Validation of EORTC QLQ-C30 and QLQ-BR23 questionnaires in the measurement of quality of life of breast cancer patients in Singapore

OBJECTIVE To validate EORTC QLQ-C30 and EORTC QLQ-BR23 questionnaires and to measure the health-related quality of life (HRQOL) of women with breast cancer in Singapore during their first 4 years of post-diagnosis and treatments. METHODS A quantitative and cross-descriptive sectional study. All of 170 subjects were recruited in a Singapore tertiary cancer center. The European Organization for Research and Treatment-QOL questionnaire and breast cancer specific module (EORTC QLQ-C30 and QLQ-BR23) were used to measure the HRQOL among women with breast cancer. All statistical tests were performed using SPSS Version 18. The reliability of the EORTC QLQ-C30 and QLQ-BR23 questionnaires was examined using Cronbach's alpha test. EORTC QLQ-C30 was validated against EuroQol Group's 5-domain questionnaires (EQ5D) by examining its concurrent validity using Pearson Product Moment Correlation to calculate the total scores. RESULTS The Cronbach's alpha coefficient results for EORTC QLQ-C30 and QLQ BR-23 were 0.846 and 0.873 respectively which suggested relatively good internal consistency. The correlation between EORTC QLQ-C30 and EQ5D QOL instruments demonstrated a modest linear relationship (r=0.597; P<0.001) that indicated a moderately strong correlation between the two measures. The study showed that Singaporean women with breast cancer had enjoyed high levels of HRQOL during their first 4 years of survivorship but they had significant concern over the financial impact of breast cancer. One of the key findings was younger women had experienced more physical and psychosocial concerns than older women. CONCLUSION The EORTC QLQ-C30 and QLQ-BR23 questionnaires are feasible and promising instruments to measure the levels of HRQOL in Singaporean women with breast cancer in future studies.