Designing a translational epidemiologic study: Chloroquine and breast cancer chemoprevention in Returned Peace Corps Volunteers

We present the design of a novel translational epidemiologic approach to confirm preclinical data on the chemopreventive potential of a well-characterized anti-malarial drug. BACKGROUND: Exposure to chloroquine, an off-patent anti-malarial drug with a 60-year history of use by millions, reduces the incidence of breast cancer in genetically programmed rats by 37%. OBJECTIVE: A multidisciplinary team of breast-cancer epidemiologists, biostatisticians, a social scientist, and a clinician-researcher designed an epidemiologic study to evaluate the effect of chloroquine on breast cancer incidence in humans. The challenge was to design a study that could quickly and cost-effectively test chloroquine's effectiveness against breast cancer in humans. METHODS: Peace Corps volunteers who served in malaria-endemic areas received chloroquine prophylactically. Therefore, we plan to recruit returned volunteers who served between 1961 and 1990 through the National Peace Corps Association and social media. We will characterize participants into exposed and unexposed groups, based on country of service. Since breast cancer is a complex disease affected by family history, race, and lifestyle, the online survey will elicit self-reported data on potential confounding variables which will be accounted for in the statistical analysis to maximize internal validity. Finally, we will account for cohort members who died of breast cancer or other causes by incorporating National Death Index data. DISCUSSION: Although this is a retrospective epidemiology study design, the gain in cost and time efficiencies provides an excellent approach to translating preclinical data on breast cancer chemoprevention into the public health arena and potentially promoting the repositioning of a well-characterized and relatively benign drug.