Globally, breast cancer is the most common cause of cancer death among women. The most common pathological subtype is hormone receptor positive breast cancer, which accounts for approximately 70% of all diagnoses. Adherence to adjuvant hormone therapy (HT), including selective estrogen receptor modulators and aromatase inhibitors, in the treatment of hormone responsive breast cancer decreases risk of recurrence and increases overall survival among women. Unfortunately, up to half of patients discontinue HT prematurely or administer HT less frequently than prescribed, which increases risk of disease recurrence and associated mortality. Understanding the mechanisms underlying nonadherence will allow for development of targeted interventions to improve breast cancer survival.

A defining characteristic of adjuvant HT is that it provides no short-term benefits and, instead, prevents disease recurrence only after years of sustained adherence. In contrast, the benefits of discontinuing HT are relatively immediate (e.g., avoidance of adverse side effects, such as hot flashes or arthralgia). Thus, adherence to HT requires one's behavior to be guided by temporally distant outcomes, as bias toward immediate gratification narrows the temporal window over which future costs and benefits can motivate behavior. Therefore, treatment adherence may be understood through the behavioral economic process of delay discounting (i.e. devaluation of delayed outcomes), which provides a measure of how individuals value the future. Accumulating evidence shows that delay discounting is associated with a wide variety of maladaptive health behaviors, including failure to seek routine medical screening for cancer and other illnesses. However, no work has yet examined associations between delay discounting and adherence to cancer treatment, generally, or breast cancer treatment, specifically. This gap in knowledge represents a challenge to the understanding of risk factors for cancer-related morbidity and mortality and may limit the efficacy of breast cancer treatment.

Accordingly, the present study will investigate the acute efficacy of an episodic future thinking (EFT) intervention for reducing discounting and improving valuation of future health in breast cancer patients. EFT is a form of prospection that involves mental simulation of events that might occur in one's future. To some extent, EFT is an innate human ability that guides decision-making (e.g., simulating the experience of an upcoming job interview or social event); however, populations who discount the future rapidly show deficits in this ability, considering the future infrequently and demonstrating low-quality EFT content (e.g., fewer contextual and sensory details). Thus, EFT interventions are designed to remediate this deficit and reduce bias toward immediate gratification by guiding individuals to both generate high-quality EFT content and prompting them to engage in EFT frequently. Prior laboratory-based research by the investigative team and others has shown that EFT both reduces delay discounting and improves a wide range of maladaptive health behaviors and outcomes contributing to the development of cancer and survival following diagnosis and treatment, including tobacco use and dietary and weight control. The present study seeks to extend these findings by demonstrating that EFT improves laboratory-based measures of delay discounting and valuation of future health in breast cancer patients. Demonstrating EFT's acute efficacy in the laboratory would suggest that EFT may be adapted in future grant proposals as a targeted, remotely delivered intervention to improve HT adherence and subsequent breast cancer survival.