BackgroundUp to half of adults with advanced cancer report anxiety or depression symptoms, which can cause avoidance of future planning. We present a study protocol for an innovative, remotely-delivered, acceptance-based, multi-modal palliative care intervention that addresses advance care planning (ACP) and unmet psychological needs commonly experienced by adults with metastatic cancer.MethodsA two-armed, prospective randomized controlled trial (RCT) randomizes 240 adults with Stage IV (and select Stage III) solid tumor cancer who report moderate to high anxiety or depression symptoms to either the multi-modal intervention or usual care. The intervention comprises five weekly two-hour group sessions (plus a booster session one month later) delivered via video conferencing, with online self-paced modules and check-ins completed between the group sessions. Intervention content is based on Acceptance and Commitment Therapy (ACT), an acceptance, mindfulness, and values-based model. Participants are recruited from a network of community cancer care clinics, with group sessions led by the network’s oncology clinical social workers. Participants are assessed at baseline, mid-intervention, post-intervention, and 2-month follow-up. The primary outcome is ACP completion; secondary outcomes include anxiety and depression symptoms, fear of dying, and sense of life meaning. Relationships between anxiety/depression symptoms and ACP will be evaluated cross-sectionally and longitudinally and theory-based putative mediators will be examined.DiscussionAmong adults with advanced cancer in community oncology settings, this RCT will provide evidence regarding the efficacy of the group ACT intervention on ACP and psychosocial outcomes as well as examine the relationship between ACP and anxiety/ depression symptoms. This trial aims to advance palliative care science and inform clinical practice.Trial RegistrationClinicaltrials.gov NCT04773639 on February 26, 2021.