Impact of ipsilateral false vocal fold resection on swallowing following transoral laser cordectomies - a pilot study

doi:10.21203/rs.3.rs-3230352/v1

Download PDF

Article

Impact of ipsilateral false vocal fold resection on swallowing following transoral laser cordectomies - a pilot study

https://doi.org/10.21203/rs.3.rs-3230352/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Our aim was to investigate the early and late impact of false vocal fold removal (vestibulectomy) on swallowing using fibreoptic endoscopic evaluation of swallowing (FEES) following type III, IV and V transoral laser cordectomies (TLC). Fifteen endoscopically resectable glottic cancers necessitating TLC with vestibulectomy were included. FEES was performed preoperatively and in both the early and late postoperative periods establishing modified penetration aspiration scale (mPAS) and pharyngeal residue severity scale (PRSS). Laryngeal preservation and local recurrence were also noted. Due to 10 T1a, 2 T1b, 2 T2 and 1 selected T3 diseases, 2 type III, 9 type IV, 2 type Va and 2 type Vd cordectomies were performed. Early and late average postoperative PRSS scores were 1 and 0, respectively, while early and late postoperative mPAS scores were identically 1. Neither early nor late postoperative PRSS and mPAS values (0 and 1, respectively) differed remarkably from preoperative scores. Laryngeal preservation failed in only one case due to recurrence. TLC provides excellent laryngeal preservation in early glottic cancer. In our series, ipsilateral vestibulectomy during TLC did not deteriorate swallowing neither by increased pharyngeal residue nor by increased aspiration risk. Nevertheless, a higher case number is recommended to statistically confirm our observations.

Biological sciences/Cancer

Health sciences/Health care

Health sciences/Medical research

Health sciences/Oncology

Transoral CO₂ laser cordectomy (TLC) under proper exposure is considered as the most efficient minimally-invasive surgical treatment regarding early stage (T1-T2) and eventually selected T3 glottic cancers. During transmuscular and ”deeper” endoscopic cordectomies, classified by European Laryngological Society (ELS) [1], resection of the false vocal fold (also known as vestibulectomy) is recommended for better cancer visualization. However, false vocal fold plays an important role in airway protection by narrowing the supraglottis in the pharyngeal phase of swallowing. Therefore, removal of this structure may risk penetration/aspiration in the postoperative period despite ELS recommendation. To the best of our knowledge, to date only one endoscopic swallow study has been published in connection with TLCs, but it only focuses on penetration/aspiration using a 3 point scale following type V cordectomies with or without false vocal fold removal [2]. Therefore, we aimed to investigate the impact of false vocal fold resection not only on penetration/aspiration but on pharyngeal residue as well with fibreoptic endoscopic evaluation of swallowing (FEES) after TLC. As secondary end-points, laryngeal preservation rate and local recurrence rate were also evaluated.

Fifteen eary glottic cancers associated with consensual regular tobacco user patients (13 males, 2 females, average age 66 years) were enrolled in this pilot study between January 2015 and January 2023. All procedures in our study were performed with the approval of the Regional Research Ethics Committee, Clinical Centre, University of Pécs (record number: 5564-PTE 2014) considering the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study. Inclusion criteria were endoscopically resectable primary early stage (T1-T2) glottic cancer and medical eligibility for general anesthesia. Patients afflicted with dysphagia of any origin or previous radiotherapy were excluded. Patient data (age, gender), tumor stage and co-morbidities which can influence swallowing are demonstrated in Table 1.

Clinical diagnosis of early stage (T1-T2) glottic cancer was confirmed prior to TLC by preliminary suspension microlaryngoscopy, CT scan, biopsy and histopathological examination. Following approval of the treatment plan by our multidisciplinary tumor board, patients underwent TLC. The procedures were performed under general anesthesia with suspension microlaryngoscopy. Prior to tumor removal, 0⁰ and 30⁰ rigid endoscopes with 1 cm width, 55 cm length (Karl Storz^®, Tuttlingen, Germany) were used once again for surveying tumor extent. KLS Martin CO₂ laser (KLS Martin^®, Tuttlingen, Germany) was attached to a Leica operating microscope (Leica^®, Munich, Germany). The focused laser beam was guided by a micromanipulator. For increased perspective of the glottic cancer, ipsilateral false vocal fold was removed in every case. Tumor excision was carried either into the thyroarytenoid muscle or to the inner surface of the thyroid and cricoid cartilage depending on the desired extent of cordectomy. Regarding the surgical principles, we adhered to the ELS proposal for endoscopic cordectomies. The excised tumor specimens were oriented over a segment of sponge using colored pins repesentative during the histopathological examination. Following cordectomy, rigid endoscopes with 0⁰ and 30⁰ field of view were used to examine eventual tumor residue in the surgical bed (Figure 1). After a thorough endoscopic overview of the surgical field, additional biopsies were taken from the adjacent soft tissue when it was feasible to exclude tumor remnant. All participants had undergone FEES in estimating swallow performance preoperatively, in the early (1 week) and in the late (4 months) postoperative period, respectively.

Flexible chip-on-tip laryngofibreoscope (Atmos^®, Lenzkirch, Germany) was introduced through the most patent nostril till the level of the velum without topical anesthesia. After evaluating laryngeal-pharyngeal anatomy, motion of both hemilarynges were examined (Figure 2). Sensory function of the larynx and hypopharynx were tested by contacting subregions using the tip of the scope. Afterwards, test boluses of mushy and liquid consistencies created from food thickening powder and colored with different food dyes were administered to each patient. Pharyngeal Residue Severity Scale (PRSS)[3] and modified Penetration Aspiration Scale (mPAS)[4] were used for evaluation of pharyngeal bolus residue and eventual penetration/aspiration, respectively (Table 2). Oncological follow-up examination was conducted for all patients as indicated by NCCN guidelines [5]. Laryngeal preservation rate and local recurrence as secondary outcomes was also noted to assess efficiency of cordectomies.

Transoral laser cordectomy

Among the enrolled fifteen patients, 10 T1a, 2 T1b, 3 T2 primary tumor stages were diagnosed based on the preoperative examination and diagnostic microlaryngoscopy. No neck or distant metastasis were discovered upon review of the CT scans in all subjects. All cases proved to be keratinizing squamous cell carcinoma upon histopathological examination. In regards to the extension of TLCs, type III (2 cases), IV (9 cases) and V (4 cases) cordectomies were performed, respectively. Primary tumor stages and the type of cordectomy are also detailed in Table 1.

All tumors could be resected with macroscopically safe margins. Histopathological evaluation unveiled superficial positive margins (R1 resection) in 5 out of 15 cases. In one case, a T2 cancer was up-staged to T3 intraoperatively, due to the obvious involvement of the paraglottic space which was not apparent in the preoperative CT scan. Only in this sole case was adjuvant radiotherapy indicated regarding management of the neck according to guidelines. There were no major intra- or postoperative complications (e.g., laryngeal edema, bleeding and/or transoral unresecability) in our series which required tracheotomy or conversion to open surgery. Only a mild subcutaneous emphysema of the neck and chest wall occurred in one of the type Va cordectomy cases on the first postoperative day which was spontaneously resolvled by the third day. During the average 55 month follow-up period, due to lack of compliance, two advanced local recurrences developed (2 of 15 cases). One patient received definitive radiotherapy, while the other patient required a total laryngectomy. Thus, laryngeal preservation was achieved in 14 out of 15 patients. Nevertheless, all patients were tumor-free by the end of the study.

Fibreoptic endoscopic evaluation of swallowing

FEES was well tolerated by all participants. Neither bleeding nor postprocedural pneumonia occurred. The average preoperative mPAS and PRSS values (1 and 0, respectively) were without deviation reflecting physiological swallowing. In both the early postoperative period (within 1 week following TLC) and in the late postoperative phase (4 months following surgery), the average mPAS values invariably scored 1, respectively. TLCs were followed by marked pharyngeal residue (coating) within 1 week (average PRSS value: 1). Following complete healing, following four months, no residue was observed. In consideration of the patient afflicted with Parkinson’s disease, the oral phase was mildly affected by predeglutitive leakage of liquid. PRSS and mPAS values are presented in Table 1.

TLC is still the gold standard in minimal-invasive surgical treatment regarding early stage glottic cancers. The efficiency has been considered equivalent to radiotherapy in point of local tumor control for a lengthy period of time [6–8]. However, several studies found TLC superior to primary radiotherapy in local tumor control and/or larynx preservation in early stage glottic cancers [9–12]. When applied as monomodality, it can ”spare” definitive radiotherapy as a salvage solution in case of transorally uncontrollable recurrences prior to total laryngectomy. Cordectomy types are well classified by the proposal of ELS. ELS recommendations clearly proposes false vocal fold removal (vestibulectomy) for improved tumor exposure starting from transmuscular cordectomies [1]. Evidently, in the lack of a false vocal fold, a laser excision line can be guided laterally, in particular, to the inner lamina of the thyroid cartilage. Despite this rational proposal, to our best knowledge, no FEES study as of yet has comprehensively investigated the possible negative impact of false vocal fold removal on swallowing including both penetration/aspiration and pharyngeal residue, although false vocal folds obviously play non-negligible role in airway protection during swallowing. On one hand, these folds represent a valuable sensory surface. From another perspective, false vocal folds behave as a barrier against penetration by adduction during the pharyngeal phase of swallowing.

In our study, we investigated the presence and severity of pharyngeal residue and penetration/aspiration as the primary fields of interest. PRSS and mPAS introduced by Kelly [3, 4], respectively, are considered easily applicable scales in daily routine by our team. Preoperative average PRSS and mPAS values ”0” and ”1”, respectively, referred to healthy swallow performance among our patients. In considering the mPAS value, it did not change, neither in the early nor in the late postoperative period. In regards to pharyngeal residue, during the early postoperative period, the PRSS value increased to ”1” compared to the baseline preoperative value ”0” referring to coating of the test bolus in the vallecules or in the hypopharynx. The possible explanation for the appearance of coating is a temporary sensory deficit of the pharyngeal mucosa. It can develop due to irritation of the mucosal surfaces during orotracheal intubation and during an overview of the hypopharynx with laryngoscope prior to focusing on intralaryngeal exposure of the tumor. This supposed temporary phenomenon presumably ceases, as late postoperative PRSS value returns the initial ”0”. Upon closer examination of the early postoperative mPAS values, one likely notes, some individual values show an increase when compared to preoperative and late postoperative ”normal” values. The origin of this transient swallow impairment can be the same as in the case of pharyngeal residue, since lack of the false vocal fold deprives the supraglottis from a sensory surface. Beyond sensory disturbance, due to the lack of false vocal fold, supraglottic adduction is also inadequate. It is important to notice among patients showing temporary swallow impairment based on both mPAS and PRSS, several subjects experience neurological involvement including Parkinson’s disease and poststroke conditions. Diabetes mellitus also can cause decreased sensory function due to consecutive polyneuropathy. All possible theories behind temporarily disturbed swallow performance mentioned above are to be kept in mind.

In consideration of local tumor control, TLC proved excellent among those thirteen patients who attended regular check-ups. Two patients who developed advanced tumor recurrence presented poor compliance and neglected follow-up for more than two years. At the time regarding repeated examination, one patient was diagnosed with T3N0M0 of glotto-supraglottic cancer necessitating definitive radiotherapy. The other patient was afflicted with a T4aN0M0 glotto-supraglottic cancer which only could be controlled by total laryngectomy. In the case, when T2 cancer had to be upstaged to T3 due to paraglottic involvement, the tumor as a selected T3 case also was managed transorally, yet definitive radiotherapy had to be indicated. At the conclusion of the investigational period, all fifteen patients proved tumor-free and the only exception was the one laryngectomized patient. Undoubtedly, larynx preservation proved successful in our series.

Interestingly, positive resection margins uncovered in one third of the cases (none of which were related to our two recurrent cases) did not entail local recurrence. Matter of positive resection margins and its prognostic value concerning local recurrence is an intensively investigated issue. The 1–2 mm safety margin in reference to glottic cancers proposed by NCCN Guidelines® [5] cannot be achieved in a majority of the cases. During complete or extended cordectomies, tumor removal requires reaching the thyroid and cricoid cartilage. Owing to the tumor size necessitating these cordectomy extensions, this proposed safety width can be hardly found. The other problem is the coagulational zone created by the laser, further reducing the safety zone of the specimen. The formalin-associated specimen shrinkage is the other undesirable tissue change which can unfavorably influence estimation of safety margins resulting in false-positive cases mimicking R1 resection. Therefore, positive or close/suspicious surgical margins do not necessarily predict local recurrence [13, 14]. For this reason, in the spirit of maximal patient safety, a close follow-up and/or scheduled biopsy under general anesthesia is recommended. Considering our clinical practice, similarly to other authors [15], as an additional safety step, we take multiple biopsies from the neighboring soft tissue which bears additional information regarding the quality of resection.

Nevertheless, we are aware of the disadvantages of the study, therefore we consider our investigations as a pilot study. Additionally, enlargement of our cases are needed for verifying our results statistically. Although the issue of older aged patients and associating presbyphagia as factors influencing swallowing could not be excluded in the present study, investigation of a less heterogenous patient group will be considerable since these conditions including diabetes and neurological diseases (e.g., Parkinson’s disease, stroke) may also distort results.

TLC providing excellent local tumor control is a valuable procedure in the treatment of early stage glottic cancers. Our initial observations do not contradict resecability of ipsilateral false vocal fold during TLCs regarding swallowing. Comprehensively, investigation of more cases without co-morbidities influencing swallowing is recommended.

Author contributions

All authors contributed to the intellectual development of the manuscript. BA had the original idea, BA and KS designed the project and drafted the manuscript under the supervision of SZI. BA performed the surgical interventions and carried out the follow-up. BA and KS performed the fibreoptic endoscopic evaluation of swallowing and recorded mPAS and PRSS scores. SZI supervised each worksteps.

Additional information

Competing interest: The author(s) declare no competing interests.

Data availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

Remacle M et al. Endoscopic cordectomy. A proposal for a classification by the Working Committee, European Laryngological Society. Eur Arch Otorhinolaryngol 2000; 257(4):227–31.
Peretti G et al. Function preservation using transoral laser surgery for T2-T3 glottic cancer: oncologic, vocal, and swallowing outcomes. Eur Arch Otorhinolaryngol 2013;270(8):2275–81.
Kelly AM, Leslie P, Beale T, Payten C, Drinnan MJ. Fibreoptic endoscopic evaluation of swallowing and videofluoroscopy: does examination type influence perception of pharyngeal residue severity? Clin Otolaryngol 2006; 31(5):425–32.
Kelly AM, Drinnan MJ, Leslie P. Assessing penetration and aspiration: how do videofluoroscopy and fiberoptic endoscopic evaluation of swallowing compare? Laryngoscope 2007; 117: 1723–1727.
Caudell JJ et al. NCCN Guidelines® Insights: Head and Neck Cancers, Version 1.2022. J Natl Compr Canc Netw. 2022;20(3):224–234.
Ferreira N et al. Surgery versus radiotherapy: Long term outcomes of T1 glottic cancer. Rep Pract Oncol Radiother. 2020;25(6):860–866.
Rosier JF et al. Comparison of external radiotherapy, laser microsurgery and partial laryngectomy for the treatment of T1N0M0 glottic carcinomas: a retrospective evaluation. Radiother Oncol 1998; 48(2):175–83.
Osborn HA et al. Comparison of endoscopic laser resection versus radiation therapy for the treatment of early glottic carcinoma. J Otolaryngol Head Neck Surg 2011;40(3):200–4.
Kerr P et al. Oncologic and voice outcomes after treatment of early glottic cancer: transoral laser microsurgery versus radiotherapy. J Otolaryngol Head Neck Surg 2012;41(6):381–8.
Yoo J, Lacchetti C, Hammond JA, Gilbert RW. Role of endolaryngeal surgery (with or without laser) versus radiotherapy in the management of early (T1) glottic cancer: a systematic review. Head Neck 2014;36(12):1807–19.
Lois-Ortega Y, García-Curdi F, Sebastián-Cortés JM, Miguel-García FD, Vallés-Varela H, Muniesa-Del Campo A. Radiotherapy versus laser microsurgery in the treatment of early glottic cancer. Acta Otolaryngol 2020;140(11):954–958.
Huang G, Luo M, Zhang J, Liu H. Laser surgery versus radiotherapy for T1a glottic carcinoma: a meta-analysis of oncologic outcomes. Acta Otolaryngol 2017;137(11):1204–1209.
Mariani C et al. Management and Oncologic Outcomes of Close and Positive Margins after Transoral CO2 Laser Microsurgery for Early Glottic Carcinoma. 2023;27;15(5):1490.
Fiz I, Mazzola F, Fiz F, Marchi F, Filauro M, Paderno A. Impact of Close and Positive Margins in Transoral Laser Microsurgery for Tis-T2 Glottic Cancer. 2017;16;7:245.
Hendriksma M, Montagne MW, Langeveld TPM, Veselic M, van Benthem PPG, Sjögren EV. Evaluation of surgical margin status in patients with early glottic cancer (Tis-T2) treated with transoral CO2 laser microsurgery, on local control. Eur Arch Otorhinolaryngol 2018;275(9):2333–2340.

Table 1 to 2 are available in the Supplementary Files section.

No competing interests reported.

Table1.xlsx
Patient data including age, gender, co-morbidities and tumor stage, type of cordectomy, length of follow-up, local recurrence, larynx preservation data completed with preoperative and postoperative PRSS, mPAS values
Table2.xlsx
Detailed description of modified Penetration Aspiration Scale (mPAS) and Pharyngeal Residue Severity Scale (PRSS)

Download PDF

Version 1

posted

You are reading this latest preprint version

Impact of ipsilateral false vocal fold resection on swallowing following transoral laser cordectomies - a pilot study

Status:

Version 1

Abstract

Figures

Introduction

Material and method

Results

Discussion

Conclusion

Declarations

References

Tables

Additional Declarations

Supplementary Files

Status:

Version 1