Abstract Background: The prognosis for patients with metastatic breast cancer (MBC) has substantially improved due to advancement in therapies. With prolonged survival, patients’ caregivers often experience an extended duration of caregiving. However, little is known about the impact of a MBC diagnosis and treatment on caregivers, or on the caregiver-patient relationship over time. Using a dyadic approach, this study explored how patients with MBC and their caregivers perceive a MBC diagnosis and subsequent caregiving needs over time on an individual and dyadic level. Methods: Patient-caregiver dyads participated in semi-structured qualitative interviews from July 2024-March 2025. Informal caregiver was defined as an unpaid individual who provides at least 50% of a patient’s care needs. Patients and caregivers were interviewed separately. The interview guide included questions about patient and caregiver perspectives on and experiences with MBC diagnosis and treatment, unmet needs, and facilitators and barriers associated with caregiving. Interviews were audio-recorded and transcribed; transcripts were imported into the qualitative data management program MAXQDA and analyzed using an adapted framework method. Results: Eleven patient-caregiver dyads consisting of opposite sex-spouse pairs (n = 7), same-sex spouse pair (n = 1), opposite-sex engaged pair (n =1), and daughter-mother pairs (n=2) were interviewed. In relating participants’ experiences, four themes were developed: 1) contrast of a prior cancer diagnosis to current MBC experience, 2) concerns related to individual health after MBC diagnosis and its role in caregiving needs, 3) MBC as a shared diagnosis and experience, and 4) impact of MBC diagnosis on the dyadic relationship. Participants contrasted MBC with patients’ previous cancer diagnoses, which typically included a shorter, intense period of treatment followed by a return to normalcy. Conversely, for MBC, participants highlighted the uncertainty of the survival period, prolonged symptoms, and the realization that there would be no return to normalcy. Both patients and caregivers shared concerns about the impact of MBC on their individual health and its impact on the dyad. While patients focused on feelings of uncertainty regarding their own functioning, mortality and potential increase in caregiving needs over time, caregivers shared concerns about their health, age, and ability to provide a prolonged duration of caregiving. Caregivers often viewed MBC diagnosis/treatment as a shared experience, frequently using “we” or “our” in responses. An important topic was the impact of a MBC diagnosis and treatment on their shared activities as a dyad (i.e. socializing, traveling, and exercising together). Patients emphasized that caregivers needed time for hobbies and self-care, but caregivers were frequently concerned about leaving patients alone or traveling far. In terms of the dyadic relationship, both patients and caregivers described monitoring and managing the others’ emotions. Most participants agreed that the MBC diagnosis either hadn’t affected their relationship or had brought them closer. Conclusions: Caregiving changes clinical interpersonal dynamics by bringing an additional person into the clinical relationship. Given this, dyadic approaches are particularly useful as they provide insight into the unique perspectives and experiences of each dyad member and their influence on interpersonal processes. Understanding patient and caregiver perspectives and experiences of MBC diagnosis, treatment, and caregiving needs from both an individual and a dyadic perspective is essential to improving clinical care and quality of life for patients with MBC and their caregivers. Citation Format: N. M. Fleege, E. E. Chasco, L. Soweid, S. Houghton, A. T. Seaman. “We’Re both dealing with the same thing, but on different sides of it” - understanding metastatic breast cancer through a dyadic lens: a qualitative assessment of patient and caregiver perspectives and experiences abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-04-03.
Fleege et al. (Tue,) studied this question.