Factors affecting the quality of voice in the early glottic cancer treated with radiotherapy.

Aims: To prospectively analyze the objective voice quality before and after radiotherapy (RT) for early glottic cancer and to evaluate the role of different factors that may affect it.

Methods: Patients with T1-T2N0M0 glottic cancer underwent voice quality assessment before treatment and after radical RT. Post-RT voice quality was compared to the voice at diagnosis and the voice of healthy individuals used as controls. A comprehensive set of voice parameters were measured. The effects of age, smoking history, T stage, anterior commissure (AC) involvement, radiation dose, fractionation and volumes on pre-treatment and post-treatment voice quality were analyzed.

Results: The voice quality data of 50 patients were analyzed. Following treatment, there was a significant improvement in the majority of measured parameters. However, perturbation and HNR remained inferior compared to controls. A history of smoking, AC involvement and larger RT volumes resulted in poorer voice parameters following RT. There was no significant impact of age alone. T2 tumors had an inferior voice quality before treatment, but did not remain inferior following RT. Hypofractionated RT did not show any negative impact.

Conclusions: There is a considerable improvement of voice quality following RT. Several factors may have specific effects on pre-treatment and post-treatment voice.