienced over the period of at least a couple months where it is clear it is not related to a cold or infection. Chronic exposure to tobacco smoke is a strong risk factor for developing cancers of the larynx. However, cancers do arise in individuals with no past smoking history. Other exposures may relate to this, such as chronic chemical fume inhalation, or chronic infectious/inflammatory conditions, such as human papilloma virus infection. Most commonly, larynx cancer arises from the surface skin, or epithelium, and is called a squamous cell carcinoma. Other types of cancers, such has salivary gland tumors, lymphoma, or sarcoma are seen, though relatively rarely – and typically these have rather unique management considerations, which will not be discussed further here. When a patient presents to an otolaryngologist—head and neck surgeon with a complaint related to the throat, typically an in-office exam called flexible laryngoscopy (nasal pharyngolaryngoscopy) is performed, where a small flexible video endoscope passed through the nostril to the back of the throat (with a very small amount of topical anesthetic if needed) allows visualization of the vocal cords and larynx structures. This examination will either reassure that no abnormality is present, or that a suspicious appearing finding is present. A CT or MRI of the neck can also be very helpful in some cases in identifying the presence or extent of an abnormality, depending on the symptoms of the individual patient.
If a concern on the larynx is identified, a biopsy will need to be done, to obtain a small portion of tissue to make a diagnosis of the lesion, differentiating between benign versus malignant (cancer). Depending on the shape and position of the lesion and the particular circumstances, sometimes a biopsy procedure can be done at the same time in the clinic room, with further topical medication for numbing the throat. Otherwise, this biopsy procedure, called a direct laryngoscopy, is scheduled under general anesthesia. During this procedure, a rigid metal tube is placed through the mouth to hold back the surrounding throat tissues and expose the areas which need to be examined – typically a fairly systematic and thorough examination of the entire throat and larynx will be conducted as a matter of routine, in addition to specific attention given to the lesion of interest. A biopsy is obtained, which is a very small portion of the tissue on the surface of the throat, measured on the millimeter scale. The pathologists will evaluate this, and deliver a final histopathology diagnosis. The biopsy procedure itself is usually not extensive enough to definitively treat the lesion.
If a cancer of the larynx is diagnosed, and the lesion is considered small (or early) then there are usually two options for further treatment: endoscopic surgery with complete excision, or external beam radiation. The surgical procedure is considered minimally invasive surgery, as the surgery is done via the mouth without external neck incisions. There are several different tools or equipment setups which could be utilized, depending on the exact location and unique characteristics of patient/cancer. So, for example the procedure may include microdirect laryngoscopy with CO2 laser to excise a vocal cord lesion; or, a transoral robotic surgery (TORS) approach to excise a supraglottic lesion. In deciding whether to pursue surgery for an early larynx cancer, there are many factors to consider regarding the patient and the tumor. Surgery is ideal if the lesion is well defined and visible and can be encompassed within the limits of a superficial surgical resection. Critically important to the minimally-invasive endoscopic approach is creating exposure which provides clear view of and working space around the entire cancer. It is not uncommon for the exposure of the lesion to be not possible or limited for a number of reasons, and not be possible to perform the intended procedure. The preceding direct laryngoscopy biopsy procedure will usually give a good indication of whether the exposure is adequate enough to attempt an endoscopic excision procedure. If the endoscopic exposure is not adequate, the alternative treatment of radiation is very reasonable, and is preferential instead of an inadequate surgical resection. If surgery is done, the lesion will be removed in entirety with a small rim of normal tissue completely surrounding it at all margins, which the pathologist can assess microscopically and confirm that the cancer has been excised in entirety. The wound on the larynx surface following surgery heals secondarily, just as tissue scabs over and heals on other skin sites. There are expected sequelae, including temporary soreness, weakness and hoarseness of the voice and other changes, but these are typically well tolerated and not severe. Specifically for supraglottic cancers (but not typically for glottic cancers) there is a period of time of difficulty swallowing and possibly aspiration, which needs to be managed judiciously with diet adjustments and slow careful swallowing.
Endoscopic surgery is an appropriate option to consider for some vocal cord cancers staged as T1, and for supraglottic cancers staged T1 or T2. The T-staging of the cancer is not a sufficient criteria to indicate that surgery is possible or appropriate, and usually a cancer needs to be specifically evaluated by the expert surgeon who will perform the procedure, as the unique characteristics will determine whether a surgical approach is the best route for an individual patient or not. For cancers of the supraglottic larynx (but not for early glottic cancer), an elective neck dissection is appropriate, to remove and biopsy the at-risk lymph nodes from certain levels of the neck, as the risk of microscopic node metastasis is high enough to warrant this prophylactic step. As a rare but significant complication of the supraglottic surgery is bleeding in the throat, while performing the neck dissections the major blood vessels entering the supraglottic larynx are sealed pre-emptively to prevent a major bleeding risk. Other sequelae of neck surgery, such as pain, shoulder weakness, skin numbness are likely but are typically well tolerated. Based on the pathology results from surgery, other adjuvant treatments may be considered to afford the best long term chance of cancer control. Endoscopic surgery on the larynx is ideal when the disease has stayed localized to the larynx and has not spread -- and does not need any further radiation treatment, which leads to other sequelae and problems – if the tumor is completely removed with surgery, no further treatment is needed and the risk of it recurring is very low.
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