An Objective Assessment of Voice Production after Radiation Therapy for Stage I Squamous Cell Carcinoma of the Glottis

Abstract

Radiation therapy has been the primary treatment for early glottic carcinoma, especially when restoration of normal voice is essential; yet objective evidence of the status of vocal function after treatment is lacking. The purpose of this study was to assess vocal characteristics of patients with glottic carcinoma after they had undergone radiation therapy. Twenty males, who had previously been treated with external beam irradiation for T1NOMO squamous cell carcinoma with no subsequent evidence of recurrence, volunteered for this study. Laryngovideostroboscopic, acoustic, aerodynamic, and perceptual measures of vocal function were used to determine the characteristics of voice production. Acoustic indices were compared to those of a normal group of 30 age-matched volunteers, and the other measures were compared to established values reported in the literature. On acoustic analysis, the study group was characterized by significantly worse voice production than their counterparts. A high degree of intersubject variability was noted that could not be accounted for in terms of variables in treatment and medical history. The aerodynamic, spectral, and video-stroboscopic findings correlated well; this indicated a poor vibratory source, characterized by diffuse stiffness. Further work is necessary in order to compare vocal function after endoscopic laser and conventional conservative excision.