Utility assessment
Outcomes were measured as quality-adjusted life years (QALYs), which is
used to measure a disease burden, including both the effect on life
quality and the quantity of life lived. Life quality is represented by
utility weights given for each health state, ranging from 1 (best
attainable health) to 0 (death). The utility values of the different
health states were based on the study of Venkatesh et
al.3 We considered the utility value of patients with
lrPTMC under AS as 0.88. This represents a disutility difference, e.g.,
lower quality-of-life, of AS compared to disease-free state post-HT,
driven mainly from studies conducted in prostate cancer – another
malignancy that can be treated by active surveillance. We have also
considered a range of 0.88 to 1 in the sensitivity analysis, as utility
of 1 was suggested in other studies.17