The purpose of this study is to develop and test a new intervention to reduce depressive symptoms in post-treatment cancer participants.

Mindfulness-based interventions (MBIs), including Mindfulness-based Cognitive Therapy (MBCT), reduce depressive symptoms in medically ill populations, including cancer survivors. However, MBIs have limitations, and if improved, could dramatically increase their clinical reach and impact. Most standardized MBIs are group-based, time intensive, difficult to scale, and can be costly. Thus, only a small portion of patients ever engage with MBIs. Digital approaches to delivering mindfulness content (apps and brief MBIs) have shown promise for addressing these barriers to accessibility and scalability. However, these digital approaches are not typically tailored for people with medical illness, like cancer, and/or have poor adherence. Mindfulness app user engagement decreases by 90% within 7 days of download, and the average total use of the app is only 16-21 minutes. Moreover, a recent review of MBIs that included standardized group-based MBIs (e.g., Mindfulness-Based Stress Reduction [MBSR]) and three mindfulness-based apps (e.g., Calm) estimated a 40-60% adherence rate of assigned at-home practice (30-45 minutes/day) in cancer survivors during the MBI, which further declines post-intervention. This suggests that the currently prescribed daily practice dosages are not feasible or accepted by this population. Thus, a brief MBI that optimizes the accessibility and scalability and other benefits of digital and asynchronous delivery, in a feasible and acceptable format, is critically needed for people with depressive symptoms and medical illness.

MBCT, adapted into a brief, daily and digitally delivered format, could increase access, scalability, acceptability, and adherence. While consistent practice for longer sessions yields the most benefit,21 studies have shown improved mood following 5 and 13 minutes of daily meditation for 2 and 8 weeks, respectively. Further, because creating and sustaining a new behavior, like daily meditation, requires consistent repetition, it is plausible that delivering content in short, digestible segments each day, as opposed to longer, weekly sessions, could improve adherence and sustain engagement. The full-length, 8-week MBCT protocol delivered digitally reduces depressive symptoms in cancer survivors, and the standardized 8-week MBCT protocol has already been abbreviated from 2- to 1-hour weekly groups (MBCT-Brief). When tested via remote delivery (telephone), MBCT-Brief showed a decrease in depressive symptoms in participants with medical illness (i.e., hypertension). Because of its abbreviated format and evidence for reducing depressive symptoms in people with medical illness, MBCT-Brief is a logical and feasible intervention to adapt into a daily text-delivered format for depressive symptoms in post-treatment cancer survivors.

Inclusion Criteria:

1. Self-reported mild to moderately-severe symptoms of depression (score 5-19 on PHQ-9).
2. A diagnosis of stage 0-III breast, prostate, or colorectal cancer.
3. Completion of primary cancer treatment within 2 years (excludes hormone therapy).
4. An ability to provide informed consent.
5. An ability to read and speak English.
6. Access to a web-enabled device (phone, tablet, computer).

Exclusion Criteria:

1. Self-reported minimal and severe depressive symptoms (<4 and > 20 on PHQ-9).
2. Self-reported suicidal ideation (>1 on item 9 PHQ-9).
3. Another psychological, medical, or other condition/issue determined that necessitates priority treatment and/or that would interfere with participation (e.g., schizophrenia, borderline personality disorder)
4. Current or recent substance abuse/dependence.
5. Stage IV cancer diagnosis.
6. A cancer recurrence actively requiring treatment.
7. Self-reported active mindfulness practice.
8. Prior participation in a formal mindfulness program (e.g., MBCT, Mindfulness-Based Stress Reduction Program, Mindfulness-Based Cancer Recovery

After the completion of the study and the associated publication, we will deposit de-identified data and metadata (i.e., codebook, focus group interview guides, protocols) that are necessary for or of sufficient quality to validate and replicate the research findings in the Open Science Framework repository (https://osf.io/).

Data will become available after the completion of the study and the associated publication and will remain available indefinitely.