Voice in early glottic cancer compared to benign voice pathology.

The purpose of this study is to compare (Dutch) Voice Handicap Index (VHIvumc) scores from a selected group of patients with voice problems after treatment for early glottic cancer with patients with benign voice disorders and subjects from the normal population. The study included a group of 35 patients with voice problems after treatment for early glottic cancer and a group of 197 patients with benign voice disorders. Furthermore, VHI scores were collected from 123 subjects randomly chosen from the normal population. VHI reliability was high with high internal consistency and test-retest stability. VHI scores of glottic cancer patients were similar to those of patients with voice problems due to benign lesions. Both groups of patients were clearly deviant from the normal population. Within the normal population, 16% appeared to have not-normal voices. Based on ROC curves a cut-off score of 15 points was defined to identify patients with voice problems in daily life. A clinical relevant difference score of 10 points was defined to be used for individual patients and of 15 points to be used in study designs with groups. Patients with voice problems after treatment for early glottic cancer encounter the same amount of problems in daily life as the other voice-impaired patients. The VHI proved to be an adequate tool for baseline and effectiveness measurement of voice.