What is breast attenuation?

From the Guidelines

Breast attenuation in the context of breast cancer screening is not directly addressed in the provided evidence, but the importance of accurate imaging in breast cancer detection is emphasized, particularly in high-risk women or those with dense breast tissue. When considering breast attenuation in the broader context of medical imaging, it's crucial to recognize that breast tissue can interfere with the accuracy of imaging studies, potentially leading to false positives or negatives. In the context of breast cancer screening, as discussed in the study by 1, the focus is on the effectiveness of mammography in reducing breast cancer mortality, with annual screening mammography for women 40 to 84 years of age decreasing mortality by 40%. However, the study also notes that dense breast tissue decreases the sensitivity of mammography, highlighting a challenge in breast cancer screening that could be related to breast attenuation. Techniques to improve imaging accuracy, such as prone positioning, using both supine and prone views, attenuation correction software, and selecting appropriate tracers, are not directly mentioned in the provided evidence but are relevant in the broader discussion of minimizing artifacts in medical imaging. Given the emphasis on early detection and the potential for breast attenuation to affect imaging accuracy, clinicians should be aware of the factors that influence image quality and consider supplemental screening modalities for women at high risk or with dense breast tissue, as suggested by the study 1. The use of mammography in combination with MRI for high-risk women is highlighted, showing the highest sensitivity across high-risk groups of women. Ultimately, the goal is to minimize the impact of breast attenuation and other factors on imaging accuracy to ensure timely and accurate diagnosis of breast cancer, thereby reducing morbidity, mortality, and improving quality of life.

From the Research

Breast Attenuation

• Breast attenuation refers to the reduction in breast density, which can be an indicator of the effectiveness of certain treatments, such as tamoxifen, in preventing or treating breast cancer 2, 3, 4, 5.
• Studies have shown that a decrease in breast density due to tamoxifen therapy might indicate a greater benefit from the drug 2.
• Tamoxifen has been found to reduce mean breast density in the first year of treatment, with further decreases in subsequent years 2, 3.
• The reduction in breast density has been associated with a lower risk of breast cancer recurrence and mortality 5.

Measurement of Breast Density

• Breast density can be measured using various methods, including mammography, ultrasound tomography, and automated breast ultrasound 2, 6, 4.
• Mammographic density is a widely used measure of breast density, but it has limitations, such as being affected by the density of the surrounding tissue 6.
• Ultrasound tomography has been found to be a useful tool for measuring breast density and detecting changes in density over time 4.

Factors Affecting Breast Density

• Breast density can be affected by various factors, including age, menopausal status, and body mass index 2, 3.
• Premenopausal women have been found to have a greater reduction in breast density in response to tamoxifen therapy compared to postmenopausal women 3, 4.
• The reduction in breast density has been found to be greater in women with higher baseline breast density 4.