Correlations between access to mammography and breast cancer stage at diagnosis

There is a lack of data on the access to mammography and its relation to the incidence of early breast cancer. In this study, the authors evaluated access by correlating geographically the number of U.S. Food and Drug Administration (FDA)-certified mammography facilities and the AJCC stage of breast cancer at diagnosis by county.

Breast cancer incidence rates and stage at diagnosis were compared with the number of FDA-certified mammography facilities by county in the Surveillance, Epidemiology, and End Results reporting areas. The objective was to determine whether the number of certified facilities was associated with the percent of breast cancers diagnosed at the in situ stage. This was a multiple-group ecologic study, and counties were used as the units of analysis.

There was a strong correlation between the number of mammography facilities and the population of a county, whereas there was no correlation between the number of mammography facilities and the land area of a county. A correlation existed between the percent of incident breast cancers that were diagnosed as in situ disease and the number of mammography facilities per 10,000 women among both whites and African Americans.

There was an association between the number of mammography facilities and population. In counties with >/= 30,000 black and white females, 1) the percent of in situ breast cancers in black women and white women was correlated with the number of facilities per 10,000 women, indicating that population density is a factor in access for both racial groups; 2) except for 2 counties with >/= 30,000 black women, the percent of incident in situ cases was similar in both black women and white women, indicating equal access in both groups; and 3) there was a correlation between the percent in situ incidence and number of facilities per 1000 square miles in white women, but not in black women. There was a direct correlation of statewide mammography rates with the number of facilities per 1000 square miles, indicating that the rate of screening depends on availability. Maximum rates of statewide screening were achieved when there were > 15 mammography facilities per 1000 square miles.