2018 Section 6 - Laryngology, Voice Disorders, and Bronchoesophalogy

Zeitels and Burns

high-resolution laryngeal stroboscopy 21 or high-speed videolaryngoscopy. 22 Despite decades of surgical innovation that maintained high cure rates with excellent voice outcomes, radiotherapy has been the mainstay of treatment at most institutions. Remarkably, otolaryngologists are the referral source and triage pathway for patients with early glottic cancer to undergo radiotherapy. This is surprising since well-reported oncologically successful endoscopic treatment has been achieved for almost a century by laryngeal surgeons. Therefore, the primary reasons that surgeons refer glottic- cancer patients to radiotherapy would be that they view the endoscopic and/or reconstructive techniques as being too difficult and/or that the voice outcome from endolaryngeal treatment is not comparable to radiotherapy. To further facilitate the technique of endoscopic surgical treatment of early glottic cancer, photoangiolytic 532-nm potassium-titanyl-phosphate (KTP) laser management was introduced in 2008. 23 Prior to this publication, the initial angiolytic laser treatment of early glottic cancer was reported a decade ago at the American Broncho- Esophagological Association. 24 This technique was advanced judiciously over a 5-year period, employing the technically superior 532-nm KTP laser. 25-28 Targeting the neovascularization of glottic tumors capitalized on Folkman’s 29,30 concept of the increased density of angio- genic microcirculation in cancer and Anderson’s concept of selective photothermolysis. 31,32 The 532-nm KTP laser technique is composed of invo- luting the cancer with microsurgically directed angiolytic non-ionizing radiation, thereby embodying valuable ele- ments of precise surgery and zoned radiotherapy to create a unique hybrid approach. The laser energy is concentrated within the dense aberrant angiogenic microcirculation of the tumors 5 while not penetrating deeply into the normal soft tissue of the vocal fold. This minimizes thermal trauma and fibrosis of the extralesional underlying normal glottal soft tissue, thereby minimizing loss of paraglottic muscula- ture and optimizing preservation of normal residual superfi- cial lamina propria necessary for phonatory mucosal pliability and glottal vibration. There are a number of advantages of photoangiolytic KTP laser treatment 23 as compared with cold-instru- ment 12,13,33 and CO 2 laser treatment. 6-9,34,35 Based on the authors’ > 50 year combined experience with endoscopic treatment of laryngeal cancer using cold instruments and electrocautery as well as a variety of lasers (CO 2 , pulsed dye, KTP, and thulium), fiber-based 532 KTP laser pho- toangiolysis has become their preferred approach. Precise tumor removal with the KTP laser is achieved because microsurgical visualization of the cancer and surrounding normal tissue was superior. The enhanced view of the tumor removal and perimeter normal glottic tissue was due to

enhanced hemostasis with minimal carbonized normal tis- sue obscuring the margin. When using the KTP laser, it is reasonably easy to pre- cisely vary the depth of tumor removal while adjusting to the frequent variability of the microscopic depth of inva- sion. This is most clearly encountered when a heteroge- neous early glottic cancer has intraepithelial dysplasia at the perimeter of the region of microinvasion. In addition, the KTP laser can be transmitted tangentially through small glass fibers (.3-.6 mm), unlike a mirror-guided CO 2 laser or the more cumbersome CO 2 laser wave guide. 36 This is espe- cially important while surgically preserving the architec- tural anatomy of the anterior commissure. We have achieved enhanced voice results using photoan- giolytic KTP laser treatment compared to our prior strate- gies 10 to 20 years ago with cold instruments and the CO 2 laser. 15,37 However, despite the fact that oncologic effective- ness using photoangiolytic KTP laser treatment was pub- lished in a pilot series 23 of untreated glottic cancer patients, a larger series has not been reported. In that initial investi- gation, 23 there was a limited number of cases and limited follow-up. Consequently, a more comprehensive review of this approach is necessary to examine oncologic efficacy of KTP laser treatment in a previously untreated glottic-cancer population. Materials and Methods A retrospective investigation was done with institutional review board approval. One hundred seventeen patients underwent suspension microlaryngoscopy with angiolytic 532-nm KTP laser treatment of early glottic cancer (T1 and T2 lesions) with ultra-narrow margins between 2005 and 2010. No patients who presented with T1 or T2 disease were referred for initial radiotherapy. The technique (Figures 1A-1H) has been previously described in detail. 23 These surgical images reflect the fact that the tumor is ablated and not resected en block. A continuous-wave mode is sometimes used to enhance the speed of the procedure for larger and thicker tumors. Cooling is used when employing a continuous-wave mode to debulk larger tumors and thereby mitigate the oven effect, which would injure non- cancerous glottal mucosa at the distal laryngoscope aper- ture. A pulsed mode is used at the interface of the cancer with the normal underlying paraglottic soft tissue so as to maximally preserve it. Those with bilateral disease were treated in a staged fashion to optimally preserve the phonatory architecture of the anterior glottal commissure 23 (Figures 2A and 2B). The timing between the staged procedures was typically 6 to 8 weeks. It was based on the size and location of the tumor, the individual patient’s healing process, the logistics of where he or she lived, and his or her personal schedule.

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