Background: The prognosis of breast cancer has improved significantly during the last few decades increasing the interest in health-related quality of life (HRQoL). The aim of this study was to compare the HRQoL scores produced by different instruments and to shed light on their validity in various states of breast cancer by studying the association of cancer-related symptoms with HRQoL.
Material and methods: An observational, cross-sectional study of breast cancer patients treated in the Helsinki and Uusimaa Hospital District from September 2009 to April 2011. A total of 840 patients completed three HRQoL questionnaires: the EQ-5D-3L (including VAS), 15D and EORTC QLQ-30 and a questionnaire concerning sociodemographic factors. Patients were divided into five mutually exclusive groups: primary treatment (n = 118), recovery (6-18 months from diagnosis) (n = 150), remission (>18 months) (n = 382), metastatic disease (n = 176) and palliative care (n = 14). The association of HRQoL with sociodemographic and clinical factors and cancer-related symptoms, screened by the EORTC QLQ-30, was studied by multivariate modeling using stepwise linear regression analysis.
Results: HRQoL scores were the best at the time closest to diagnosis and deteriorated with disease progression. The EQ-5D had a pronounced ceiling effect with 40.8% of the respondents scoring 1 (perfect health) compared to 6% for the 15D and 5.6% for VAS. In regression analyses, pain, fatigue and financial difficulties were the most important predictors of lower HRQoL. The 15D showed better discriminatory power and content validity. The EORTC QLQ-C30 functioning deteriorated in advanced states of the disease with physical, social and role functioning being the most affected. Insomnia, fatigue and pain were the most commonly reported symptoms in all groups.
Conclusions: Different HRQoL instruments produce notably different HRQoL scores. The EQ-5D has a pronounced ceiling effect. Pain and fatigue are the most common symptoms associated with poor HRQoL in all disease states.