Estimation of loss of quality-adjusted life expectancy (QALE) for patients with operable versus inoperable lung cancer: adjusting quality-of-life and lead-time bias for utility of surgery

Abstract

Objectives: This study attempts to quantify the difference in loss of quality-adjusted life expectancy (QALE) for patients with operable and inoperable non-small-cell lung cancer (NSCLC).

Patients and methods: A cohort consisting of 1652 pathologically verified NSCLC patients with performance status 0-1 was monitored for 7 years (2005-2011) to obtain the survival function. This was further extrapolated to lifetime, based on the survival ratios between patients and age- and sex-matched referents simulated from the life tables of the National Vital Statistics of Taiwan. Between 2011 and 2012, EuroQol 5-dimension questionnaires were used to prospectively measure the quality-of-life (QoL) of a 518 consecutive, cross-sectional subsample. We adjusted the lifetime survival function by the utility values of QoL for the cancer cohort to obtain the QALE, while that for the age and sex-matched referents were adjusted to the values collected from the 2009 National Health Interview Survey, and the difference between them was the loss-of-QALE.

Results: The QALE for patients with operable and inoperable NSCLC were 11.66±0.18 and 1.43±0.05 quality-adjusted life year (QALY), with the corresponding loss-of-QALE of 5.25±0.18 and 14.24±0.05 QALY, respectively. The lifetime utility difference for patients with operable and inoperable NSCLC was 9.00±0.18 QALY, after adjustment for QoL and lead-time bias.

Conclusion: The utility gained from surgical operation for operable lung cancer is substantial, even after adjustment for lead-time bias. Future studies should compare screening programs with treatment strategies when carrying out cost-utility assessments to improve patients' values.

Keywords: Lead-time bias; Lung cancer surgery; Quality-adjusted life expectancy; Quality-adjusted life year; Quality-of-life; Utility.