”Big-breasted women” have a higher risk of breast cancer U.S. scientists have completed a study on breast size and the chance of breast cancer. The study was conducted on 89,268 women between the ages of 29 and 47, whose breast size was measured at the age of 20, and then they were followed for a long time to understand the relationship between breast size and the occurrence of breast cancer. The results of the study showed that women with large breasts had an 80 percent higher risk of breast cancer compared to women with small breasts. The researchers explained this by the simple fact that the larger the breasts, the more cells there are in the breast. The more cells there are, the greater the risk of potential cell mutation or malignant development.