Abstract
Purpose
The HORSE-BC study previously demonstrated that 2nd-line endocrine therapy (ET) for metastatic breast cancer (MBC) patients with acquired endocrine resistance still provided a clinically meaningful benefit. Herein, we investigated health-related quality of life (HR-QOL) in HORSE-BC.
Methods
MBC patients with acquired endocrine resistance who were scheduled for 2nd-line ET were recruited. HR-QOL was assessed at baseline and 1 and 3 months after initiation of 2nd-line ET. To investigate the minimally important difference (MID) in the Functional Assessment of Cancer Therapy-Endocrine Symptoms (FACT-ES), we evaluated the means and standard deviations (SDs) for the distribution-based method, and differences in the change in HR-QOL for the anchor-based method. We also investigated the association between FACT-ES total scores and clinical benefit.
Results
Overall, 56 patients were enrolled. Of these, 47 were analyzed. When defined as 1/3 SD estimates based on the distribution method, the calculated MID was 5.9. The MIDs of the FACT-ES total scores based on the anchor method were 7.7 for decline and 4.1 for improvement. The proportions of MID decline were 6.1% and 14.7% lower in patients who experienced clinical benefits than in those who did not at 1 month and 3 months, respectively. The respective ratios of MID improvement in patients who experienced clinical benefits were 18.3% and 3.2% higher, respectively; mean change in FACT-ES total score from baseline was improved in patients who experienced clinical benefits.
Conclusion
Maintaining HR-QOL as determined by FACT-ES may be associated with clinical benefits in patients with acquired endocrine-resistant MBC treated with ET.
An Electronic Patient-Reported Outcome Tool for the FACT-B (Functional Assessment of Cancer Therapy-Breast) Questionnaire for Measuring the Health-Related Quality of Life in Patients With Breast Cancer: Reliability Study
