Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Mutation identification via circulating tumor DNA (ctDNA) to select appropriate therapy has demonstrated clinical utility in metastatic breast cancer (MBC). SERENA-6 demonstrated the efficacy and tolerability of camizestrant in HR + /HER2-, ESR-1 mutated MBC after an AI/CDK 4/6 inhibitor. However, it remains unclear whether switching therapy at the time of ctDNA-detected emergence of ESR-1 mutations (“molecular progression”) improves long-term outcomes over switching therapy at the time of traditional anatomic/clinical progression.