Transoral Laser Microsurgery in Carcinomas of the Oral Cavity, Pharynx, and Larynx

Jochen A. Werner, MD, Anja A. Dünne, MD, Benedikt J. Folz, MD, Burkard M. Lippert, MD

Disclosures

Cancer Control. 2002;9(5) 

In This Article

Laryngeal Carcinomas

The surgical, oncologic, and functional principles are the same for minimally invasive surgery as for more conventional resections. The primary objective is the complete resection of the tumor while preserving as much function as possible. The principle is to minimize surgical morbidity while adhering to long-standing oncologic standards.

During transoral laser microsurgery, decisions are made in accordance with the local spread of the tumor. The tumor extension is often clearly apparent under the microscope, and the lesion is resected until healthy tissue is found and appropriate safety margins can be maintained. The goal of complete resection is achieved by variations in the surgical approach and dissection instrument. In general, a transoral approach is the primary choice, and the CO2 laser under microscopic control is used as a dissecting instrument.

All tumor surgery should adhere to the principle of complete resection with clear surgical margins that are histologically documented. This involves the cooperation of both the surgeon and the pathologist. Using a small focal diameter of the laser beam results in minimal carbonization and is particularly suitable for this application. The histologic assessment of the resection margins is facilitated by this technique, despite relatively close margins.[9,10]

The unconventional surgical technique of dissecting through larger tumors during the resection and removing the tumor in parts allows the surgeon to inspect the surface of the tissue under microscopic control. There are no indications that the incidence of late regional or distant metastases increases due to laser incisions through a tumor; this may be explained by the sealing effect of the lymph vessels, which has been observed in previous investigations.[11]

Carcinoma In Situ, Microinvasive Carcinoma, and Small T1a Carcinomas

In cases of a biopsy-proven small carcinomas or carcinoma in situ, the entire lesion is excised with an appropriate resection margin (Fig 5). When tumor invade is found in the resection margin, two treatment strategies are possible: laser surgery or radiotherapy. We recommend repeating laser or conventional surgery because, in most cases where tissue is re-resected from the tumor margin, this tissue is tumor-free on histopathologic investigation, and radiotherapy would have been unnessecary. Our experience indicates that, in general, vocal function is almost normal following such limited-excision biopsies.[12]

Figure 5.

(A) Intraoperative view of a T1a carcinoma of the left vocal cord before laser microsurgical resection and (B) immediately after resection. (C) Two years postoperatively, no recurrent disease can be observed and functional results are satisfactory.

Large T1a and T1b Glottic Carcinomas

When a clearly superficial lesion infiltrates to a depth of only approximately 2 mm and does not cover the entire cord (ie, microcarcinoma), we excise the carcinoma en bloc. When the depth of infiltration is in doubt, a single incision through the center of the tumor may help to estimate the depth. The subsequent laser surgical treatment is the same as for small, well circumscribed lesions. In cases of marginal involvement of the anterior commissure without subglottic extension, the anterior commissure is resected along with the bilateral cord lesion. The dissection is carried out along the thyroid cartilage under high magnification of the operating microscope. Laser surgical resections of carcinomas of the anterior commissure require a surgeon experienced in this technique because the risk of developing recurrent disease is more likely in the anterior commissure than in any other localization of the glottis.[13,14,15]

T2 Carcinomas

For all T2 carcinomas of the glottis, primary laser surgery is advocated regardless of the pattern of tumor spread. Steiner[16] reported that it is of no significance whether the tumor is unilateral or bilateral, whether it extends to involve supraglottis or subglottis, or whether it infiltrates the anterior commissure. Again, a surgeon with wide experience in laser surgery is essential. Superficially spreading carcinomas are ideally suited for laser surgery. Even if they cover vast areas of the endolarynx, they can be resected completely with a partial mucosectomy of the larynx if the carcinoma can be exposed adequately.[17] The excision can be performed in several pieces, and the basal surfaces should be stained with blue ink for better orientation of the pathologist. Exact topographic descriptions on the pathology request form are important and should be copied onto patient charts. Additionally, the exact origin of the individual specimen must be noted in a schematic drawing of the larynx.

T3 Carcinomas

Currently,the majority of resectable carcinomas are treated with conventional surgery.However, laser surgical resection is feasible even for large tumors if they can be exposed adequately and if the surgeon has the required training in laser surgery. For these advanced tumors of the glottis, incisions are placed through the bulk of the tumor to divide it into smaller portions, laterally onto the thyroid cartilage and inferiorly onto the superior surface of the cricoid cartilage. Incisions follow the extensions of the tumor and are placed deeply into the musculature until a tissue layer is encountered that reacts normally to the laser light under the microscope. If the musculature is invaded up to the perichondrium, the tumor can be resected by dissecting along the inner table of the thyroid cartilage. Suspected infiltration of the thyroid cartilage or definite penetration through parts of the cartilage is included in the resection. A specimen resected from the neighboring prelaryngeal soft tissues can be used to verify the completeness of the resection. The resection of extended carcinomas should be performed by a surgeon experienced in laser surgery to avoid an incomplete resection that would adversely affect the patient's prognosis. Conventional surgery is preferred where an experienced surgeon is unavailable.

Supraglottic Carcinomas

Small, well-circumscribed tumors of the supraglottis can be resected in one piece, similar to small lesions on the vocal cord.[12]

Suprahyoid Epiglottis and False Cord Area. Technically, tumors in this location can be easily excised. Wide resection margins can be achieved without functional implications as in the case of glottic lesions.

Infrahyoid Epiglottis. The depth of tumor infiltration in the area around the petiole is difficult to assess preoperatively. There may be considerable difficulty in distinguishing between a T1 tumor and a T3 lesion (infiltration of the pre-epiglottic space). To determine the extent of the carcinoma to the preepiglottic space, we usually split the suprahyoid epiglottis sagitally.The bivalved laryngoscope is subsequently advanced, thus revealing the surface of the dissection plane through the epiglottic cartilage as well as the pre-epiglottic fat and the laryngeal surface of the infrahyoid epiglottis with the tumor. The tumor is then dissected in a sagittal plane. The dissection proceeds in an inferior direction. Depending on the extent of the tumor, horizontal cuts are placed through the bulk of the lesion. If the thyroid cartilage or one of the arytenoid cartilages is infiltrated by tumor, it is included in the resection. During the resection of parts of the thyroid cartilage, care is taken to avoid damage to the extralaryngeal vessels. If the tumor has broken through the thyrohyoid membrane, it is followed as far into the neck as possible. The resection can reach all the way into the subcutaneous tissue of the neck. Persistent functional impairments are not anticipated with this surgery.

Resection of advanced carcinomas requires attention to postoperative function. Resection of one arytenoid cartilage is not associated with long-lasting functional impairment; however, if both arytenoids are resected, deglutition without aspiration is usually not possible. Additional difficulties may occur if further resections in the area of the base of the tongue are required.[18] As already noted, the resection of extended carcinomas is reserved for surgeons with extensive experience with laser surgery.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.

processing....