Time to health-related quality of life improvement analysis was developed to enhance evaluation of modern anticancer therapies.

OBJECTIVES: Major advances have recently been made in the treatments of cancer, which now also have the potential to improve patients' health-related quality of life (HRQOL). We propose the time to HRQOL improvement (TTI) and the time to sustained HRQOL improvement (TTSI) as potentially important cancer outcomes to be used in longitudinal HRQOL analyses.

STUDY DESIGN AND SETTING: As proof of principle, we defined TTI and TTSI, using the Fine-Gray model to include competing risks in estimates, in a case study in real life of a cohort of newly diagnosed patients with cancer receiving a targeted therapy. HRQOL was evaluated before and during therapy with six assessments over a 24-month period, using the well-validated European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30.

RESULTS: For each assessed HRQOL domain, we assessed TTI and TTSI and estimated the cumulative incidence of patients' clinically meaningful improvements, also accounting for the occurrence of competing events.

CONCLUSION: TTI and TTSI are potentially important outcomes in the era of modern anticancer therapies. The analysis of TTI and TTSI by competing risks approach will further add to the statistical methods that can be used to inform on the impact of cancer therapies on patients' HRQOL.