Nature Reviews Clinical Oncology, Published online: 03 September 2025; doi:10.1038/s41571-025-01073-3Some of the most consequential conflicts in oncology and medicine overall are not financial; these remain poorly defined and weakly regulated. Here we offer a policy-relevant definition and examine how reputation, ambition, ideology and institutional loyalty can shape research, guidelines, policy and hiring decisions. We argue for structural safeguards to preserve trust in medicine.

Some of the most consequential conflicts in oncology and medicine overall are not financial; these remain poorly defined and weakly regulated. Here we offer a policy-relevant definition and examine ho...