Factors Affecting Voice Quality in Early Glottic Cancer Before and After Radiotherapy

BACKGROUND: Radiotherapy (RT) is a successful mode of treatment for early glottic cancer. The aim of the study was to assess voice quality both before and 3 months after successful RT using multimodal methods while also identifying the factors affecting it. PATIENTS AND METHODS: In 50 patients with T1 glottic carcinoma, the subjective (patients’ assessment of voice quality [VAS], Voice Handicap Index [VHI] questionnaire, phoniatricians’ assessment using the grade/roughness/ breathiness [GRB] scale), and objective assessments (fundamental laryngeal frequency [F(0)](,) jitter, shimmer, maximum phonation time [MPT]) of voice quality were performed before RT and 3 months post-RT. The data on gender, age, extent of the tumors, biopsy types, smoking, local findings, and RT were obtained from the medical documentation. RESULTS: Three months after the treatment, VAS, VHI, G and R scores, F(0), and MPT significantly improved in comparison with their assessment prior to treatment. Before the treatment, the involvement of the anterior commissure significantly deteriorated jitter (p = 0.044) and the involvement of both vocal folds deteriorated jitter (p = 0.003) and shimmer (p = 0.007). After the RT, F(0) was significantly higher in the patients with repeated biopsy than in the others (p = 0.047). In patients with post-RT changes, the B score was significantly higher than in those without post-RT changes (p = 0.029). CONCLUSIONS: Voice quality already significantly improved three months after the treatment of glottic cancer. The main reason for the decreased voice quality prior to treatment is the tumor’s extent. Post-RT laryngeal changes and repeated biopsies caused more scarring on vocal folds adversely influencing voice quality after the treatment.