Perceptual and Acoustic Outcomes of Early-Stage Glottic Cancer After Laser Surgery or Radiotherapy: A Meta-Analysis

Laser surgery (LS) or radiotherapy (RT) is normally recommended in early glottic cancer. The objective of this study was to perform a comprehensive meta-analysis of acoustic and perceptual outcomes to compare voice quality of LS or RT in early-stage glottic cancer. Data sources were obtained after searching PubMed, Google Scholar, EBSCO, and RISS using the following search terms: glottic cancer, glottic carcinoma, endoscopic surgery, laser surgery, radiotherapy, radiation, voice, voice quality, and grade, roughness, breathiness, asthenia, and strain (GRBAS) scale. Articles that compared voice outcomes between LS and RT were identified. This meta-analysis included 15 articles with 744 patients, including 400 in the LS group and 344 in the RT group. Random effects models were selected. Forest plots included standardized mean differences, standard errors, variance, 95% confidence intervals (lower limit to upper limit), z-values, and P-values. In perceptual analysis, grade (G) and asthenia (A) of RT were significantly better than LS. There was no statistically significant difference in roughness (R), breath (B), or strain (S) between LS and RT groups. Jitter, shimmer, and noise to harmonic ratio measurements showed significant differences, resulting in enhanced posttreatment effect of RT compared to LS. Results of our meta-analysis suggested that RT might lead to superior voice quality than LS in early glottic cancer.