Objective evaluation of the quality of voice following radiation therapy for T-1 glottic cancer

Background: Radiation therapy is commonly considered the treatment of choice for T-1 glottic cancer. While it is generally believed that the quality of voice following irradiation is quite satisfactory, few studies have reported the results of objective assessment of voice after radiation therapy. Purpose: To objectively evaluate the quality of voice following radiation therapy for T-1 glottic cancer. Materials and methods: The voices of 12 patients treated for T-1 glottic cancer with radiation therapy were evaluated by acoustic analysis and speech aerodynamic studies. Eleven patients received between 6300 and 6665 cGy at a daily fraction size of 180-225 cGy. One patient received 7000 cGy at a daily fraction size of 200 cGy. Evaluation of the quality of voice was done 3 months to 7 years following completion of radiation therapy. Results: The number of patients who scored abnormal values for the measurements of fundamental frequency, jitter, shimmer and harmonic to noise ratio was 2, 10, 4 and 3, respectively. The number of patients who scored abnormal values for transglottic airflow rare, subglottal pressure and glottal resistance was 12, 8 and 9, respectively. None of the studied patients scored normal values in all given tests. Conclusion: Although radiation therapy cures a high proportion of patients with T-1 glottic cancer, the quality of voice does not return to normal following treatment. (C) 1997 Elsevier Science Ireland Ltd.