This study focused on geographic clustering of breast cancer on residence in early life and identified spatio-temporal clustering of cases and controls.  There is growing evidence that early life exposures may be of significance in the etiology (causes of a particular disease) of breast cancer. 

While there have been studies of breast cancer clusters on current addresses, there have been no such evaluation of clustering of early life residence. Since clustering of breast cancer in space and time may be indicative of potential interaction between environmental exposures and the subsequent risk of breast cancer this study adapted a novel approach: Geographic Information Systems (GIS) and spatial analysis methods, to identify geographic clustering of residences in early life.

This study focused on a case-controlled study of Western New York.  Data was drawn from the WEB study (Western New York Exposures and Breast Cancer Study).Cases were women age 35-79 with incident, primary pathologically confirmed breast cancer diagnosed in Erie and Niagara counties during the years 1996-2001. Controls were frequency-matched to cases on age, race and county of residence. All cases and controls used in the study provided lifetime residential histories.

We found evidence for clustered residence at birth and at menarche was stronger than that for first birth or other time periods in adult life (figure 1). Residences for premenopausal cases were more clustered than for controls at the time of birth and menarche (figure 2).

This study provides evidence that early environmental exposures maybe related to breast cancer risk, especially for pre-menopausal women.

Figure One

Figure Two