GYN Image Quiz

Which of the following statements about breast density is TRUE?

_{Text copyright DenseBreast-info.org.}

Answer

D. The risks associated with dense breast tissue are 2-fold: Dense tissue can mask cancer on a mammogram, and having dense breasts also increases the risk of developing breast cancer. As breast density increases, the sensitivity of mammography decreases, and the risk of developing breast cancer increases.

A woman’s breast density is usually determined by a radiologist’s visual evaluation of the mammogram. Breast density also can be measured quantitatively by computer software or estimated on computed tomography scan or magnetic resonance imaging. Breast density cannot be determined by the way a breast looks or feels.

Breast density and mammographic sensitivity

Cancers can be hidden or “masked” by dense tissue. On a mammogram, cancer is white. Normal dense tissue also appears white. If a cancer develops in an area of normal dense tissue, it can be harder or sometimes impossible to see it on the mammogram, like trying to see a snowman in a blizzard. As breast density increases, the ability to see cancer on mammography decreases (FIGURE 1).

Standard 2D mammography has been shown to miss about 40% of cancers present in women with extremely dense breasts and 25% of cancers present in women with heterogeneously dense breasts.^1-6 A cancer still can be masked on tomosynthesis (3D mammography) if it occurs in an area of dense tissue (where breast cancers more commonly occur), and tomosynthesis does not improve cancer detection appreciably in women with extremely dense breasts. To find cancer in a woman with dense breasts, additional screening beyond mammography should be considered.

Breast density and breast cancer risk

Dense breast tissue not only reduces mammography effectiveness, it also is a risk factor for the development of breast cancer: the denser the breast, the higher the risk.⁷ A meta-analysis across many studies concluded that magnitude of risk increases with each increase in density category, and women with extremely dense breasts (category D) have a 4-fold greater risk of developing breast cancer than do women with fatty breasts (category A), with upper limit of nearly 6-fold greater risk (FIGURE 2).⁸

Most women do not have fatty breasts, however. More women have breasts with scattered fibroglandular density.⁹ Women with heterogeneously dense breasts (category C) have about a 1.5-fold greater risk of developing breast cancer than those with scattered fibroglandular density (category B), while women with extremely dense breasts (category D) have about a 2-fold greater risk.

There are probably several reasons that dense tissue increases breast cancer risk. One is that cancers arise microscopically in the glandular tissue. The more glandular tissue, the more susceptible tissue where cancer can develop. Glandular cells divide with hormonal stimulation throughout a woman’s lifetime, and each time a cell divides, “mistakes” can be made. An accumulation of mistakes can result in cancer. The more glandular the tissue, the greater the breast cancer risk. Women who have had breast reduction experience a reduced risk for breast cancer: thus, even a reduced absolute amount of glandular tissue reduces the risk for breast cancer. The second is that the local environment around the glands may produce certain growth hormones that stimulate cells to divide, and this is observed with fibrous breast tissue more than fatty breast tissue. ●

Which of the following statements about breast density is TRUE?

_{Text copyright DenseBreast-info.org.}

Answer

D. The risks associated with dense breast tissue are 2-fold: Dense tissue can mask cancer on a mammogram, and having dense breasts also increases the risk of developing breast cancer. As breast density increases, the sensitivity of mammography decreases, and the risk of developing breast cancer increases.

A woman’s breast density is usually determined by a radiologist’s visual evaluation of the mammogram. Breast density also can be measured quantitatively by computer software or estimated on computed tomography scan or magnetic resonance imaging. Breast density cannot be determined by the way a breast looks or feels.

Breast density and mammographic sensitivity

Cancers can be hidden or “masked” by dense tissue. On a mammogram, cancer is white. Normal dense tissue also appears white. If a cancer develops in an area of normal dense tissue, it can be harder or sometimes impossible to see it on the mammogram, like trying to see a snowman in a blizzard. As breast density increases, the ability to see cancer on mammography decreases (FIGURE 1).

Standard 2D mammography has been shown to miss about 40% of cancers present in women with extremely dense breasts and 25% of cancers present in women with heterogeneously dense breasts.^1-6 A cancer still can be masked on tomosynthesis (3D mammography) if it occurs in an area of dense tissue (where breast cancers more commonly occur), and tomosynthesis does not improve cancer detection appreciably in women with extremely dense breasts. To find cancer in a woman with dense breasts, additional screening beyond mammography should be considered.

Breast density and breast cancer risk

Dense breast tissue not only reduces mammography effectiveness, it also is a risk factor for the development of breast cancer: the denser the breast, the higher the risk.⁷ A meta-analysis across many studies concluded that magnitude of risk increases with each increase in density category, and women with extremely dense breasts (category D) have a 4-fold greater risk of developing breast cancer than do women with fatty breasts (category A), with upper limit of nearly 6-fold greater risk (FIGURE 2).⁸

Most women do not have fatty breasts, however. More women have breasts with scattered fibroglandular density.⁹ Women with heterogeneously dense breasts (category C) have about a 1.5-fold greater risk of developing breast cancer than those with scattered fibroglandular density (category B), while women with extremely dense breasts (category D) have about a 2-fold greater risk.

There are probably several reasons that dense tissue increases breast cancer risk. One is that cancers arise microscopically in the glandular tissue. The more glandular tissue, the more susceptible tissue where cancer can develop. Glandular cells divide with hormonal stimulation throughout a woman’s lifetime, and each time a cell divides, “mistakes” can be made. An accumulation of mistakes can result in cancer. The more glandular the tissue, the greater the breast cancer risk. Women who have had breast reduction experience a reduced risk for breast cancer: thus, even a reduced absolute amount of glandular tissue reduces the risk for breast cancer. The second is that the local environment around the glands may produce certain growth hormones that stimulate cells to divide, and this is observed with fibrous breast tissue more than fatty breast tissue. ●

Which of the following statements about breast density is TRUE?

_{Text copyright DenseBreast-info.org.}

Answer

D. The risks associated with dense breast tissue are 2-fold: Dense tissue can mask cancer on a mammogram, and having dense breasts also increases the risk of developing breast cancer. As breast density increases, the sensitivity of mammography decreases, and the risk of developing breast cancer increases.

A woman’s breast density is usually determined by a radiologist’s visual evaluation of the mammogram. Breast density also can be measured quantitatively by computer software or estimated on computed tomography scan or magnetic resonance imaging. Breast density cannot be determined by the way a breast looks or feels.

Breast density and mammographic sensitivity

Cancers can be hidden or “masked” by dense tissue. On a mammogram, cancer is white. Normal dense tissue also appears white. If a cancer develops in an area of normal dense tissue, it can be harder or sometimes impossible to see it on the mammogram, like trying to see a snowman in a blizzard. As breast density increases, the ability to see cancer on mammography decreases (FIGURE 1).

Standard 2D mammography has been shown to miss about 40% of cancers present in women with extremely dense breasts and 25% of cancers present in women with heterogeneously dense breasts.^1-6 A cancer still can be masked on tomosynthesis (3D mammography) if it occurs in an area of dense tissue (where breast cancers more commonly occur), and tomosynthesis does not improve cancer detection appreciably in women with extremely dense breasts. To find cancer in a woman with dense breasts, additional screening beyond mammography should be considered.

Breast density and breast cancer risk

Dense breast tissue not only reduces mammography effectiveness, it also is a risk factor for the development of breast cancer: the denser the breast, the higher the risk.⁷ A meta-analysis across many studies concluded that magnitude of risk increases with each increase in density category, and women with extremely dense breasts (category D) have a 4-fold greater risk of developing breast cancer than do women with fatty breasts (category A), with upper limit of nearly 6-fold greater risk (FIGURE 2).⁸

Most women do not have fatty breasts, however. More women have breasts with scattered fibroglandular density.⁹ Women with heterogeneously dense breasts (category C) have about a 1.5-fold greater risk of developing breast cancer than those with scattered fibroglandular density (category B), while women with extremely dense breasts (category D) have about a 2-fold greater risk.

There are probably several reasons that dense tissue increases breast cancer risk. One is that cancers arise microscopically in the glandular tissue. The more glandular tissue, the more susceptible tissue where cancer can develop. Glandular cells divide with hormonal stimulation throughout a woman’s lifetime, and each time a cell divides, “mistakes” can be made. An accumulation of mistakes can result in cancer. The more glandular the tissue, the greater the breast cancer risk. Women who have had breast reduction experience a reduced risk for breast cancer: thus, even a reduced absolute amount of glandular tissue reduces the risk for breast cancer. The second is that the local environment around the glands may produce certain growth hormones that stimulate cells to divide, and this is observed with fibrous breast tissue more than fatty breast tissue. ●

Breasts that are heterogeneously dense or extremely dense on mammography are considered “dense breasts.” Breast density matters for 2 reasons: Dense tissue can mask cancer on a mammogram, and having dense breasts increases the risk of developing breast cancer.

Breast density measurement

A woman’s breast density is usually determined during her breast cancer screening with mammography by her radiologist through visual evaluation of the images taken. Breast density also can be measured from individual mammograms by computer software, and it can be estimated on computed tomography (CT) scan and magnetic resonance imaging (MRI). In the United States, information about breast density is usually included in a report sent from the radiologist to the referring clinician after a mammogram is taken, and may also be included in the patient letter following up screening mammography. In Europe, national reporting guidelines for physicians vary.

The density of a woman’s breast tissue is described using one of four BI-RADS® breast composition categories¹ as shown in the FIGURE.

A. ALMOST ENTIRELY FATTY – On a mammogram, most of the tissue appears dark gray or black, while small amounts of dense (or fibroglandular) tissue display as light gray or white. About 13% of women aged 40 to 74 have breasts considered to be “fatty.”²

B. SCATTERED FIBROGLANDULAR DENSITY – There are scattered areas of dense (fibroglandular) tissue mixed with fat. Even in breasts with scattered areas of breast tissue, cancers can sometimes be missed when they look like areas of normal tissue or are within an area of denser tissue. About 43% of women aged 40 to 74 have breasts with scattered fibroglandular tissue.²

C. HETEROGENEOUSLY DENSE – There are large portions of the breast where dense (fibroglandular) tissue could hide small masses. About 36% of all women aged 40 to 74 have heterogeneously dense breasts.²

D. EXTREMELY DENSE – Most of the breast appears to consist of dense (fibroglandular) tissue, creating a “white out” situation and making it extremely difficult to see through and lowering the sensitivity of mammography. About 7% of all women aged 40 to 74 have extremely dense breasts.²

Factors that may impact breast density

Age. Breasts tend to become less dense as women get older, especially after menopause (as the glandular tissue atrophies and the breasts may appear more fatty-replaced).

Postmenopausal hormone therapy. An increase in mammographic density is more common among women taking continuous combined hormonal therapy than for those using oral low-dose estrogen or transdermal estrogen therapy.

Lactation. Breast density increases with lactation.

Weight changes. Weight gain can increase the amount of fat relative to dense tissue, resulting in slightly lower density as a proportion of breast tissue overall. Similarly, weight loss can decrease the amount of fat in the breasts, making breast density appear greater overall. Importantly, there is no change in the amount of glandular tissue; only the relative proportions change.

Tamoxifen or aromatase inhibitors. These medications can slightly reduce breast density. 

Because breast density may change with age and other factors, it should be assessed every year.

Breasts that are heterogeneously dense or extremely dense on mammography are considered “dense breasts.” Breast density matters for 2 reasons: Dense tissue can mask cancer on a mammogram, and having dense breasts increases the risk of developing breast cancer.

Breast density measurement

A woman’s breast density is usually determined during her breast cancer screening with mammography by her radiologist through visual evaluation of the images taken. Breast density also can be measured from individual mammograms by computer software, and it can be estimated on computed tomography (CT) scan and magnetic resonance imaging (MRI). In the United States, information about breast density is usually included in a report sent from the radiologist to the referring clinician after a mammogram is taken, and may also be included in the patient letter following up screening mammography. In Europe, national reporting guidelines for physicians vary.

The density of a woman’s breast tissue is described using one of four BI-RADS® breast composition categories¹ as shown in the FIGURE.

A. ALMOST ENTIRELY FATTY – On a mammogram, most of the tissue appears dark gray or black, while small amounts of dense (or fibroglandular) tissue display as light gray or white. About 13% of women aged 40 to 74 have breasts considered to be “fatty.”²

B. SCATTERED FIBROGLANDULAR DENSITY – There are scattered areas of dense (fibroglandular) tissue mixed with fat. Even in breasts with scattered areas of breast tissue, cancers can sometimes be missed when they look like areas of normal tissue or are within an area of denser tissue. About 43% of women aged 40 to 74 have breasts with scattered fibroglandular tissue.²

C. HETEROGENEOUSLY DENSE – There are large portions of the breast where dense (fibroglandular) tissue could hide small masses. About 36% of all women aged 40 to 74 have heterogeneously dense breasts.²

D. EXTREMELY DENSE – Most of the breast appears to consist of dense (fibroglandular) tissue, creating a “white out” situation and making it extremely difficult to see through and lowering the sensitivity of mammography. About 7% of all women aged 40 to 74 have extremely dense breasts.²

Factors that may impact breast density

Age. Breasts tend to become less dense as women get older, especially after menopause (as the glandular tissue atrophies and the breasts may appear more fatty-replaced).

Postmenopausal hormone therapy. An increase in mammographic density is more common among women taking continuous combined hormonal therapy than for those using oral low-dose estrogen or transdermal estrogen therapy.

Lactation. Breast density increases with lactation.

Weight changes. Weight gain can increase the amount of fat relative to dense tissue, resulting in slightly lower density as a proportion of breast tissue overall. Similarly, weight loss can decrease the amount of fat in the breasts, making breast density appear greater overall. Importantly, there is no change in the amount of glandular tissue; only the relative proportions change.

Tamoxifen or aromatase inhibitors. These medications can slightly reduce breast density. 

Because breast density may change with age and other factors, it should be assessed every year.

Breasts that are heterogeneously dense or extremely dense on mammography are considered “dense breasts.” Breast density matters for 2 reasons: Dense tissue can mask cancer on a mammogram, and having dense breasts increases the risk of developing breast cancer.

Breast density measurement

A woman’s breast density is usually determined during her breast cancer screening with mammography by her radiologist through visual evaluation of the images taken. Breast density also can be measured from individual mammograms by computer software, and it can be estimated on computed tomography (CT) scan and magnetic resonance imaging (MRI). In the United States, information about breast density is usually included in a report sent from the radiologist to the referring clinician after a mammogram is taken, and may also be included in the patient letter following up screening mammography. In Europe, national reporting guidelines for physicians vary.

The density of a woman’s breast tissue is described using one of four BI-RADS® breast composition categories¹ as shown in the FIGURE.

A. ALMOST ENTIRELY FATTY – On a mammogram, most of the tissue appears dark gray or black, while small amounts of dense (or fibroglandular) tissue display as light gray or white. About 13% of women aged 40 to 74 have breasts considered to be “fatty.”²

B. SCATTERED FIBROGLANDULAR DENSITY – There are scattered areas of dense (fibroglandular) tissue mixed with fat. Even in breasts with scattered areas of breast tissue, cancers can sometimes be missed when they look like areas of normal tissue or are within an area of denser tissue. About 43% of women aged 40 to 74 have breasts with scattered fibroglandular tissue.²

C. HETEROGENEOUSLY DENSE – There are large portions of the breast where dense (fibroglandular) tissue could hide small masses. About 36% of all women aged 40 to 74 have heterogeneously dense breasts.²

D. EXTREMELY DENSE – Most of the breast appears to consist of dense (fibroglandular) tissue, creating a “white out” situation and making it extremely difficult to see through and lowering the sensitivity of mammography. About 7% of all women aged 40 to 74 have extremely dense breasts.²

Factors that may impact breast density

Age. Breasts tend to become less dense as women get older, especially after menopause (as the glandular tissue atrophies and the breasts may appear more fatty-replaced).

Postmenopausal hormone therapy. An increase in mammographic density is more common among women taking continuous combined hormonal therapy than for those using oral low-dose estrogen or transdermal estrogen therapy.

Lactation. Breast density increases with lactation.

Weight changes. Weight gain can increase the amount of fat relative to dense tissue, resulting in slightly lower density as a proportion of breast tissue overall. Similarly, weight loss can decrease the amount of fat in the breasts, making breast density appear greater overall. Importantly, there is no change in the amount of glandular tissue; only the relative proportions change.

Tamoxifen or aromatase inhibitors. These medications can slightly reduce breast density. 

Because breast density may change with age and other factors, it should be assessed every year.