Clinical investigation: Reliability and validity of the Japanese version of quality of life radiation therapy instrument (QOL-RTI) for Japanese patients with head and neck malignancies.

PURPOSE

To evaluate the reliability and validity of the Japanese translation of Quality of Life Radiation Therapy Instrument (QOL-RTI) and the head and neck module (H&N) for Japanese patients being treated with radiotherapy for head and neck malignancies.

MATERIALS & METHODS: The QOL-RTI/H&N was translated into Japanese by a preliminary QOL research working group of JASTRO and was used in this clinical trial. From 1998 to 2001, 70 patients with head and neck malignancies for whom radical radiotherapy was planned were entered into this study. Patients were requested to answer the questions before radiotherapy at baseline, twice during week 4 of therapy (for test-retest reliability), at the end of treatment, and 3 months, 6 months, 1 year and 2 years from the beginning of radiotherapy. Internal consistency was assessed by Cronbach's alpha coefficient. Validity was assessed by comparing the results with EORTC-QLQ-C30 and with QOL questionnaire for cancer patients treated with anticancer drugs (QOL-ADC). Patient compliance and test sensitivity were also analyzed.

RESULTS

Cronbach's alpha coefficient was 0.79 to 0.93 depending on the time point for the evaluation. Test-retest reliability was acceptable, with a Pearson coefficient of 0.83 for QOL-RTI and 0.92 for H&N module. Compliance with this scheme was 98.2%. The QOL-RTI was sensitive enough to detect significant changes in the QOL score during and after the course of radiotherapy. Agreement with the EORTC-C30 was good with a high Pearson correlation coefficient of 0.648 and that with QOL-ADC was also good with a coefficient of 0.566. The factors analyzed consisted of 11 functional/health-oriented questions, 5 emotional/ psychological, 5 socio-economic/ family and 2 general.

CONCLUSION

The Japanese version of QOL-RTI with H&N module was found to be reliable and sensitive enough to evaluate variation of QOL in patients with head and neck malignancies during and after radiotherapy.