Oncologists’ experiences of decision-making in later lines of metastatic breast cancer treatment: Balancing between autonomy and authority  With the rapid development of new treatments for metastatic breast cancer, selecting the most appropriate treatment strategy has become increasingly complex. In daily practice, oncologists often encounter clinical situations that are not well represented in clinical trials and where guidelines offer limited direction. The challenge of adequately integrating patients’ preferences adds another layer of complexity. In this study, we aimed to explore oncologists' experiences of making treatment decisions in later lines of treatment in metastatic breast cancer. This qualitative study was conducted with a constructivist approach and utilized individual interviews with twelve oncologists in Sweden. The study participants had 5-40 years of experience in breast cancer care, working in publicly funded healthcare.. Inductive reflexive thematic analysis was applied to identify themes, focusing on both the manifest and latent messages within the data. Results We identified three themes describing the strategies used by oncologists during consultations: Allowing the patient to make the final decision (autonomy), Relying on professional knowledge and experience to decide (authority), and Inviting the patient to a dialogue to decide (alliance). A fourth theme was identified: Turning to colleagues for advice and support (accountability), an action that took place outside the consultation. Participants described how they navigated between these approaches depending on the patients' and their own needs. Making treatment decisions in metastatic breast cancer is a complex and challenging task. This study showed that in situations where clinical guidelines do not offer clear advice, oncologists took on different approaches to decision-making -shaped but how they viewed their role in relation to the patient. We believe that enhanced awareness can support oncologists by easing the burden, fostering more sensitive and insightful interactions with patients, and ultimately improving the quality of decision-making.