Specific Aim 1: Determine the effect of CASA on psychological distress (primary outcome) and on neuroendocrine, inflammatory, and translational control measures (secondary and exploratory outcomes) in LSBC-PR patients and caregivers. We will conduct a two-arm randomized controlled trial of 70 patient caregiver dyads (35 per arm; N=140 individuals) comparing CASA to usual care, with assessments at baseline (T1) and post-intervention (T2, 5 to 10 weeks). This sample provides 80% power (a=0.05, two-tailed) to detect d=0.80 on the primary outcome, consistent with ORBIT Phase 3 signal confirmation. Psychological distress (Distress Thermometer) is the primary outcome and depressive symptoms (PHQ-8) the secondary psychosocial outcome; patients are the primary analytic unit, with caregivers analyzed in parallel. Plasma cortisol is the key secondary biological outcome; inflammatory cytokines (IL-6, TNF-a, IL-1B, IFN-v, IFN-a, IP-10, CRP) are secondary biological outcomes tested with Benjamin Hochberg FDR control; polysome profiling of PBMCs (with Dr. Dharmawardhane, UPR-MSC) is exploratory. Outcomes are tested hierarchically to control family-wise error. Recruitment, intervention delivery, and biospecimen collection will be conducted at the Puerto Rico Biobank (PRBB) under PMSF-PRI IRB oversight, leveraging Alliance partner collaboration (UPR-MSC and PMSF-PRI). Expected Outcome: CASA will produce greater reductions in psychological distress than usual care, with signals in cortisol and inflammatory cytokines that inform a fully powered R01 to confirm stress-biology mechanisms in LSBC-PR dyads.
Specific Aim 2: Develop and validate a multilevel implementation strategy for CASA informed by implementation science determinants and stakeholder co-design. Using mixed methods, Consolidated Framework for Implementation Research (CFIR) guided semi-structured interviews (n=20) with oncology and clinic-based stakeholders will be supplemented by validated measures of acceptability, feasibility, and appropriateness. Determinants will be mapped to Expert Recommendations for Implementing Change (ERIC) strategies; co-design sessions will produce a context-specific implementation blueprint. Expected Outcome: A stakeholder-validated implementation strategy that identifies key determinants of CASA uptake and provides an actionable roadmap for scalable delivery across Puerto Rican oncology settings.