Breast cancer is the most commonly occurring cancer in women. The lifetime risk of being diagnosed with breast cancer is approximately 1 in 10 thereby the highest out of all cancers. Breast cancer screening programs have been shown to decrease the mortality rates of women between ages 50-69, since cancers are detected at an earlier, more favourable stage. It is apparent that the development of breast cancer is a slow process following initial transformation of the breast tissue. Hence, there has been a strong effort within the research community to understand risk factors for the disease. Risk factors are defined as those characteristics that are more common in people with the disease when compared to the normal population. Quantification of an individual's breast cancer rate may lead that individual to modify her lifestyle and/or diet. Lifestyle changes could lead to a reduction in the incidence of breast cancer.
Anatomically, the presence of increased amounts of fibroglandular tissue raises the estimated risk by up to 6 fold (correct for age), hence representing one of the strongest known risk factors pertaining to the entire female population. In this study the relative area of mammographic densities within a mammogram will be used as a global risk assessment tool. It has been shown previously that quantification of water, lipids, haemoglobin and other tissue chromophores of the optically interrogated breast tissue, which also gives rise to the mammographic densities, is feasible through near-infrared spectroscopy. Thus, the hypothesis for this study is that optical transillumination spectroscopy provides consistent and/or complementary information to conventional mammography in quantifying breast tissue density.