Spectro-acoustic voice parameters in transoral laser microsurgery vs exclusive radiotherapy for early-stage glottic carcinoma: A systematic review and meta-analysis

Purpose: In early glottic squamous cell carcinoma, similar results have been described in terms of disease control between transoral laser microsurgery (TLM) and radiation therapy (RT). During the past two decades, several studies compared subjective vocal outcomes of exclusive RT with those of TLM, showing a trend towards improving results for TLM over time. However, the objective differences in terms of spectro-acoustic voice parameters between exclusive RT and TLM have been less frequently investigated. The aim of this systematic review with meta -analysis was to evaluate voice quality after TLM and RT treatment for early glottic carcinoma, based on acoustic analysis parameters including jitter, shimmer, noise to harmonic ratio, fundamental frequency and maximum phonation time. Material and methods: A search of the English published literature was conducted on the Pubmed, Scopus and Cochrane databases following PRISMA guidelines. Results: A total of 441 titles were retrieved from the search. After full -text screening and application of inclusion/ exclusion criteria, 12 articles were included. We found no significant differences between TLM and RT treatment in the considered acoustic analysis parameters, except for Shimmer, with more favorable values reported in the RT group. Conclusions: Considering the spread of the disease and expecting an improvement in long-term survival over time, well-designed and multicentric studies involving larger populations with a long-term follow up are mandatory to better assess objective voice outcomes in terms of spectro-acoustic voice parameters.