Objective: To determine the feasibility and sensitivity of the WHOQOL-BREF-THAI assessment tool in measuring the quality of life in cancer patients treated with radiotherapy in routine clinical practice.
Method: A cross-sectional analytical study including the consecutive radiotherapy patients at Songklanagarind Hospital from October to December 2000 was conducted. The participants completed a Thai version of the brief form of the WHO quality of life assessment instrument (WHOQOL-BREF-THAI).
Results: The majority of the patients (80.7%) were able to complete the questionnaire, 19 (12.6%) by themselves, 4 (2.6%) with the help of their relatives and 128 (84.8%) through the interview. Almost all of them could understand the questions very well. The mean and standard deviation of time requirement in completing it were 13.0 + 4.0 minutes. The WHOQOL-BREF-THAI instrument was sensitive enough to discriminate the QOL in patients with differences in all analyzed clinical parameters, which were hospitalization, stage of disease, treatment aim and ECOG performance status.
Conclusion: The present results supported the feasibility of using the WHOQOL-BREF-THAI assessment tool in radiotherapy cancer patients with good sensitivity and patient understanding within an acceptable time requirement. One practical barrier of concern was a low self-assessment percentage in this particular group of patients, necessitating the interviewer system.

Keywords: Quality of Life, Cancer, Radiotherapy, WHOQOL-BREF-THAI