"The highest decision-making level" - Multidisciplinary team meetings as boundary spaces.

Multidisciplinary team meetings (MDMs), also known as tumor boards, play a crucial role in collaborative decision-making within Western healthcare systems. This study explores the significance of MDMs in Danish cancer care through an ethnographic lens, based on fieldwork conducted at five university hospitals. Clinicians regard these meetings as fostering efficiency, reflexivity, consistency, transparency, and security in patient care, and recognize MDMs as "the highest decision-making level" in cancer care. Analytically, we conceptualize MDMs as boundary spaces where professionals engage in collaborative boundary work across disciplines. We introduce a typology of this work-calibrating, reflecting, and guarding-which are conducted before, during, and in relation to MDMs. Our analysis demonstrates how these practices afford relational agency as an enhanced form of individual agency. At the same time, we uncover how these practices establish "gate mechanisms" that privilege certain voices, knowledge, and expertise within the boundary space. This reconfigures professional identities and power dynamics, shaping a specific treatment and care regime as decisions are collectively made by a confined group of clinical actors.