Quality-of-life valuations of advanced breast cancer by New Zealand women.

OBJECTIVES: To obtain health-related quality-of-life (HR-QOL) valuations (or 'utilities') from New Zealand women for four health states representative of advanced (metastatic) breast cancer, suitable for use in cost-utility analysis, and to compare four valuation methodologies.
METHODS: Written case descriptions of four health states representative of advanced breast cancer (hormonal therapy, chemotherapy, radiotherapy and hypercalcaemia) were developed in consultation with nine oncology professionals. Time trade-off (TTO) and visual analogue scale (VAS) valuations were obtained via interviews from a sample of 50 women, aged 25-69 years, randomly selected from the New Zealand general public and through informal networks. Representations of the four health states on the EQ-5D health state classification system were also obtained from the respondents and later valued using New Zealand and UK EQ-5D social tariffs.
RESULTS: The four valuation methods ranked the four states' mean valuations identically: hormonal therapy > chemotherapy > or = radiotherapy > hypercalcaemia. All methods except the TTO distinguished between chemotherapy and radiotherapy. In order of the VAS and TTO methods and the EQ-5D with NZ and UK tariffs, respectively, the valuations [mean (95% CI)] were: hormonal therapy 0.54 (0.48, 0.59); 0.65 (0.57, 0.73); 0.54 (0.51, 0.58); 0.60 (0.54, 0.65); chemotherapy 0.46 (0.41, 0.51); 0.49 (0.40, 0.57); 0.48 (0.43, 0.53); 0.51 (0.43, 0.59); radiotherapy for severe bone pain 0.35 (0.30, 0.40); 0.45 (0.37, 0.54); 0.31 (0.27, 0.35); 0.25 (0.18, 0.33); and moderate to severe hypercalcaemia 0.13 (0.09, 0.17); -0.17 (-0.29, -0.05); -0.05 (-0.07, -0.03); -0.52 (-0.56, -0.48). The four valuation methods gave similar results for chemotherapy, but for the three other states the TTO valuations differed from those obtained from the VAS method and the NZ and UK EQ-5D tariffs. There were significant pairwise correlations between the four methods across all four health states, although the valuation for hypercalcaemia obtained from the UK EQ-5D tariff was very low compared with the three other methods, and the VAS valuation was positive rather than negative.
CONCLUSION: Our study suggests that women in the New Zealand general public are able to consistently evaluate and value case descriptions of advanced breast cancer using either direct methods (VAS or TTO) or the EQ-5D health state classification system. Some of the valuations elicited using the four methods differ quantitatively, especially for hypercalcaemia. As our sample size was modest (50) and it turned out to be unrepresentative of the New Zealand female population, this study serves as a pilot study.