Cross-comparison of two quality of life instruments used in a randomized study of combination chemotherapy in advanced breast cancer

Abstract

Twenty-six patients from a randomized study of combination chemotherapy in advanced breast cancer were included in a cross-comparison between two quality of life instruments: a categorical linear analogue scale (C-LASA) based on the instrument of Priestman and Baum and a Swedish instrument developed by Glimelius et al. Quality of life was assessed on day 1 and day 10 of each chemotherapy cycle and the instruments were compared using correlation and kappa analysis. For the physical dimension, the mean correlation coefficient on day 1 was 0.89 and the kappa coefficient was 0.62; and on day 10 the correlation coefficient was 0.83 and the kappa coefficient 0.62. For the emotional dimension the correlation and kappa coefficients were 0.89 and 0.71 and 0.89 and 0.61 on days 1 and 10, respectively. The corresponding values for the global dimension were 0.76 and 0.56 and 0.80 and 0.57 on days 1 and 10, respectively. A correlation was also demonstrated over time. The instruments gave similar measurements of quality of life for chemotherapy-treated patients with advanced breast cancer, but the feasibility of the C-LASA instrument was better.