Assessing breast tissue density by transillumination breast spectroscopy (TIBS): an intermediate indicator of cancer risk

Abstract

Risk assessment by parenchymal density pattern, a strong physical indicator of future breast cancer risk, is available with the onset of mammographic screening programmes. However, due to the use of ionizing radiation, mammography is not recommended for use in younger women, thereby rendering risk assessment unattainable at an earlier age. Visible and near infrared light was used on 292 women with radiologically normal mammograms to determine whether transillumination breast spectroscopy (TIBS) can identify women with a high parenchymal density pattern as an intermediate indicator of breast cancer risk. Principal component analysis (PCA) was used to reduce the spectral data and generate density scores for each woman. To assess the accuracy of TIBS, logistic regression was used to calculate crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) for each score. Receiver operator characteristic (ROC) curves and area under the curve (AUC) were also calculated for the crude and adjusted logistic models. Optical information relating to tissue chromophores, such as water, lipid and haemoglobin content, was sufficient to identify women with high parenchymal density. The resulting AUC for the final and most parsimonious multivariate logistic model was 0.922 (95% CI 0.878-0.967). TIBS provides information correlating to high parenchymal density and is a promising tool for risk assessment, particularly for younger women.

Association between Transillumination Breast Spectroscopy and Quantitative Mammographic Features of the Breast

“…In a previous cross-sectional study of 292 women without radiologically suspicious lesions, we showed that TiBS scores (that is, t scores) derived from principal component analysis were highly associated with categorical mammographic density as assessed by a radiologist (23). In this article, we report on the association between TiBS scores and quantitative mammographic features of the breast (percent density, dense area, and nondense area) obtained from analogue films from 104 premenopausal and 121 postmenopausal women from the same cross-sectional study.…”

“…The instrumentation used to gather transillumination spectra was described previously in detail and is depicted in Fig. 1 (20)(21)(22)(23). A 50 W halogen lamp served as broadband light source; 200 mW light of wavelength 550 to <1,300 E was coupled into a 5-mm-diameter liquid light guide (Fibre Guide) placed in contact with the skin on top of the breast with minimal compression.…”

“…Measurements were taken in the dark, with the participant seated comfortably in an upright position and the breast resting on the support platform. For each woman, TiBS measurements were executed in four standardized positions (center, medial, distal, and lateral) on each breast in cranial caudal view, providing optical interrogation of different anatomical regions (20)(21)(22)(23). The center position was in the midline closest to the sternum, the distal position was 2 cm posterior to the nipple, and the medial and lateral positions were 2 cm in from the border of the breast adjacent to the sternum and axilla, respectively.…”

“…Visible light and near-infrared radiation-based transillumination breast spectroscopy (TiBS) is an inexpensive nonimaging, noninvasive technique that provides information about bulk breast tissue properties based on the spectral dependence of the probability of a photon to pass through breast tissue (20)(21)(22)(23). Red and near-infrared light can penetrate f7 cm of breast tissue while permitting good-quality spectra carrying information on wavelength-dependent light scattering and absorption by water, lipids, and hemoglobins (oxyhemoglobin and deoxyhemoglobin; refs.…”

Computer aided automatic detection of malignant lesions in diffuse optical mammography

“…Thus far, a few groups applied statistical analysis techniques to multiparameter optical measurements, including applications to arthritic joints, 16 high-risk 17 or high mammographic density 18,19 breast tissue, and to various "endo-scopic" measurements or excised tissues. 20 The data sets employed thus far, however, have limited spatial information and orders of magnitude fewer measurements per subject than, for example, the breast tomograms utilized in the analysis to be presented herein.…”