Distance to Mammography Facilities and Breast Cancer Screening: A GIS Approach

Objectives: The objective of the study was to examine whether geographic proximity to mammography facilities influences utilization of mammography. Methods: Data was obtained from Colorado (CMAP) on female breast carcinoma cases from 1999-2001. Distance to mammography facilities was measured by using GIS. First, a straight-line distance was measured with ZipFind Deluxe 5.0 software between the centroids of women's residence Zip code and mammography facility Zip code; second, Floating Catchment Area (FCA) Method considering all available facilities within an arbitrary radius from the woman's residence by using Arc GIS 9.0 software measured access to mammography facilities. Results: Of 2,024 women 91.4% were Caucasian; age ranged from 25 to 98 years; most (95%) were non-Hispanic in origin. Logistic regression found age, family history, hormone replacement therapy, physician recommendation, and breast cancer stage at diagnosis to be significant predictors of having had a previous mammogram in both models (distance measure and access measure). Women having higher access to mammography facilities were less likely to have had a previous mammogram compared to women who had low access, considering all the facilities within 10 miles (OR=0.41, CI=0.22-0.76), 30 miles (OR=0.52, CI=0.29-0.91) and 40 miles (OR=0.51, CI=0.28-0.92) radiuses. Conclusions: Physical distance to mammography facilities does not necessarily predict utilization of mammogram and greater access does not assure greater utilizations, due to constraints imposed by socio economic and cultural barriers. Future studies should focus on measuring access to mammography facilities capturing a broader dimension of access considering qualitative aspect of facilities, as well as other travel impedances.