ESR1 and breast cancer: Another ongoing phase III open-label study, the CAMBRIA-1 clinical trial (NCT05774951) (Study Details A Study of Camizestrant in ER+/HER2- Early Breast Cancer After at Least 2 Years of Standard Adjuvant Endocrine Therapy ClinicalTrials.gov, 2023), is evaluating whether camizestrant improves therapeutic effects compared with standard adjuvant endocrine therapy in patients with ER+/HER2-early breast cancer who are at intermediate-to-high or high risk for disease recurrence.