KTP Laser Treatment of Early Glottic Cancer: A Multi-Institutional Retrospective Study

Use of the 445-nm Blue Laser for Management of Early Glottic Carcinoma: Preliminary 1-Year Results

OBJECTIVE

To analyze oncological efficacy and voice outcomes of the 445-nm blue laser (BL) in the treatment of early glottic carcinoma and compare results with the 532-nm potassium-titanyl-phosphate (KTP) laser.

STUDY DESIGN

Single institution, retrospective chart review.

METHODS

All patients who underwent microlaryngoscopic KTP or BL laser excision of early glottic carcinoma from 2018 to the present day with at least 1-year follow-up were included. Primary and recurrent disease, including radiation and surgical failures, were included. Demographic data, voice outcomes and oncologic outcomes were compared between the two laser groups.

RESULTS

Forty-nine patients met the inclusion criteria for the BL group and 88 for the KTP group, with average follow-up of 635 and 1236 days, respectively. Oncologic outcomes were not significantly different, with disease-specific survival rates of 95.9% for BL and 100% for KTP (p = 0.13), organ preservation rates of 98.0% for BL and 95.6% for KTP (p = 0.39), and local control rates of 93.9% for BL and 92.1% for KTP (p = 0.81). Both BL and KTP groups showed significant improvement in CAPE-V (p = 0.04, 0.006 respectively) and VHI-10 scores (p = 0.003, <0.00001) following surgery.

CONCLUSIONS

Photoangiolytic removal of early glottic carcinoma with BL appears to be equally safe and effective as with KTP laser at minimum one-year follow-up, and with excellent voice outcomes. Additional study will be warranted over time to assess long-term outcomes in BL patients.

LEVEL OF EVIDENCE

3 Laryngoscope, 2024.

Awake endoscopic laser surgery for early glottic carcinoma

The objective of this study was to demonstrate the oncologic efficacy of awake endoscopic laryngeal surgery in the treatment of T1-T2 glottic carcinoma. This is a retrospective study. Seventy-one patients with early glottic carcinoma (T1a- 26, T1b- 18, T2- 27) who underwent awake flexible endoscopic laryngeal surgery under local anesthesia and mild intravenous sedation were included in the study. In 64 cases (90.1%) only endoscopic tumor ablation by Nd:YAG laser (in 32.4% of cases being preceded by diathermy snare excision) was performed, and in 7 T2 cases postoperative radiotherapy was also offered. There were no complications during or after the endoscopic surgery. Ultimate control of disease, including salvage treatment, was obtained in 67 patients (94.4%). Cure without recurrence was achieved in 60 cases (84.5%). Local control without salvage radiotherapy or/and open surgery was achieved in 64 (90.1%) patients. Larynx preservation was obtained in 66 (93.0%) cases. At 5 years from the beginning of endoscopic treatment, 74.6% of the patients were alive and free of disease. The best results were obtained in the T1a group of treated patients, all the patients being free of disease with the preserved larynx. Awake endoscopic laryngeal surgery is a safe and oncologically efficient method of treatment of early glottic carcinoma that can be considered as an alternative to the traditional approach, primarily, for patients with risks/contraindications for radiotherapy, general anesthesia, and transoral microsurgery, and also for the patients who prefer to avoid general anesthesia with its related risks and would rather choose office-based laryngeal surgery.

Surgical Treatment of Early Glottic Cancer

The incidence of all head and neck malignancies is rising worldwide, with carcinoma of the larynx constituting approximately 1% of all cancers. Early glottic cancer responds quite favorably to surgical intervention due to its early presentation, coupled with the low rate of regional and distant metastases. This article focuses on various approaches to the surgical treatment of early glottic cancer. Details include the clinical and radiological evaluation of laryngeal cancer, the goals of treatment, current surgical options for early disease, approach to surgical resection margins and management of nodal disease, and complications associated with each treatment modality.

Outcomes of KTP Laser Ablation in Glottic Neoplasms: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the safety and clinical effectiveness of transoral laser microsurgery (TLM) with potassium-titanyl-phosphate (KTP) laser ablation for glottic neoplasms.

DATA SOURCE

MEDLINE via PubMed, SCOPUS, Web of Science, and Cochrane Library.

REVIEW METHODS

A systematic review and meta-analysis of studies assessing the safety and efficacy of KTP laser therapy in patients with early-stage glottic neoplasms.

RESULTS

Eight studies were included. After an average follow-up of 3.3 years, the overall survival and disease-free survival for patients who underwent KTP were 90.7% (95% CI 85%-96.5%) and 98.5% (95% CI 97.3%-99.8%), respectively. In the single-arm meta-analysis, the pooled estimate of recurrence was 7.7% (95% CI 3.4%-12%). The overall voice handicap index (VHI) estimate attributed to KTP in the single-arm meta-analysis was 6.76 (95% CI [3.05, 10.48]) and 5.21 (95% CI [2.86, 7.56]) within 6 months and after a one-year follow-up, respectively.

CONCLUSION

KTP laser ablation is a safe and effective method for treating patients with early glottic neoplasms. Laryngoscope, 2023.

Soft robotic manipulator for intraoperative MRI-guided transoral laser microsurgery

Magnetic resonance (MR) imaging (MRI) provides compelling features for the guidance of interventional procedures, including high-contrast soft tissue imaging, detailed visualization of physiological changes, and thermometry. Laser-based tumor ablation stands to benefit greatly from MRI guidance because 3D resection margins alongside thermal distributions can be evaluated in real time to protect critical structures while ensuring adequate resection margins. However, few studies have investigated the use of projection-based lasers like those for transoral laser microsurgery, potentially because dexterous laser steering is required at the ablation site, raising substantial challenges in the confined MRI bore and its strong magnetic field. Here, we propose an MR-safe soft robotic system for MRI-guided transoral laser microsurgery. Owing to its miniature size (Ø12 × 100 mm), inherent compliance, and five degrees of freedom, the soft robot ensures zero electromagnetic interference with MRI and enables safe and dexterous operation within the confined oral and pharyngeal cavities. The laser manipulator is rapidly fabricated with hybrid soft and hard structures and is powered by microvolume (<0.004 milliter) fluid flow to enable laser steering with enhanced stiffness and lowered hysteresis. A learning-based controller accommodates the inherent nonlinear robot actuation, which was validated with laser path-following tests. Submillimeter laser steering accuracy was demonstrated with a mean error < 0.20 mm. MRI compatibility testing demonstrated zero observable image artifacts during robot operation. Ex vivo tissue ablation and a cadaveric head-and-neck trial were carried out under MRI, where we employed MR thermometry to monitor the tissue ablation margin and thermal diffusion intraoperatively.

Vocal Fold Cyst Formation after Photoangiolytic KTP Laser Treatment of Early Glottic Cancer

OBJECTIVE

The incidence of post-operative glottic cyst (POGC) formation in patients treated with transoral laser microsurgery with potassium-titanyl-phosphate laser (TLM-KTP) photoablation of early glottic carcinoma (EGC) has not previously been described.

METHODS

A retrospective chart review was performed to identify all patients with early glottic cancer who underwent with single-modality TLM-KTP at our institution. Each patient received regular follow up with videostroboscopy for tumor surveillance. New glottic cysts seen on surveillance examinations were noted and their management was documented.

RESULTS

A total of 33 patients met inclusion criteria. Eight patients (24%) developed POGC's within the original geographic perimeter of the cancerous vocal fold(s): 6 in the infraglottic region and 2 near the vocal process, at an average of 8 months after their initial cancer surgery. Of these 8 POGC's, 7 were at the periphery of the original tumor distribution and 1 was in the center of it. No POGC's were associated with any change in voice. Four of the 8 POGC's were phonosurgically excised, all without evidence of malignancy on pathology. The remaining 4 were monitored: 2 were stable for an average of 49 months of follow up; the remaining 2 resolved spontaneously by 7 and 31 months after first identification.

CONCLUSIONS

POGC's are a frequent sequela of TLM-KTP for EGC. While these results suggest that they are unlikely to represent submucosal recurrences, surgeons should have a low threshold to biopsy if there is clinical concern for such and should counsel patients pre-operatively about the potential for their formation.