Measurement of quality of life in women with breast cancer before and after adjuvant chemotherapy: A structural equation modelling

Abstract

e11513 Background: This study examines breast cancer patients’ individual changes in health related quality of life (HRQOL) measures over time and the relationships between these measures within the framework of Structural equation modeling (SEM). Methods: One hundred and fifty five Australian women with breast cancer were asked to complete the Functional Assessment of Cancer Therapy Breast, Version 4 (FACT-B) pre- and post-chemotherapy as measures of HRQOL. In SEM, growth curve modelling was required for the estimation of individual differences in developmental changes of HRQOL scales over time. A growth mixture model was also used for identifying the cross-group differences in the pattern of changes in a given population over time. Results: Reliability and validity of the FACT-G including the fatigue subscale and breast cancer subscale for evaluating Australian breast cancer patients was determined to be sufficient for research purposes. After adjustment for covariates, two subgroups of women were identified with respect of patterns of response, representing largely increasing and decreasing trends in HRQOL respectively. In the former group, on average 85% of breast cancer women reported changes over time with respect to individual HRQOL measures and 78% reported such changes with respect to combined HRQOL Scores. A small group of women reported changes with respect to HRQOL measures in the decreasing group. The greatest contribution to variation in HRQOL measures was in the breast cancer subscale for both individual and combined scores. Subsequent factor analysis of the breast cancer subscale revealed that with one exception, all items loaded onto three separate factors described as self-esteem, physical and psychological. The latter two improved over time, but self- esteem was largely unchanged. Conclusions: The study presents a technique that allows us to identify potential subgroups of study subjects that experience different trajectories of responses. The results of this study provide greater insight into HRQOL changes over time and can help to plan interventions in a better way, ultimately contributing to improvement in HRQOL of women with breast cancer. No significant financial relationships to disclose.