Breast Cancer Prevention at a Young Age: The LEGACY Girls Study.
Esther M. John, PhD, Cancer Prevention Institute of California
Studies attempting to identify breast cancer risk factors have focused mainly on genetics and lifestyle in adult women. However, there is growing evidence that young girls may be particularly sensitive to exposures (e.g., ionizing radiation exposure, childhood and adolescent growth, body composition, and physical activity) that are associated with either initiation of breast cancer or protection against breast cancer. It has not been studied whether the effects of early-life exposures on breast cancer are greater in individuals with a family history of breast cancer than in those at average risk (individuals without a family history). To study the relation between early-life exposures and endpoints related to pubertal and adolescent development, the LEGACY Girls Study was initiated in 2011 at five centers in the USA and Canada, with the goal of recruiting 950 girls aged 6-13 years and their mother or guardian for a 5-year prospective follow-up study. Importantly, half of the girls will have a family history of breast cancer and are therefore at increased risk of developing breast cancer in adulthood. The girls with a family history are the offspring of women enrolled in the Breast Cancer Family Registry (BCFR), and the girls without a family history are being recruited through community outreach and other approaches. The girls will be followed prospectively with repeated data and biospecimen collection at 6-month intervals, to study childhood exposures in relation to pubertal development, age at menarche, breast tissue characteristics, selected biomarkers and markers of epigenetic changes, and the psychosocial impact of increased breast cancer susceptibility. The LEGACY Girls Study, conducted by an interdisciplinary team of scientists, will provide novel information that is crucial to understanding when breast cancer susceptibility begins, whether it is influenced by modifiable determinants in early life, and how a family history of breast cancer affects psychosocial adjustment and behaviors throughout childhood and adolescence.