Episodic future thinking: A behavioral intervention to promote weight loss in breast cancer survivors.

TPS12139 Background: Obesity at diagnosis is associated with an increase in breast cancer (BC) specific mortality. Behavioral interventions targeting obesity-related health choices offer a scalable approach to improve patient engagement in the community. Episodic Future Thinking (EFT) is a novel remotely delivered behavioral intervention which engages the science of prospection where participants mentally simulate positive, detailed, and personal events that can occur in the future. EFT targets a key behavioral economic measure – Delay Discounting (DD). As DD rate rises, an individual devalues future outcomes to a greater degree and has a higher bias for immediate gratification. EFT can decrease DD in obese patients, leading to improved diet quality and weight loss. However, valuation of the future may impact cancer survivors differently. Herein, we propose the first randomized Phase II trial evaluating adherence and changes in DD and body weight with 12-week remotely delivered EFT vs control in overweight or obese BC survivors. Methods: Eligible patients have a history of DCIS or stage 1 to 3 BC, BMI > 25 kg/m 2 , have completed surgery, radiation, and chemotherapy, and are motivated to lose weight. They are randomized 1:1 to a 12-week EFT intervention or control (Episodic Recent Thinking; ERT). ERT is a validated control in which patients imagine events in the recent past. Randomization will be stratified by baseline DD rate. There is an optional 12 week follow up period where patients can continue to receive EFT or ERT cues. DD will be measured at baseline and every 4 weeks for 24 weeks. The primary endpoint is adherence, measured by percentage of thrice daily smartphone prompts participants open and attend to during the 12-week trial. Secondary endpoints are changes in body weight and DD rate at 12 and 24 weeks and change in PROs (PROMIS scales), insulin resistance (HOMA-IR), hs-CRP, and diet quality (HEI 2015) at 12 weeks from baseline. With 20 subjects per arm, the study has 80% power to detect deviation of 14 points from a target adherence rate of 80% using a 1 sample t-test. The primary endpoint is evaluable for all subjects, regardless of drop-out. Secondary endpoints will be evaluated using a linear mixed effects model. Hypothesis tests and confidence intervals will be two-sided at 5% significance/95% confidence level. Since trial activation in November 2021, 9 of the planned 46 patients are enrolled. Accrual is closely integrated with the dedicated Ohio State University Comprehensive Cancer Center Survivorship Program. This work is supported by the Alliance Cancer Control Program Pilot Award (5UG1CA189823-08). Clinical trial information: NCT05012176.