Elsevier

Journal of Voice

Volume 32, Issue 5, September 2018, Pages 636-642
Journal of Voice

Voice Outcomes after Radiotherapy Treatment for Early Glottic Cancer: Long-Term Follow-Up

https://doi.org/10.1016/j.jvoice.2017.08.025Get rights and content

Summary

Objectives

The aim of this study was to investigate long-term voice outcomes and voice-related quality of life (QOL) for early glottic cancer treated with radiotherapy.

Study Design

Long-term exploratory follow-up study of a prospective patient cohort comparing outcomes at a mean of 11 years postradiotherapy with the original 1-year posttreatment results.

Method

Eight patients completed voice tasks for auditory perception and acoustic and aerodynamic measures. Patient-reported voice-related QOL (VR-QOL) and voice quality were measured. Changes in outcomes over time were analysed using repeated-measures linear mixed models.

Results

Acoustic and aerodynamic outcomes remained stable from 1 year postradiotherapy to long-term follow-up, with only jitter mildly increasing from 1.9% at 1 year posttreatment to 2.8% (difference = 1.0%, 95% confidence interval [CI] = 0.1–1.9). Perceptually, voice remained relatively stable with only phonation breaks slightly increasing within the normal range, from 1.1 to 1.7 (difference = 0.6, 95% CI = 0.3–0.9) and breathy quality increasing from normal to slight impairment, with scores increasing from 1.8 to 2.4 (difference = 0.6, 95% CI = 0.3–1.1). QOL scores indicate a good level of VR-QOL that were unchanged at long-term follow-up when compared with 1 year posttreatment.

Conclusions

Improvement in voice outcomes found at 1 year postradiotherapy were largely maintained long term, with only minor changes observed. QOL scores indicate that a high level of VR-QOL was maintained many years after curative radiotherapy.

Introduction

Single-modality radiotherapy (RT) or laser surgery (LS) are well-established treatment options for the management of early glottic cancer, with both treatments providing high cure rates.1 With comparable cure rates for oncologic control and survival, decisions regarding optimal treatment may therefore be based on the functional outcomes achieved from either treatment.

The comparison of voice quality following RT or LS for early glottic cancer has been widely researched. While two earlier systematic reviews found no evidence to support superior outcomes for one treatment over the other,2, 3 a recent RCT study found better voice outcomes following RT with decreased breathiness.4 This was supported by another recent study which found better overall voice quality, emotional functioning and social contact for those treated with RT.5 One meta-analysis6 reported some advantages of voice outcomes for LS over RT. However, the number of studies analysed was small and with no RCT analysed with the selected studies. Currently the research indicates that RT has provided better voice outcomes following treatment, which is important knowledge given the known impact voice quality can have on quality of life (QOL).4, 5, 7

Although studies have reported on voice outcomes for early glottic cancer treated with RT, comparative research remains scarce due to the lack of agreed consensus of measurable functional outcomes and use of objective standardised measures.2, 8 In addition, there are only limited studies investigating voice as a multidimensional construct, exploring multiple aspects of voice such as vocal fold vibration, respiratory support (which may include vital capacity, pressure generation and abdominal/thoracic excursion), auditory-perceptual voice changes, as well as voice-related QOL (VR-QOL).8, 9, 10, 11, 12

Currently, there is also a lack of studies reporting patients' long-term quality of voice following curative treatment, with very few prospective studies exploring voice outcomes for early glottic cancer beyond 5 years. There is encouraging evidence for improved voice outcomes following RT. However, the research is largely limited to only 12 months8, 13, 14 and a 2-year follow-up.4, 11 Due to favourable cure rates and subsequent long-term survivorship, more research is needed beyond 2 years to ascertain voice quality over a prolonged period of time following RT treatment.

In summary, to date there are limited published data reporting long-term follow-up beyond 5 years, as well as limited research using multiple objective and standardised assessments. This study aims to address these gaps by investigating long-term voice outcomes with the use of objective and standardised assessments in a long-term exploratory follow-up on the same group of participants at 10–12 years posttreatment who were reported in an original study by Bibby et al.8 This original study used both instrumental and perceptual measures to assess voice quality changes and VR-QOL outcomes pretreatment and at 12 months posttreatment.

Section snippets

Original study

Between 2002 and 2004, 41 participants with newly diagnosed squamous cell cancer of the glottis (AJCC stage I or II) were recruited from the Peter MacCallum Cancer Centre for a study of voice outcomes. At 12 months posttreatment, 30 patients remained enrolled in the study. Explanations for patient dropout at 12 months posttreatment are outlined in Figure 1.

All participants received RT alone. Those with T1 lesions received 63 Gy radiation in 28 fractions over 5 weeks. Those with T2 lesions

Patient characteristics

The eight patients who consented to long-term follow-up (27% of the original cohort) were all male, with an average age of 65 years at baseline and 76 years at follow-up. The length of follow-up varied for each patient but ranged between 10 and 12 years, and was on average 11 years. From this point on “long-term follow up” within this manuscript will refer to 10–12 years. The demographic and clinical characteristics of the participants are shown in Table 1. Of note, none of the participants

Discussion

This is the first long-term follow-up study of more than 10 years posttreatment evaluating quality of voice outcomes for patients treated with RT for early glottic cancer. This study demonstrates that, overall, patients' voices improved following RT and that there was no significant deterioration over the following 10 years.

The original study by Bibby et al8 reported a statistically significant improvement in voice quality from pretreatment to 12-month follow-up, with improvement in all aspects

Acknowledgments

We would like to acknowledge and thank the Speech Pathology Department, School of Allied Health, La Trobe University, for loaning the equipment to perform the voice recordings and for providing access to the computer software for voice analysis; the speech pathologists, Georgia Magarey and Dailan Evans, for taking the time to analyse the voice samples; and last but not least the willing participants who gave their time to participate in this follow-up study.

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