Cost-utility Analysis of a Supervised Exercise Program for Patients with Metastatic Breast Cancer in the PREFERABLE-EFFECT Randomized Controlled Trial (RCT).

11121 Background: Exercise for patients with metastatic breast cancer (mBC) significantly reduced fatigue and improved quality of life (QoL) in the multinational PREFERABLE-EFFECT RCT (NCT04120298). Evidence on the cost-effectiveness of exercise for patients with mBC is lacking, albeit essential for implementation in clinical practice. In this study, we evaluated the cost-utility of an exercise program for patients with mBC in the EFFECT RCT. Methods: We conducted a cost-utility analysis using data from the 357 EFFECT trial participants (mean age 55 ± 11 yrs, 75% on 1st/2nd line treatment). These participants, from centers in NL, DE, SE, PL, ES, AU, were randomized to either a 9-month supervised exercise intervention (n=178) or a usual care control group (n=179). We used a societal perspective with a time-horizon of 9 months. Two different scenario analyses (SA) were used to determine intervention costs using a bottom-up micro-costing method: SA-1) 1-on-1 supervision; SA-2) 4-on-1 supervision. Data on healthcare resource use, productivity loss and QoL (converted to QALYs) were collected with country-adapted, self-report questionnaires, including the iMCQ, iPCQ and EQ-5D-5L, at 3-, 6- and 9-months post-baseline. Multiple imputation was performed, and bootstrapping was used to study uncertainty. Results: Compared to usual care, supervised exercise led to a QALY gain of 0.015 (95% CI: -0.02; 0.05) over a 9-month period, corresponding to an increase of 5.3 days in perfect health. The mean intervention costs were €1,696 in SA-1 and €609 in SA-2. The mean total cost differences (adjusted for center and line of treatment) were -€27 (SA-1), and -€1,112 (SA-2), in favor of the exercise group ( Table). The greatest cost-savings occurred in hospital costs, meaning that the exercise group had lower hospital costs compared to the control group (€4,430 vs €5,211). The probability of supervised exercise being cost effective at a willingness-to-pay threshold of €20.000 or €80.000 per QALY gained was 62% or 76% in SA-1, and 91% or 92% in SA-2, respectively. Conclusions: Exercise for patients with mBC is likely to be cost-effective when individually supervised and even dominant (greater cost-savings and more effective) when group-based. Based on our positive findings for both effectiveness and cost-effectiveness, we recommend supervised exercise to be reimbursed as supportive care during treatment for mBC. Clinical trial information: NCT04120298 . [Table: see text]