Automated breast tissue measurement of women at increased risk of breast cancer

We have analysed data from a subgroup of thirty-nine women who had previously gained more than 10kg in adult life, and who were amongst those recruited from a family history clinic to a study examining the effects of diet and exercise on breast cancer risk. At entry to the study and after 12 months they underwent a series of investigations, including mammography during which markers were attached to the compression plate to allow accurate measurement of breast thickness. A calibrated stepwedge was placed adjacent to the breast to enable quantitative analysis. The proportions of glandular and fatty tissue were calculated at each pixel from the stepwedge and thickness data and from these, the percentage gland in the breast was computed, both by area and by volume. Statistical analysis showed that the volume of glandular tissue was not related to breast size. Over the 12 month period, the majority of the women lost weight, while some gained weight. It was found that weight change was correlated with change in the volume of fat in the breasts, with those women who lost the largest amount of weight showing the greatest reduction in volume. There was little change in volume of glandular tissue for any of the women. Percentage gland is often used as an indication of risk of developing breast cancer. These results suggest that measures of percentage of gland (e.g. Boyd groups) may be dominated by excess breast fat in overweight women.