Objective: This prospective follow-up study examines the psychometric properties of the World Health Organization Quality of Life assessment instrument (WHOQOL-100) for assessing quality of life in women suspected of having breast cancer and disease-free breast cancer survivors.
Study design and setting: The WHOQOL-100 was tested at five points in time in women with a palpable lump in the breast or an abnormality on a screening mammography (N=356) and breast cancer survivors (N=140). Furthermore, all participants completed measures of anxiety (State Trait Anxiety Inventory) and depression (Center for Epidemiologic Studies Depression scale). Moreover, women who were diagnosed with breast cancer also completed the EORTC-QLQ-BR-23 at time points 2-5. Reliability (internal consistency; test-retest reliability) and construct validity were tested.
Results: Confirmatory factor analyses on the WHOQOL-100 items showed a good fit with models reflecting six factors (physical health, psychological health, level of independence, social relationships, environment, spirituality/religion/personal beliefs) or four factors (physical health, psychological health, social relationships, environment). Internal consistency was adequate. Test-retest correlations were high. The WHOQOL-100 correlated highly with related constructs and showed low correlations with unrelated constructs.
Conclusion: The WHOQOL-100 is a reliable and valid instrument for measuring QOL in women suspected of having breast cancer and disease-free breast cancer survivors.