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Transoral laser microsurgery: applications in head and neck oncology Expert Rev. Med. Devices 6(6), 599–602 (2009)
Guy J Petruzzelli, MD, PhD, FACS Charles Arthur Weaver Professor of Cancer Research; and Professor, Departments of Otolaryngology and Neurosurgery, Rush University Medical Center, 1725 West Harrison, Suite 218, Chicago, IL, USA Tel.: +1 312 942 6100 Fax: +1 312 942 6225
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“Nonendocrine head and neck malignancy is the sixth most common cancer worldwide and the ninth most common cancer in the USA.” The term head and neck cancer includes a biologically heterogeneous group of malignant neoplasms that are derived from the mucosa of the upper aerodigestive tract, the major and minor salivary glands, endocrine and neuroendocrine organs, and soft tissue structures. Nonendocrine head and neck malignancy is the sixth most common cancer worldwide and the ninth most common cancer in the USA [1,2] . Traditional risk factors, such as exposure to tobaccoderived carcinogens, remain the most common cause of squamous cell carcinoma of the mucosa of the upper aerodigestive tract, and wide ethnic and geographic patterns of disease incidence exist [3] . The human papilloma virus has been shown to be associated with the development of squamous cell carcinomas of the oropharynx (tonsil and tongue base) in a younger population, without significant tobacco exposure [4] . In the context of this discussion of transoral laser microsurgery (TLM), I shall limit my comments to the treatment of malignant neoplasms arising from the mucosal surfaces of the upper aerodigestive tract, the vast majority of which are squamous cell carcinomas.
produced by the excitation of molecules of carbon dioxide gas in a closed cylinder. The energy leaves the discharge tube and is directed to the tissue through a series of angled mirrors in an articulated arm and collimated to a focused spot size of 0.25 mm. Recently, a fiber-based delivery system for the carbon dioxide has been developed and approved for clinical applications that is superior to the traditional mirror articulated arm delivery system, particularly in transoral laser microsurgery of oropharyngeal neoplasms [5,6] . The 10,600-nm wavelength of the carbon dioxide laser imparts particular properties that make it most useful in head and neck surgery. The first is that at the laser–tissue interface, the laser energy is transformed into thermal energy that is absorbed, which precisely vaporizes the tissue water and creates the tissue defect. The second is that the depth of penetration of the laser is very superficial and, thus, predictable. Finally, the maximum energy is delivered at the focal length of the laser, which generates an incision, and by defocusing the laser, more superficial photocoagulation and tissue vaporization can be achieved. The differential effects observed at the laser–tissue Carbon dioxide laser: interface (i.e., incision or coagulation) can medical applications be produced by varying the spot size, pulse Space limitations prevent a detailed discus- duration and/or the power of the laser [7] . sion of the development of laser applications in head and neck surgery. The bio- Transoral laser microsurgery: logical properties of a laser and subsequent general considerations laser–tissue interactions are determined by Transoral laser microsurgical techniques the wavelength of the laser, which is ulti- will not be appropriate for all patients with mately a function of the medium used to head and neck neoplasms. Similarly, not generate the laser energy. all head and neck surgeons will develop The carbon dioxide laser is a mono the requisite skill or have sufficient surgichromatic beam of nonionizing UV radia- cal volume to justify the expense for the tion, with a wavelength of 10,600 nm, necessary equipment.
10.1586/ERD.09.49
© 2009 Expert Reviews Ltd
ISSN 1743-4440
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Patient factors that limit the applications of TLM techniques relate to anatomic constraints that reduce exposure of the posterior oropharynx, valeculla and laryngopharynx. Intact dentition, trismus, micrognathia, macroglossia and limited cervical range of motion may inhibit the surgeon’s ability to adequately visualize the tumor and surrounding anatomy. In addition to obstructing the view of the tumor, intact maxillary dentition may limit the placement or ability to open retractors. A detailed history and careful head and neck examination, including flexible fiberoptic and/or angled rigid Hopkin’s rod pharyngolaryngoscopy, are required prior to TLM tumor resection. Some authors continue to advocate the use of a separate staging panendoscopy to assess the 3D anatomy of the tumor.
“A detailed history and careful head and neck examination, including flexible fiberoptic and/or angled rigid Hopkin’s rod pharyngolaryngoscopy are required prior to transoral laser microsurgery, tumor resection.” Careful presurgical clinical and radiographic staging are necessary to determine whether tumor factors that will limit the success of a TLM resection exist. Extension of a tumor into the neck is a contraindication for TLM resection alone, as these tumors may need a combined internal and external approach for safe control of the carotid artery and internal jugular vein. Lateral extension of oropharyngeal tumors into the pterygoid muscles or skull base involvement are contraindications for a TLM resection. Similarly, deep extension of the primary tumor into the base of the tongue or extensive invasion of laryngeal cartilages may limit resectability with purely endoscopic approaches. Finally, advanced cervical metastatic disease with fixation to the carotid artery, deep cervical fascia and skull base remain as traditional contraindications to initial surgical resection. Transoral laser microsurgery is not a technique suited for all surgeons at all centers. Surgeons performing endoscopic resections should have extensive training in open head and neck oncologic procedures such that they can covert to an open operation if required. Open surgery may be necessary to completely resect the tumor, or to control bleeding that cannot be managed endo scopically. A significant amount of patience is required of surgeons employing TLM procedures. To gain satisfactory exposure of particular tumors, several different retractor systems or repositioning of the patient may be necessary. In addition, if the surgeon is using frozen sections to control tumor margins, he or she must be comfortable waiting for those data as well. Some tumors will require multiple surgeries for complete resection; thus, the surgeons should have a low threshold to return a patient to the operating room for pathologic reassessment of the margins. Institutions wishing to support a TLM program must be willing to commit the necessary financial resources to support the acquisition of the correct instruments and retractor systems. Capital resources may be needed to purchase more expensive items, such as the microscope and laser. Finally, institutions offering TLM to oncology patients should do so only in the context of an integrated combined 600
multispecialty head and neck oncology program. Necessary support services, such as speech and swallowing rehabilitation, should be available in the immediate postoperative period. Specific applications of transoral laser microsurgery techniques Laryngeal cancer
The TLM procedure was first reported for the excision of benign lesions and early premalignancy of the larynx in 1973 [8] . The technique gained wide acceptance as the preferred treatment of glottic carcinoma in situ and early cancers since it could be easily repeated, obtained material for pathologic examination, and often spared patients the morbidity and subsequent toxicity of external-beam radiation therapy. Rates of overall and disease-free survival, and laryngeal preservation for patients with early- or even intermediate-stage glottic carcinoma show that TLM-based treatment programs are superior to treatment with definitive external-beam radiotherapy [9] . For intermediate-stage glottis carcinomas, TLM is superior to open approaches (i.e., corde ctomy, laryngofissue or hemilaryngectomy) because it does not require tracheotomy and patients are able to speak and swallow almost immediately postoperatively. Regarding intermediate-stage laryngeal carcinoma, some controversy exists as to whether voice results are better with primary radiotherapy; however, the data remain controversial [10,11] . The success of TLM-based treatment for early glottic tumors provided the basis for expanded applications, including T3 and early T4 glottic tumors with the goal being functional larynx preservation, and avoiding chemoradiotherapy and the attendant swallowing dysfunction. However, in most cases of T3 and all T4 laryngeal tumors, many authors employ primary TLM in combination with postoperative radiation therapy. Voicing following TLM for advance glottis tumors is initially poor but can be improved with secondary medialization laryngoplasty. Patients are more accepting of this result owing to the fact the larynx is intact and permanent tracheotomy is avoided [12] .
“The success of transoral laser microsurgery-based treatment for early glottic tumors provided the basis for expanded applications, including T3 and early T4 glottic tumors, with the goal being functional larynx preservation, and avoiding chemoradiotherapy and the attendant swallowing dysfunction.” In the management of supraglottic cancer, the efficacy and sound oncologic results obtained with open supraglottic laryng ectomy are well established. Improved optics and laser-delivery systems and enhanced exposure of the larynx obtained with bivalved retractors allowed for safe and oncologically sound endoscopic supraglottic laryngectomy. Several authors, including Zeitels, Ambrosch and, particularly, Steiner, demonstrated good functional and oncologic results with a progression from early epiglottic to advanced lesions with cartilage destruction. Data regarding the oncologic success of endoscopic supraglottic laryngectomy appear to compare well with open techniques, Expert Rev. Med. Devices 6(6), (2009)
Transoral laser microsurgery: applications in head & neck oncology
although studies are limited by smaller sample sizes. Reports of results of TLM supraglottic laryngectomy consistently demonstrate earlier and more efficient recovering of swallowing function, with lower rates of secondary total laryngectomy [13] . It should be remembered that the neck remains an important site of failure in supraglottic cancer and should be addressed surgically as a staging procedure when utilizing TLM-based techniques to treat the primary. Oropharyngeal cancer
Transoral microsurgical resection of tongue base carcinomas offers significant advantages over open surgical approaches. Specifically, tumors can be endoscopically resected with significantly less morbidity, obviating the need for transpharyngeal, transmandibular or lip-splitting approaches. The first large series of TLM-based resection of tongue base carcinomas was reported by Steiner in 2003. Subsequent studies from several authors have consistently reported good oncologic and functional outcomes in patients treated with primary TLM tongue base resection, often with neck dissection and the selected use of adjuvant therapy. Use of the operating microscope in TLM excision of these tumors provided for a tailored resection with careful visualization to the tumor–normal tongue interface [14] .
“...studies from several authors have consistently reported good oncologic and functional outcomes in patients treated with primary transoral laser microsurgery tongue base resection, often with neck dissection and the selected use of adjuvant therapy.” Functional and oncologic outcomes for patients treated with TLM tongue base resection disease-specific survival compare favorably with nonsurgical (chemoradiation) treatment protocols. Swallowing function and the requirement for permanent gastrostomy tube feeding is less than observed in patients treated nonsurgically [15–17] . Complications, including potentially life-threatening hemorrhage, are rare [18] .
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series of advanced-stage hypopharyngeal malignancies treated with combinations of chemoradiation therapy. The rate of salvage total laryngectomy was a remarkable 2%, with a 4% incidence of permanent gastronomy tube and 4% incidence of tracheotomy [19] . Similar studies for hypopharyngeal carcinoma from other institutions have also been reported [20] . Summary
Transoral laser microsurgery is a minimally invasive, oncologically sound approach for selected patients with malignant tumors of the head and neck. These techniques allow tailored radical resection with maximum potential for function organ preservation for both primary and recurrent tumors [21,22] . The combination of resection of the primary tumor with neck dissection provides ample pathological material for molecular analysis and risk stratification for delivery of appropriate adjuvant therapy. The use of TLM can be used concurrently with neck dissection and does not limit the application of any adjuvant strategy (radiotherapy or chemoradiotherapy) [16,23] . Multiple organ-sparing TLM procedures are possible without a negative effect on overall survival [24] . The transoral approach obviates the need for pharyngotomy and, therefore, significantly reduces the likelihood of wound contamination by saliva and, subsequently, reduces the probability of wound infection or fistula.
“Multiple organ-sparing transoral laser microsurgery procedures are possible without a negative effect on overall survival.” Using TLM, radical oncologic resection has been accomplished in a variety of anatomic sites with good preservation of function without sacrificing survival. Rates of distant metastasis in patients treated with TLM are similar to those treated by open surgery. The appearance of distant metastasis in patients treated with TLM appears to be related to the site of the primary tumor, presence of nodal metastases and the status of the resection margins of the primary [25] . Financial & competing interests disclosure
Hypopharyngeal cancer
The first large mature series for TLM-resected hypopharyngeal cancers has only recently been reported by Steiner. These authors used aggressive TLM resections with postoperative radiation therapy in a series of patients with pyriform sinus carcinomas. Oncologic results are similar to those reported for comparable References 1
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The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.
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Expert Rev. Med. Devices 6(6), (2009)
