The Sister Study: Genetic and Environmental Risk Factors for Breast Cancer
The Sister Study seeks to evaluate the role of gene-environment interactions in breast cancer risk. Social & Scientific Systems is enrolling a volunteer cohort of 50,000 sisters of diagnosed breast cancer cases and following them for a period of 10 years. Working closely with NIEHS epidemiologists, we had a major role in the design and planning for this large and complex study. Since cancer-free sisters of women who have had breast cancer are at increased risk, the cohort is designed to be large enough to have sufficient cases for examination of various gene-environment interactions after 5 years. The interview includes questions on established breast cancer risk factors as well as questions related to new hypotheses. Field examiners collect biological and environmental samples; take anthropometric measurements of height, weight, hips, and waist; and measure blood pressure and pulse.
We conducted a pilot study of 2,000 women to test the effectiveness of various recruitment and eligibility screening methods as well as the procedures for interviewing and biologic specimen collection. In the fall of 2004, we began data collection for the main study. We are conducting a nationwide campaign involving a combination of recruitment strategies to enroll the cohort, with special attention to the recruiting of minority and elderly women. Interested women can complete the eligibility screening process on the Web or by telephone. After formal enrollment, each eligible woman is sent an enrollment kit that includes four self-administered questionnaires and materials with instructions for collecting the samples. We contact each participant to explain the contents of the kit and to arrange the interview. We conduct two separate 1-hour CATIs with each participant. A field examiner/phlebotomist visits the participant's home to draw blood, take measurements, and collect the other biological and environmental specimens. The examiner then ships the materials to our laboratory, where they are aliquoted and processed to prepare them for long-term storage at an NIEHS specimen repository. Annual self-administered mail questionnaires on current health status and other information are being collected. As the incidence of breast cancer is ascertained prospectively, we will seek medical records, an additional blood sample, and tumor tissue to augment assessment of biological data for nested case-control analysis of the sisters who develop breast cancer and a sample of those sisters who do not. We will also contact medical providers and places of treatment in an effort to collect detailed diagnostic and treatment data.
Click here for a more detailed, printable description of the Sister Study (PDF).