Narrow-Band Imaging in Transoral Laser Surgery for Early Glottic Cancer: A Randomized Controlled Trial

OBJECTIVE

Assessing whether the additional use of narrow-band imaging (NBI) in transoral laser surgery (TOLS) for early laryngeal cancer improves clinical outcomes.

STUDY DESIGN

Randomized controlled trial, performed between September 2015 and November 2022.

SETTING

A tertiary referral hospital in The Netherlands.

METHODS

TOLS was carried out in 113 patients. The procedure was performed with white light imaging (WLI, n = 56) alone, or combined with NBI (n = 57). Patients received frequent follow-up laryngoscopy. Resection margin status, recurrence rate, and recurrence-free survival at 12 months, 18 months, and after study termination (maximum 86 months) were analyzed.

RESULTS

Thirty-one cases in the WLI group had a positive resection margin, versus 16 in the NBI group (p = .002). After 12 months, the recurrence-free survival was 92%: 87% for WLI versus 96% for NBI, p = .07. The recurrence rate was 7/56 (13%) for WLI, versus 2/57 (4%) for NBI, p = .09. After 18 months, the recurrence-free survival was 84% for WLI versus 96% for NBI, p = .02. The recurrence rate was 9/56 (16%) for WLI, versus 2/57 (4%) for NBI, p = .02. After study termination, the recurrence-free survival was 71% for WLI versus 83% for the NBI group (p = .08). The recurrence rate was 16/56 for WLI, versus 10/57 for NBI (p = .16).

CONCLUSION

The additional use of NBI during TOLS significantly decreased the number of positive resection margins. Although not statistically significant at all time points, patients treated with NBI-supported TOLS showed a lower recurrence rate and better recurrence-free survival. Further studies in larger patient groups are needed to confirm these results.

Surgery alone for transorally resected human papillomavirus-driven head and neck cancer-can we de-intensify adjuvant therapy to 0 Gy and 0 mg/m2 ?

LAY SUMMARY

Although smoking has traditionally been the dominant causative factor of head and neck cancer, cancers of the tonsils and base of tongue increasingly are being driven by human papillomavirus, and these cancers are easier to cure. When radiation is used as the primary curative treatment, a number of studies have shown good outcomes with reduced doses of both radiation and chemotherapy. New techniques that access the tumor through the mouth instead of the jaw have made surgery dramatically less toxic. Outcomes are favorable, and many patients traditionally given radiation and chemotherapy afterward may be able to safely omit them.

Efficacy of Transnasal Flexible Videoendoscopy With Narrow Band Imaging for Follow-Up of Patients After Transoral Laser Cordectomy

BACKGROUND AND OBJECTIVES

Transoral laser surgery is the optimal surgical treatment modality for the early stages of glottic cancer. To allow for further treatment to be as effective and as minimal as possible, persistent or recurrent tumors should be detected very soon. The main aim is to minimize the risk of necessity of performing a total laryngectomy. Flexible videoendoscopy with narrow band imaging (NBI) was recommended by the European Laryngological Society as a diagnostic method for the follow-up of patients treated for laryngeal cancer. Nevertheless, the efficacy of this technique has not been extensively studied in patients after transoral laser cordectomies for vocal fold cancer. The aim of this study was to evaluate the efficacy of in-office transnasal NBI flexible videoendoscopy in the follow-up of patients after transoral laser cordectomy for glottic cancer. We also focused on describing the specific characteristics of recurrent tumor appearance.

MATERIALS AND METHODS

The presented study was conceived as a prospective study. Ninety-four consecutive patients who underwent transoral laser cordectomy for severe dysplasia, Tis, T1, and T2 glottic cancer in the period from June 2010 to August 2015 were enrolled in the study. All patients were postoperatively regularly followed using transnasal videoendoscopic examinations with NBI. Whenever a suspect lesion was identified during in-office examination, its nature was proven histologically.

RESULTS

We discovered 23 suspect findings in 21 patients by means of flexible videoendoscopy with NBI. Fifteen (65.2%) of them were histologically confirmed as recurrent tumors, whereas in 8 (34.8%) of them, the recurrent tumor was not proven. In two patients, the recurrent tumor was evident on computed tomography or magnetic resonance imaging, but NBI endoscopy did not reveal relapsing disease. The rest (71 patients) were considered true negative. Of the 15 recurrent tumors detected by NBI-coupled videoendoscopy, 8 (53.3%) were identified as submucosal masses with nonsignificant or no vascular changes, 4 (26.7%) were noted as the progression of leukoplakia without visible vascular changes, only 2 (13.3%) showed typical vascular changes, and, in 1 (6.7%) case, evident, significantly exophytic tumor with pathological vascularization was discovered. The sensitivity, specificity, and positive and negative predictive values of the in-office transnasal videolaryngoscopy with NBI were calculated to be 88%, 92%, 71%, and 97%, respectively.

CONCLUSIONS

The results of the study demonstrate that transnasal endoscopy with NBI in an outpatient setting is an excellent method for the follow-up of patients after transoral laser cordectomy for glottic cancer. The method achieves high sensitivity, specificity, and negative predictive value and a slightly low positive predictive value. Nevertheless, we must bear in mind that recurrent tumors after previous endoscopic resection may have a completely different appearance than new tumors originating from previously untreated tissues. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Carbon debris and fiber cleaving: Effects on potassium-titanyl-phosphate laser energy and chorioallantoic membrane model vessel coagulation

OBJECTIVES/HYPOTHESIS

Photoangiolytic precision afforded by the 532-nm potassium-titanyl-phosphate (KTP) laser relies on predictable energy delivery. Inadequate energy output can cause vessel rupture, and excessive energy can cause thermal damage. The quality of the cleaved surface and carbon deposits from ablated tissue are two factors that could negatively impact fiber performance. The effects of these on energy output and blood vessel coagulation were assessed using a chorioallantoic membrane (CAM) model.

STUDY DESIGN

Comparative analysis.

METHODS

Laser fibers with carbon debris, optimal fiber cleaving, and suboptimal cleaving were inspected at three times magnification, and the light dispersion pattern of each fiber was rated. The average energy output from consecutive pulses through each fiber configuration was recorded. The effect of these fiber conditions on clinical efficacy was estimated by measuring vessel coagulation versus rupture in the CAM model. Repeated measures analysis of variance compared results.

RESULTS

Carbon debris and suboptimal cleaving resulted in decreased energy output in comparison to optimal cleaving ([-Δ244 mJ, d = 4.31, P < .001] and [-Δ195 mJ, d = 6.04, P < .001]). Optimal cleaving resulted in immediate coagulation of vessels. Fibers with suboptimal cleaving and carbon debris had unpredictable outcomes, requiring multiple pulses for coagulation or causing vessel rupture.

CONCLUSIONS

KTP laser fiber function is significantly affected by fiber tip condition. Carbon debris and suboptimal cleaving create significant attenuation of energy, which results in an unpredictable angiolytic effect, as demonstrated by increased vessel rupture in the CAM model. Optimal recleaving of KTP laser fibers restores prior energy output and predictable coagulation. Care should be taken to avoid carbon debris on laser-fiber tips and to cleave fibers properly.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:2244-2248, 2019.

A Comparison of Laser-Protected Endotracheal Tubes

OBJECTIVES

To compare the physical characteristics of 3 laser-protected endotracheal tubes (LPETs) commonly used in endoscopic laser surgery. To report potential intraoperative problems related to LPET use and suggest practical solutions.

STUDY DESIGN

Comparative analysis.

SETTING

Academic laboratory.

SUBJECTS AND METHODS

Physical characteristics of the Mallinckrodt Laser-Flex (MTL), Medtronic Laser-Shield II (ML-II), and Rusch LaserTubus (RL) were compared. The effect of bending LPETs on airflow resistance was estimated with a pressure transducer. The force required to pull each tube through the glottis and the pressure exerted during this maneuver were measured in a fresh cadaveric human larynx.

RESULTS

The design features and physical characteristics of LPETs differ, including varying balloon-tip lengths. Bending LPETs to acute angles caused significant pressure increase within the RL tube (Δ 3.42 cm H₂O) and minimal change within the ML-II (Δ 0.12 cm H₂O) and MTL (Δ 0.21 cm H₂O) tubes. The average force required to pull the RL (48.12 g, P = .003) and MTL (282.4 g, P = .001) tubes through the glottis was 7.6× and 44.5× greater than that for the ML-II (6.39 g). When pulled through the vocal folds, the ML-II cuff exerted no detectable pressure, whereas higher pressures were measured for the RL (2.2 cm H₂O) and MTL (6.5 cm H₂O) tubes.

CONCLUSION

The ML-II tube had the most favorable characteristics, with minimal pressure during extubation and resistance to kinking. The RL tube kinks readily with a resultant increase in resistance to airflow. The MTL tube extends farther into the trachea due to a relatively elongated balloon-tip configuration. Future LPET designs should incorporate features that avoid intraoperative difficulties related to airway protection and ventilation.

Narrow-band imaging in transoral laser surgery for early glottic cancer in relation to clinical outcome

BACKGROUND

The purpose of this study was to validate the prognostic value of adding narrow-band imaging (NBI) during transoral laser surgery (TLS) for early glottic cancer.

METHODS

In 84 patients, 93 transoral laser resections were performed for carcinoma in situ (Tcis), T1, or T2 glottic cancer. TLS was preceded by intraoperative evaluation using traditional white-light imaging (WLI) in 51 cases. In 42 cases, NBI was used in addition to WLI. Local recurrence rate and recurrence-free survival were retrospectively compared between both groups.

RESULTS

Local recurrences developed in 14% of the 93 cases: 12 of 51 patients (24%) were treated by TLS based on WLI alone, and in 1 of 42 patients (2%) in the NBI group (P < .01). Two-year recurrence-free survival was 82% in the WLI group and 98% in the NBI group (P < .05).

CONCLUSION

Additional use of NBI during TLS for early glottic cancer significantly improves clinical outcome.

Evidence and evidence gaps of laryngeal cancer surgery

Surgical treatment of laryngeal cancer has been established for decades. In addition to total laryngectomy, which was first performed in 1873, a large number or organ preservation surgical techniques, like open partial laryngectomy, transoral laser microsurgery, and transoral robotic surgery have been developed. Studies on laryngeal cancer surgery are mainly retrospective case series and cohort studies. The evolution of chemoradiation protocols and their analysis in prospective randomized trials have led to an increasing acceptance of non-surgical treatment procedures. In addition to an improvement of prognosis, in recent years the preservation of function and maintenance of life quality after primary therapy of laryngeal cancer has increasingly become the focus of therapy planning. Significant late toxicity after chemoradiation has been identified as an important issue. This leads to a reassessment of surgical concepts and initiation of studies on laryngeal cancer surgery which was additionally stimulated by the advent of transoral robotic surgery in the US. Improving the evidence base of laryngeal cancer surgery by successful establishment of surgical trials should be the future goal.

Online estimation of laser incision depth for transoral microsurgery: approach and preliminary evaluation

BACKGROUND

The use of lasers in transoral surgery enables precise tissue incision with minimal adverse effects on surrounding structures. Nonetheless, the lack of haptic feedback during laser cutting impairs the surgeon's perception of the incision depth, potentially leading to undesired tissue damage.

METHODS

This paper presents a novel approach, based on statistical regression analysis, to estimate the laser incision depth in soft tissue. User trials were conducted in a laser surgery set-up, to verify the effectiveness of online estimation of incision depth in supporting precise tissue cutting.

RESULTS

The estimation accuracy was verified on ex vivo muscle tissue, revealing a root mean squared error (RMSE) of 0.1 mm for depths ranging up to 1.4 mm. Online estimation of depth has the potential to significantly improve the incision control of users.

CONCLUSIONS

The proposed approach was successful in producing estimations of laser cutting depth in ex vivo muscle tissue. Further investigation is required to validate this approach on other types of tissue. Providing depth estimation during laser cutting allows users to perform more precise incisions.

Partial laryngeal surgery in recurrent carcinoma

With the growing acceptance of nonsurgical therapies for laryngeal squamous cell carcinomas (LSCCs), it has become important to delineate surgical salvage strategies for disease recurrences. Total laryngectomy is often recommended, but appropriately selected laryngeal recurrences may be treated successfully with partial laryngeal surgery: laryngeal function can be preserved with oncological efficacy. The main available studies dealing with partial laryngeal surgery in recurrent carcinoma were critically reviewed. The most appealing feature of salvage transoral laser surgery (TLS) is the opportunity to make tumor-tailored excisions without any reconstructive limitations and retaining the option to switch to open partial laryngectomy. A recent detailed review of 11 series found a pooled local control rate of 57% after a first TLS procedure. Supracricoid laryngectomy (SCL) seems to achieve good local control rates in selected cases of recurrent supraglottic-glottic carcinoma: one review considering seven series calculated that 85% of the patients treated with salvage SCL after radiotherapy experienced no local recurrence; and total laryngectomy after failure of salvage SCL afforded an overall local control rate of 65%. Neck dissection is mandatory in all cases of local LSCC recurrence with evidence of neck metastases, and routine elective neck dissection is recommended for recurrent supraglottic and transglottic cancers.