Voice outcomes following transoral laser microsurgery for early glottic cancer

Abstract

Voice and quality of life (QoL) are important considerations when comparing Transoral laser microsurgery (TLM) and radiotherapy (RT) as treatments for early glottic cancer (EGC). However, the postoperative voice and QoL profile following TLM is unclear and may be partly explained by methodological issues of current outcome measures. In this light, alternative measures were proposed. The first study investigated voice outcomes using validated acoustic measures for aperiodic voices. Voices were classified into one of four signal types according to degree of periodicity. As an alternative to traditional acoustic measures, smoothed cepstral peak prominence (CPPS) was used for the first time in this population. The second study combined voice-specific and health-related QoL measurement with components of The International Classification of Impairments, Activities and Participation (ICIDH-2) framework. Both studies examined the relationships between outcome measures and the influence of surgical and tumour factors on functional outcomes. The majority of participants had aperiodic signal types and were not considered suitable for traditional analysis. CPPS amplitudes were outside the normal range. Despite this, QoL was comparable to historical normative data. Those participants who underwent a greater number of laser episodes were more likely to exhibit worse acoustic voice and QoL outcomes. Increased time post-surgery and involvement of the anterior commissure was associated with voice impairment. Newly-applied acoustic measures were associated with each other, yet there was no relationship between QoL domains. The thesis highlighted the limitations of perturbation analysis and relevance of signal type and CPPS. QoL domains and components of the ICIDH-2 measure discrete constructs, highlighting the importance of multidimensional assessment of patient-perceived outcomes. Finally, the influence of number of laser episodes on voice and QoL may need to be investigated further.