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Original Article |

Vocal Outcomes After Laser Resection of Early-Stage Glottic Cancer With Adjuvant Cryotherapy FREE

P. Daniel Knott, MD; Claudio F. Milstein, PhD; Douglas M. Hicks, PhD; Tom I. Abelson, MD; Michael C. Byrd, MD; Marshall Strome, MD, MS
[+] Author Affiliations

Author Affiliations: Head and Neck Institute (Drs Knott, Abelson, Byrd, and Strome) and Voice Center (Drs Milstein and Hicks), The Cleveland Clinic Foundation, Cleveland, Ohio.


Arch Otolaryngol Head Neck Surg. 2006;132(11):1226-1230. doi:10.1001/archotol.132.11.1226.
Text Size: A A A
Published online

Objective  To evaluate the vocal outcomes of patients with early-stage glottic carcinoma undergoing laser resection with adjuvant cryoablative therapy.

Design  Retrospective review.

Setting  Tertiary care center.

Patients  Twenty patients with early-stage glottic carcinoma.

Intervention  Treatment of early-stage glottic carcinoma with endoscopic carbon dioxide laser resection in conjunction with cryoablation.

Main Outcome Measures  Disease-free survival and subjective and objective measures of posttreatment voice quality, based on serial videolaryngostroboscopy.

Results  There was 1 local treatment failure, with an overall mean disease-free follow-up of 32.6 months (range, 3-93 months). Carbon dioxide laser resection and cryoablative therapy were associated with a significant improvement in subjective voice quality (P<.001). Long-term dysphonia was uniformly improved vis-à-vis the pretreatment condition, even among patients with the most advanced disease undergoing the widest resections. Posttreatment web formation was not noted among 4 patients with anterior commissure involvement.

Conclusions  Endoscopic laser laryngeal surgery performed in conjunction with cryotherapy for early-stage glottic carcinoma yielded excellent primary site control, while improving subjective and objective measures of voice quality. Combined laser surgery and cryotherapy is a possible alternative to radiotherapy for selected patients with early-stage glottic carcinoma who desire curative therapy, while optimizing vocal outcomes.

Figures in this Article

The treatment of early-stage glottic carcinoma has evolved over the past several decades. External beam radiotherapy is the standard treatment, which usually maintains laryngeal form and function, has a high rate of locoregional treatment success, and indirectly treats other regional premalignant mucosal lesions. However, significant morbidity is associated with this treatment modality, with complication rates ranging from 10% to 45%.1 Nevertheless, this organ-sparing approach is commonly associated with excellent posttreatment voice quality.2

Laser surgery, another treatment option, avoids many of these morbidities. It limits treatment to the tissues undergoing malignant change, avoids the morbidity of radiation transit through the neck, is cost-effective, and affords excellent tumor surveillance.37 In addition, laser therapy offers long-term oncologic control and vocal results that are almost equivalent to those associated with external beam radiation. However, a recent study8 concluded that postendoscopic surgery voice quality is poor when the plane of dissection disrupts the vocal ligament and includes part or all of the vocalis muscle.

Excellent long-term posttreatment vocal outcomes were anecdotally noted in a cohort of patients with early-stage glottic carcinoma undergoing combined laser surgery with adjuvant cryotherapy at the Head and Neck Institute, The Cleveland Clinic Foundation, Cleveland, Ohio. Therefore, the present study was undertaken to evaluate the vocal outcomes of patients undergoing this combined treatment. Oncologic outcomes were also investigated to assess the potential for the addition of cryotherapy to aid in the long-term control of primary or recurrent glottic carcinoma.

A retrospective medical record review identified 20 patients with biopsy-proven primary or recurrent glottic squamous cell carcinoma who underwent treatment with combined endoscopic laser surgery and cryoablation from April 1, 1997, to April 1, 2004, at the Head and Neck Institute. One of us (M.S.) treated all 20 patients using a carbon dioxide laser with 5 W of continuous or superpulsed energy in a narrow-beam configuration. Cryotherapy was provided with a laryngeal probe (Frigitronics; CooperSurgical, Inc, Trumbull, Conn) to a maximum temperature of −40°C in 3-mm overlapping applications covering the entire tumor bed. Frozen-section margin analysis was performed on all patients before initiating cryotherapy. No patients were brought back to the operating room for close or positive margins on permanent-section analysis.

We recorded the following patient data: sex, tumor stage and grade, extent of the resection, postoperative complications, rate of locoregional recurrence and distant metastasis, and duration of postoperative follow-up. We also made special note of patients who had received pretreatment with external beam radiotherapy and patients whose glottic cancer involved the anterior commissure. The extent of the resection was graded according to the criteria of the European Laryngological Society Working Committee (ELSWC)9 (Table 1). Disease-free survival was assessed based on scheduled follow-up examinations, including fiberoptic laryngoscopy and videostroboscopy and biannual chest radiographs.

Table Graphic Jump LocationTable 1. Classification of Endoscopic Cordectomies Proposed by the European Laryngological Society Working Committee

Before undergoing surgical treatment, all patients' conditions were comprehensively evaluated and the results were presented at a multidisciplinary tumor board that included head and neck surgeons, a radiation oncologist, and a medical oncologist. Patients were informed of the risks and benefits of combined endoscopic laser laryngeal surgery and cryotherapy and were informed of treatment alternatives.

At data collection, patients were contacted by a third party and were asked to retrospectively analyze their preoperative and postoperative voice quality using a 10-point scale, with 1 representing the poorest possible voice and 10 representing the best possible voice. Patients were also asked to compare their current voice quality with their preoperative condition using a 5-point scale, with 1 representing much worse; 2, somewhat worse; 3, about the same; 4, somewhat better; and 5, much better. A 2-tailed t test was used to determine whether the difference was statistically significant (P<.05).

Patients did not receive speech reeducation. Preoperative and serial postoperative videostroboscopy was performed and recorded with each patient. Nagashima analog (Nagashima, Tokyo, Japan) and Kay (Pentax Medical Company, Montvale, NJ) digital machines were used to record data. Three blinded voice professionals (C.F.M., D.M.H., and T.I.A.) evaluated each videostroboscopic encounter. Because most of the patients had multiple videostroboscopic recordings, the encounters were divided into 3 temporal categories: preoperative assessment, first postoperative assessment (1-2 months after surgery), and final postoperative assessment (3-93 months after surgery). Although the professionals were blinded to the patients' identities and treatment course, the randomized videostroboscopic encounters for each patient were reviewed as a collection to minimize interpatient variability. Reviewers assessed each encounter according to a 100-point dysphonia scale, with 100 representing the worst possible vocal outcome and 1 representing a normal voice. Descriptive statistics were recorded and analyzed comparing the mean dysphonia with the extent of resection, tumor grade, involvement of the anterior commissure, and prior exposure to radiotherapy.

Table 2 gives the patient data and tumor grade and histologic findings. The overall mean disease-free follow-up was 32.6 months (range, 3-93 months). There was 1 local treatment failure, which was salvaged by a revision endoscopic laser cordectomy with cryoablation; this patient is disease free. A second patient who had chosen not to continue returned to the clinic with a second primary glottic mass with lung metastases more than 7 years following successful combined treatment for a poorly differentiated T1b tumor. Three of 20 patients had undergone external beam radiotherapy with curative intent at outside institutions before enrollment in the present study.

Table Graphic Jump LocationTable 2. Patient Characteristics, Histopathologic Classification, and Tumor Grade*

The median ± SD self-reported preoperative voice quality was 4.00 ± 1.94 on a 10-point scale, whereas the self-reported postoperative voice quality was 8.00 ± 2.42 on a 10-point scale. Of 20 patients, 17 (85%) described their voices as somewhat or much improved, while only 1 patient described his voice as somewhat worse following combined laser surgery and cryotherapy. Carbon dioxide laser resection and cryoablative therapy were associated with a significant improvement in subjective voice quality (P<.001).

A comparison of pretreatment dysphonia with early postoperative and long-term posttreatment dysphonia was performed according to the ELSWC criteria (Figure 1). Compared with the pretreatment condition, patients undergoing a type 1 resection, which is limited to the superficial layer of the lamina propria, experienced a mean improvement in voice quality of 12.8% (pretreatment mean dysphonia score of 39 vs posttreatment mean dysphonia score of 34) in the early postoperative period, which was followed by a 46.2% (pretreatment score of 39 vs posttreatment score of 21) mean improvement in the long term. The mean dysphonia among patients undergoing a type 2 resection, which is limited to the superficial aspect of the vocalis muscle, demonstrated an initial improvement of 10.3% (32 vs 29) in the early postoperative period, increasing to 44.8% (29 vs 16) in the final evaluation. When the resection included the medial portion of the vocalis muscle (ELSWC type 3), the initial voice quality was essentially unchanged (43 vs 42) but demonstrated a long-term improvement of 30.3% (43 vs 30). When the surgical resection included the inner perichondrium of the thyroid lamina (ELSWC type 4), the mean early dysphonia demonstrated a marginal deterioration of 2.7% (72 vs 74), but in the long-term the dysphonia improved by 55.6% (72 vs 32).

Place holder to copy figure label and caption
Figure 1.

The mean dysphonia scores for patients classified according to the European Laryngological Society Working Committee resection type. See Table 1 for a detailed explanation of the classifications.

Graphic Jump Location

An analysis of voice quality by tumor stage (carcinoma in situ, T1a, T1b, and T2) was also performed (Figure 2). Patients with carcinoma in situ experienced a minimal improvement of 7.5% (pretreatment mean dysphonia score of 36 vs posttreatment mean dysphonia score of 33.3) in the immediate postoperative period. The mean dysphonia in this group improved by 39.8% (36 vs 21.6) in the long term. Among patients with stage T1a malignancies, the mean dysphonia initially improved by 18.7% (40.7 vs 33.1), with patients experiencing a 53% (40.7 vs 19.1) improvement by the final evaluation. Patients with stage T1b glottic carcinoma experienced a deterioration in their mean dysphonia score of 12.1% (33 vs 37) during the early postoperative period, while over the long term these patients experienced an improvement of 42.4% (33 vs 19). The mean dysphonia among patients with stage T2 disease demonstrated an initial 61.1% (36 vs 58) deterioration, but voice quality improved by 13.9% (36 vs 31) in the long term.

Place holder to copy figure label and caption
Figure 2.

The mean dysphonia scores for patients classified according to tumor stage. Tis indicates carcinoma in situ. See Table 1 for a detailed explanation of the classifications.

Graphic Jump Location

When the anterior commissure was involved in the tumor resection, early voice quality was essentially unchanged (pretreatment mean dysphonia score of 51 vs posttreatment mean dysphonia score of 50), but in the long term the mean dysphonia scores among these patients improved by 43.2% (51 vs 29). No patients with anterior commissure involvement were noted to develop posttreatment anterior glottic webs. Among 3 patients whose disease failed to respond to initial treatment with radiotherapy, the early mean dysphonia was unchanged compared with pretreatment values (33 vs 33), but the mean dysphonia improved by 30.3% (33 vs 23) over the long term.

Vocal outcomes following treatment of early-stage glottic carcinoma have been well studied.1014 Although endoscopic surgery has been established as an oncologically sound treatment alternative compared with external beam radiotherapy, the data regarding speech quality offered by these organ-preserving strategies are mixed.1518 Scarring and tissue fibrosis adjacent to the laser ablation crater have been attributed to decreased mucosal wave formation.1921 Nevertheless, the development of newer generations of lasers with lower power settings, narrower beam sizes, and superpulse features allowing for greater thermal relaxation time have limited this damage.

Despite these improvements, endoscopic laser therapy has not been found to offer significant improvement in posttreatment voice quality. Although 1 study22 demonstrated improvements in such measures as jitter, shimmer, fundamental frequency, and mean phonation time compared with control groups undergoing radiotherapy, other studies1518 have demonstrated equivalent outcomes or worse speech outcomes compared with radiotherapy. Although a true meta-analysis is lacking, it seems as if endoscopic laser surgery is, at best, associated with speech outcomes that are marginally worse than the vocal results associated with external beam radiation.

One of us (M.S.) introduced cryotherapy as adjuvant treatment in patients undergoing laser resections of early glottic cancer with the assumption that the addition of cryotherapy would fundamentally alter the remodeling phase of wound healing. By causing local vascular infarction, cryotherapy may reduce the influx of inflammatory cells into the ablation crater. Furthermore, the necrotic postcryoablated tissue may act as a biologic membrane over the resection margin, potentially enhancing tissue healing. This effect may explain the lack of anterior glottic web formation in any of our patients, even in those with anterior commissure involvement.

In this study, the use of combined laser laryngeal surgery and endoscopic cryotherapy seems to be associated with improvements in subjective voice quality. Other studies16,17,23 have used subjective measures of voice quality and reported positive and negative results. Nevertheless, among this cohort of 20 patients, a low P value was obtained (P<.001), indicating that this effect is unlikely to be due to random chance.

Most important, vocal outcomes were objectively evaluated by 3 blinded voice professionals using the dysphonia index. This 100-point continuous data scale is the most clinically relevant outcome measure for postoperative voice quality. Irrespective of the extent of tumor resection, patients in our study experienced long-term improvement in dysphonia, with the patients undergoing ELSWC type 1 and 2 resections experiencing final voice quality within 20% of normal (Figure 1). Even patients undergoing resections that included the entire vocalis muscle (ELSWC type 3) and the perichondrium of the inner thyroid lamina (ELSWC type 4) had long-term improvements in voice quality, with final voice quality within approximately 30% of normal. Similar results were obtained when vocal outcomes were analyzed according to tumor stage. T2 tumors were associated with an early deterioration in voice quality, followed by substantial improvements in voice quality over the long term. Several patients undergoing ELSWC type 3 resections demonstrated a return of mucosal pliability and wave propagation. These results differ from those of previous techniques in which voice quality deteriorates when the depth of the resection margin includes the vocalis muscle.

We also analyzed the vocal outcomes among the patients who failed initial radiotherapy and among the patients whose tumors involved the anterior commissure. Our results agree with previous findings that these patient groups experience substantial long-term improvements in their mean dysphonia.24

Cryotherapy is a well-studied technology that has been used routinely to treat various benign tumors of the skin and to control various malignant processes. Although cryotherapy has been used for several decades, its use in human glottic carcinoma has not been thoroughly investigated.25,26 Initial enthusiasm with its use as monotherapy in the 1970s waned because of technical flaws and unacceptable rates of recurrence. When used as adjunctive therapy, cryosurgery theoretically provides additional margin control. Tissue necrosis is achieved when the temperature is rapidly reduced below −30°C, causing intracellular crystallization of water, denaturation of proteins, and accumulation of toxic electrolyte concentrations.27 These changes cause local cellular necrosis, while preferentially permitting some of the extracellular matrix protein to survive.

The combined use of cryosurgery and endoscopic laser laryngeal surgery can potentially improve oncologic outcomes without compromising postoperative voice quality. Precise intraoperative margin control may be difficult to achieve with the use of frozen-section analysis of laser-ablated tissue. Thermal damage to the tissue samples and coarctation of the specimen edge during specimen preparation may lead to false-positive and false-negative results on histopathologic evaluation. The use of adjuvant cryosurgery offers several millimeters of tissue necrosis when used in an overlapping fashion. This additional margin may represent an important benefit when considering complete tumor eradication in the complex 3-dimensional anatomy of the human larynx. Only 1 patient in our study experienced recurrent glottic carcinoma during follow-up. Salvage treatment, which consisted of a second combined endoscopic procedure, was successful. Furthermore, an additional 2 patients had close margins on permanent-section analysis, but they have not developed recurrences on laryngovideostroboscopic and subsequent intraoperative suspension microlaryngeal follow-up. Therefore, the use of cryotherapy may prevent a return to the operating room for additional resections for patients with close margins on permanent sections, which is commonly documented in the endoscopic laryngeal cancer literature.

Our study has several limitations. The lack of a control group prevented us from comparing outcomes between combined endoscopic laser and cryosurgery with those of a more accepted treatment modality. As with any retrospective analysis, the patients' assessment of pretreatment and posttreatment voice quality is subject to recall bias. Furthermore, the limited number of patients restricted our analysis to descriptive statistics. Nevertheless, the surprisingly good vocal results obtained using combined therapy warranted a preliminary investigation.

Endoscopic laser laryngeal surgery performed in conjunction with cryotherapy of early-stage glottic carcinoma yielded excellent primary site and locoregional control while significantly improving subjective voice quality. Analysis of videostroboscopy data demonstrated that, although deeper resection margins were associated with worse vocal outcomes, ELSWC type 3 and type 4 resections were associated with substantial improvements in voice quality compared with the pretreatment condition. We believe that combined laser surgery and cryotherapy is a possible alternative to radiotherapy for selected patients with early-stage glottic carcinoma who desire curative therapy, with improved vocal outcomes. Based on our preliminary results, the process of glottic wound healing and tissue remodeling following laser surgery and cryoablation should be thoroughly investigated.

Correspondence: Marshall Strome, MD, MS, Head and Neck Institute, The Cleveland Clinic Foundation, Floor A-71, 9500 Euclid Ave, Cleveland, OH 44195.

Submitted for Publication: October 11, 2005; final revision received May 21, 2006; accepted June 4, 2006.

Author Contributions: All authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Knott, Milstein, and Strome. Acquisition of data: Knott, Milstein, Hicks, and Byrd. Analysis and interpretation of data: Knott, Milstein, Hicks, Abelson, and Strome. Drafting of the manuscript: Knott and Strome. Critical revision of the manuscript for important intellectual content: Knott, Milstein, Hicks, Abelson, Byrd, and Strome. Statistical analysis: Hicks. Obtained funding: Knott. Administrative, technical, and material support: Milstein, Hicks, and Byrd. Study supervision: Knott and Strome.

Financial Disclosure: None reported.

Jorgensen  KGodballe  CHansen  OBastholt  L Cancer of the larynx: treatment results after primary radiotherapy with salvage surgery in a series of 1005 patients. Acta Oncol 2002;4169- 76
PubMed Link to Article
Rosier  JFGregoire  VCounoy  H  et al.  Comparison of external radiotherapy, laser microsurgery and partial laryngectomy for the treatment of T1N0M0 glottic carcinomas: a retrospective evaluation. Radiother Oncol 1998;48175- 183
PubMed Link to Article
Damm  MSittel  CStreppel  M  et al.  Transoral CO2 laser for surgical management of glottic carcinoma in situ. Laryngoscope 2000;1101215- 1221
PubMed Link to Article
Eckel  HEThumfart  WJungehulsing  M  et al.  Transoral laser surgery for early glottic carcinoma. Eur Arch Otorhinolaryngol 2000;257221- 226
PubMed Link to Article
Luscher  MSPedersen  UJohansen  LV Treatment outcome after laser excision of early glottic squamous cell carcinoma: a literature survey. Acta Oncol 2001;40796- 800
PubMed Link to Article
Steiner  W Results of curative laser microsurgery of laryngeal carcinomas. Am J Otolaryngol 1993;14116- 121
PubMed Link to Article
Brandenburg  JH Laser cordotomy versus radiotherapy: an objective cost analysis. Ann Otol Rhinol Laryngol 2001;110312- 318
PubMed
Peretti  GPiazza  CBalzanelli  CMensi  MCRossini  MAntonelli  AR Preoperative and postoperative voice in Tis-T1 glottic cancer treated by endoscopic cordectomy: an additional issue for patient counseling. Ann Oto Rhino Laryngol 2003;112759- 763
PubMed
Remacle  MEckel  HEAntonelli  A  et al.  Endoscopic cordectomy: a proposal for a classification by the Working Committee, European Laryngological Society. Eur Arch Otorhinolaryngol 2000;257227- 231
PubMed Link to Article
Mendenhall  WMWerning  JWHinerman  RWAmdur  RJVillaret  DB Management of T1-T2 glottic carcinomas. Cancer 2004;1001786- 1792
PubMed Link to Article
Davis  RK Endoscopic surgical management of glottic laryngeal cancer. Otolaryngol Clin North Am 1997;3079- 86
PubMed
Davis  RKKriskovich  MDBuntin  CS  et al.  Endoscopic supraglottic laryngectomy with postoperative irradiation. Ann Otol Rhinol Laryngol 2004;113132- 138
PubMed
Moreau  PR Treatment of laryngeal carcinomas by laser endoscopic microsurgery. Laryngoscope 2000;1101000- 1006
PubMed Link to Article
Shvero  JKoren  RZohar  L  et al.  Laser surgery for the treatment of glottic carcinomas. Am J Otolaryngol 2003;2428- 33
PubMed Link to Article
Tamura  EKitahara  SOgura  M  et al.  Voice quality after laser surgery or radiotherapy for T1a glottic carcinoma. Laryngoscope 2003;113910- 914
PubMed Link to Article
Rydell  RSchalen  LFex  S  et al.  Voice evaluation before and after laser excision vs. radiotherapy of T1A glottic carcinoma. Acta Otolaryngol 1995;115560- 565
PubMed Link to Article
McGuirt  WFBlalock  DKoufman  JA  et al.  Comparative voice results after laser resection or irradiation of T1 vocal cord carcinoma. Arch Otolaryngol Head Neck Surg 1994;120951- 955
PubMed Link to Article
Sittel  CEckel  HEEschenburg  C Phonatory results after laser surgery for glottic carcinoma. Otolaryngol Head Neck Surg 1998;119418- 424
PubMed Link to Article
Sullivan  CARader  AAbdul-Karim  FWAbbass  HMohr  RM Dose-related tissue effects of the CO2 and noncontact Nd:YAG lasers in the canine glottis. Laryngoscope 1998;1081284- 1290
PubMed Link to Article
Garrett  CGReinisch  L New-generation pulsed carbon dioxide laser: comparative effects on vocal fold wound healing. Ann Otol Rhinol Laryngol 2002;111471- 476
PubMed
Garcia-Tapia  LRPardo  LJMarigil  M  et al Effects of laser upon Reinke's space and the neural system of the vocalis muscle.  In: Lawrence  VL, ed. Transcripts of the Twelfth Symposium: Care of the Professional Voice. New York, NY: Voice Foundation; 1984:289-291
Jepsen  MCGurushanthaiah  DRoy  N  et al.  Voice, speech, and swallowing outcomes in laser-treated laryngeal cancer. Laryngoscope 2003;113923- 928
PubMed Link to Article
Delsupehe  KGZink  ILejaegere  MBastian  RW Voice quality after narrow-margin laser cordectomy compared with laryngeal irradiation. Otolaryngol Head Neck Surg 1999;121528- 533
PubMed Link to Article
Pearson  BWSalassa  JR Transoral laser microresection for cancer of the larynx involving the anterior commissure. Laryngoscope 2003;1131104- 1112
PubMed Link to Article
Strome  M Cryosurgery: the effect on the canine endolaryngeal structures. Laryngoscope 1971;811057- 1065
PubMed Link to Article
Hong  SWSilverstein  HSadeghee  S The effect of cryosurgery on the canine and human larynx. Laryngoscope 1977;871079- 1085
PubMed Link to Article
Mulvaney  TJMiller  D Endolaryngeal cryosurgery: an improved technique. Arch Otolaryngol 1976;102226- 229
PubMed Link to Article

Figures

Place holder to copy figure label and caption
Figure 1.

The mean dysphonia scores for patients classified according to the European Laryngological Society Working Committee resection type. See Table 1 for a detailed explanation of the classifications.

Graphic Jump Location
Place holder to copy figure label and caption
Figure 2.

The mean dysphonia scores for patients classified according to tumor stage. Tis indicates carcinoma in situ. See Table 1 for a detailed explanation of the classifications.

Graphic Jump Location

Tables

Table Graphic Jump LocationTable 1. Classification of Endoscopic Cordectomies Proposed by the European Laryngological Society Working Committee
Table Graphic Jump LocationTable 2. Patient Characteristics, Histopathologic Classification, and Tumor Grade*

References

Jorgensen  KGodballe  CHansen  OBastholt  L Cancer of the larynx: treatment results after primary radiotherapy with salvage surgery in a series of 1005 patients. Acta Oncol 2002;4169- 76
PubMed Link to Article
Rosier  JFGregoire  VCounoy  H  et al.  Comparison of external radiotherapy, laser microsurgery and partial laryngectomy for the treatment of T1N0M0 glottic carcinomas: a retrospective evaluation. Radiother Oncol 1998;48175- 183
PubMed Link to Article
Damm  MSittel  CStreppel  M  et al.  Transoral CO2 laser for surgical management of glottic carcinoma in situ. Laryngoscope 2000;1101215- 1221
PubMed Link to Article
Eckel  HEThumfart  WJungehulsing  M  et al.  Transoral laser surgery for early glottic carcinoma. Eur Arch Otorhinolaryngol 2000;257221- 226
PubMed Link to Article
Luscher  MSPedersen  UJohansen  LV Treatment outcome after laser excision of early glottic squamous cell carcinoma: a literature survey. Acta Oncol 2001;40796- 800
PubMed Link to Article
Steiner  W Results of curative laser microsurgery of laryngeal carcinomas. Am J Otolaryngol 1993;14116- 121
PubMed Link to Article
Brandenburg  JH Laser cordotomy versus radiotherapy: an objective cost analysis. Ann Otol Rhinol Laryngol 2001;110312- 318
PubMed
Peretti  GPiazza  CBalzanelli  CMensi  MCRossini  MAntonelli  AR Preoperative and postoperative voice in Tis-T1 glottic cancer treated by endoscopic cordectomy: an additional issue for patient counseling. Ann Oto Rhino Laryngol 2003;112759- 763
PubMed
Remacle  MEckel  HEAntonelli  A  et al.  Endoscopic cordectomy: a proposal for a classification by the Working Committee, European Laryngological Society. Eur Arch Otorhinolaryngol 2000;257227- 231
PubMed Link to Article
Mendenhall  WMWerning  JWHinerman  RWAmdur  RJVillaret  DB Management of T1-T2 glottic carcinomas. Cancer 2004;1001786- 1792
PubMed Link to Article
Davis  RK Endoscopic surgical management of glottic laryngeal cancer. Otolaryngol Clin North Am 1997;3079- 86
PubMed
Davis  RKKriskovich  MDBuntin  CS  et al.  Endoscopic supraglottic laryngectomy with postoperative irradiation. Ann Otol Rhinol Laryngol 2004;113132- 138
PubMed
Moreau  PR Treatment of laryngeal carcinomas by laser endoscopic microsurgery. Laryngoscope 2000;1101000- 1006
PubMed Link to Article
Shvero  JKoren  RZohar  L  et al.  Laser surgery for the treatment of glottic carcinomas. Am J Otolaryngol 2003;2428- 33
PubMed Link to Article
Tamura  EKitahara  SOgura  M  et al.  Voice quality after laser surgery or radiotherapy for T1a glottic carcinoma. Laryngoscope 2003;113910- 914
PubMed Link to Article
Rydell  RSchalen  LFex  S  et al.  Voice evaluation before and after laser excision vs. radiotherapy of T1A glottic carcinoma. Acta Otolaryngol 1995;115560- 565
PubMed Link to Article
McGuirt  WFBlalock  DKoufman  JA  et al.  Comparative voice results after laser resection or irradiation of T1 vocal cord carcinoma. Arch Otolaryngol Head Neck Surg 1994;120951- 955
PubMed Link to Article
Sittel  CEckel  HEEschenburg  C Phonatory results after laser surgery for glottic carcinoma. Otolaryngol Head Neck Surg 1998;119418- 424
PubMed Link to Article
Sullivan  CARader  AAbdul-Karim  FWAbbass  HMohr  RM Dose-related tissue effects of the CO2 and noncontact Nd:YAG lasers in the canine glottis. Laryngoscope 1998;1081284- 1290
PubMed Link to Article
Garrett  CGReinisch  L New-generation pulsed carbon dioxide laser: comparative effects on vocal fold wound healing. Ann Otol Rhinol Laryngol 2002;111471- 476
PubMed
Garcia-Tapia  LRPardo  LJMarigil  M  et al Effects of laser upon Reinke's space and the neural system of the vocalis muscle.  In: Lawrence  VL, ed. Transcripts of the Twelfth Symposium: Care of the Professional Voice. New York, NY: Voice Foundation; 1984:289-291
Jepsen  MCGurushanthaiah  DRoy  N  et al.  Voice, speech, and swallowing outcomes in laser-treated laryngeal cancer. Laryngoscope 2003;113923- 928
PubMed Link to Article
Delsupehe  KGZink  ILejaegere  MBastian  RW Voice quality after narrow-margin laser cordectomy compared with laryngeal irradiation. Otolaryngol Head Neck Surg 1999;121528- 533
PubMed Link to Article
Pearson  BWSalassa  JR Transoral laser microresection for cancer of the larynx involving the anterior commissure. Laryngoscope 2003;1131104- 1112
PubMed Link to Article
Strome  M Cryosurgery: the effect on the canine endolaryngeal structures. Laryngoscope 1971;811057- 1065
PubMed Link to Article
Hong  SWSilverstein  HSadeghee  S The effect of cryosurgery on the canine and human larynx. Laryngoscope 1977;871079- 1085
PubMed Link to Article
Mulvaney  TJMiller  D Endolaryngeal cryosurgery: an improved technique. Arch Otolaryngol 1976;102226- 229
PubMed Link to Article

Correspondence

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