ESR1 and ductal breast carcinoma in situ: The criteria for defining low-risk DCIS were the same as in the COMET (Comparison of Operative versus Monitoring and Endocrine Therapy) trial, including 40 years of age or older, low/intermediate DCIS without IBC diagnosed on CNB, ER(+) and/or PR(+), HER2(−) and no mass on physical examination or imaging [28].