Life quality assessment of breast cancer patients receiving adjuvant therapy using incomplete data.

Previous research on the effects of adjuvant treatment for women with operable breast cancer focused exclusively on disease-free and overall survival. In this study we evaluate life quality of premenopausal node-positive breast cancer patients receiving adjuvant chemotherapy for at least three months. For the first time, a modified latent variable model is used to assess treatment outcome in a prospective clinical trial. This poses a number of econometric problems which did not occur in the preceding studies. One of them is how to deal with patients whose records are incomplete. The data are provided by the International Breast Cancer Study Group (study VI). The results indicate that the lowest dose treatment improves life quality faster than the remaining three alternatives. At the end of the 24 months observation period no significant differences between the four treatment options remain. Although the lowest dose treatment is also the least costly no definite conclusion regarding cost-effectiveness can be drawn at this stage since survival data is not yet available.