ESR1 and breast carcinoma: One recent meta-analysis with individual data on 31,920 postmenopausal women with estrogen receptor positive (ER+) early breast cancer found the 10-year recurrence risks for 5 years of AIs and 2–3 years of tamoxifen and then AIs were 3.6% (95% confidence interval [CI]: 1.7–5.4%, p<0.00001) and 2.0% (95% CI: 0.2–3.8%, p=0.0001) lower than 5 years of tamoxifen, respectively [5].