Background <p>Adolescent and young adult cancer survivors (AYACS), aged 15–39, experience higher rates of depressive symptoms (25%–32%) compared to their non-cancer peers or older cancer survivors. While mobile health applications have shown promise in managing physical symptoms, their efficacy in addressing depression in AYACS remains underexplored. This study aims to evaluate the feasibility and acceptability of study procedures for a full factorial trial that will identify the optimal components of a digital tool (ASCENT) designed to promote self-management of depressive symptoms among AYACS.</p> Methods <p>Using a full factorial design, we will randomize 16 AYACS who have completed cancer treatment within the past 5 years to 1 of 16 conditions. The primary outcome for this study is the acceptability of study procedures, evaluated via an investigator-developed acceptability survey. Further, semi-structured exit interviews will be conducted to characterize reasons for aspects of the study with sub-optimal acceptability. Quantitative and qualitative data will also be collected on secondary outcomes including the feasibility of study procedures (as measured by recruitment and retention rates), participant use of and engagement with ASCENT, and participant feedback on ASCENT (e.g., usability, acceptability, and satisfaction).</p> Discussion <p>This pilot trial will assess the acceptability and feasibility of study procedures for a full factorial trial that will optimize a digital tool targeting depressive symptom self-management in AYACS. Findings will inform adjustments to enhance the design and implementation of a fully powered trial.</p> Trial registration <p>This trial was prospectively registered in ClinicalTrials.gov (NCT06420193) on May 17, 2024, <a href="https://clinicaltrials.gov/study/NCT06420193">https://clinicaltrials.gov/study/NCT06420193</a>. All items from the World Health Organization Trial Registration Data Set are listed in the table below.</p>