JMIR Publications

ABSTRACT

Background:

Health-related Quality of Life (HRQoL) is used to evaluate the treatment of metastatic breast cancer. In a long-term therapy setting HRQoL can be used as an important benchmark for treatment success. With the help of digital applications HRQoL monitoring can be extended to more remote areas and be administered on a more frequent basis.

Objective:

This study aims to examine the longitudinal development of HRQoL data using the time to deterioration (TTD) in three different questionnaires in a digital web-based setting.

Methods:

192 patients with metastatic breast cancer were analyzed in this bicentric prospective online cohort study at two German university hospitals. Patients completed questionnaires on HRQoL (EQ-VAS, EQ-5D-5L, EORTC QLQ-C30) via an online platform over a six-month period. Treatment schedules and medical history were retrieved from medical records. Cox-regression analysis on treatment-related factors was performed. We conducted subgroup analyses in regard to TTD events between different treatments.

Results:

The EQ-VAS showed a higher rate of deterioration after eight weeks (47%) than the EQ-5D-5L (29%) and the EORTC QLQ-C30 (37%). Cox regression revealed a higher risk for shortened TTD in the EQ-VAS for patients with progressive in comparison to stable disease (hazard ratio (HR) =1.48, P=.11). Significant correlations between EQ-VAS events and single EQ-5D-5L items and the EQ-5D-5L summary score were demonstrated. All treatment groups significantly differed from the CDK4/6-inhibition subgroup in the EQ-VAS.

Conclusions:

Compared to the EQ-5D-5L and the QLQ-C30, the EQ-VAS showed a higher rate of deterioration after eight weeks. A discrimination between progressive and stable disease and correlations between deterioration and certain metastatic locations were only detected in the EQ-VAS. TTD with the EQ-VAS is an adequate mean of examining longitudinal development of HRQoL among breast cancer patients.