ESR1 and complete blood cell count: In the overview analysis, the risk of CBC was 0.4 % per year for estrogen receptor–positive patients and 0.5 % per year for estrogen receptor-negative patients.18 A Surveillance, Epidemiology, and End Results (SEER) study performed nearly 10 years ago showed that CBC risk has been decreasing 3 % per year since 1985 due in part to increased use of hormone therapy.19 Annual risks of CBC are highest in patients younger than 30 years and patients with multiple affected first- and second-degree relatives (annual risk 0.4–1.3 %).