Breast Density — What does it all mean?
About six months ago I was attending a conference where a breast specialist was giving a lecture. She started by asking, “Who in this room (which was full of doctors and other health care providers) thinks that by sending your patients for mammograms, you are helping them to prevent breast cancer?” About 75% of the attendees raised a hand. She looked around, and after a beat, said “That’s bullshit!”. You are not preventing breast cancer by sending patients for mammograms — -you are merely — and only SOME of the time — finding it a bit earlier…..”
I thought about that for a minute. Yes — -that is probably true….but also very disconcerting. I always liked to think that by regularly coming to the doctor, having all of the tests we recommend, and taking care of their health, patients can somehow control — or at least participate in controlling their health outcomes. Having annual mammograms seemed to be the “best we had” as far as breast cancer reduction…..Thank goodness that for the rest of the lecture she went on to discuss and describe exactly what WE as health care providers CAN do to help our patients prevent breast cancer, and since that lecture I have incorporated many of her recommendations into my office practice.
A mammogram, for those who are unfamiliar, is an X-Ray picture of the breasts. We use them to look for early signs of breast cancer. The breasts are placed, one at a time, on a clear plastic plate, and another plate compresses the breast from above. Several pictures are taken in various angles to image all of the tissue in each breast. The process is uncomfortable to say the least, and sort of like placing the breasts into a vise for a few seconds at a time. Mammograms are a lower dose of radiation than other X-Rays, and it is thought that the benefits of finding breast cancer outweigh the small amount of radiation exposure. It is by no means a perfect exam, but with newer technology, like 3D mammograms, the breast tissue can usually be seen more clearly, finding smaller areas that are suspicious for cancer.
Several years ago, legislation was passed stating that patients undergoing mammograms need to be informed about what type of density category their particular breast tissue falls into. (This is currently the law in 30 states in the US). The intent of that law was to give women the necessary information to decide on further action if they had dense breast tissue. However, in my experience, it has caused more confusion, as women now have information that (A) they have dense breast tissue, and (B) that somehow puts them at increased risk for breast cancer…..but who, if anyone, is explaining these details? Usually no one. Who is reviewing the different types of breast density, and discussing what women should do with this new information? Often, no one. And, as my astute lecturer asked at that conference, how can we help to prevent breast cancer, not just FIND it?
First, what is meant by “breast density”?
Dense breast tissue is breast tissue that is comprised of less fat and more connective tissue. As a woman ages, her breasts usually become more fatty and less dense. However, some women (2/3 of pre-menopausal, and 1/4 of post-menopausal women) have dense breast tissue. Dense breast tissue appears white on a mammogram, and cancers also appear white on a mammogram. Tumors can be hidden or masked by the areas of dense breast tissue, and the denser the tissue, the harder it may be to see a small cancer. There are four categories of breast density, from least dense (and therefore least concerning) to most dense (and therefore more worrisome, both because of an inability to see well, and because dense tissue itself is an independent risk factor for cancer). The categories are:
— 1 — -fatty breast tissue
— 2 — -breast tissue with scattered fibroglandular densities
— 3 — -heterogeneously dense breast tissue
— 4 — -extremely dense breast tissue
Women with the last two categories of breast density — heterogeneous and extremely dense breast tissue, have an increased risk of breast cancer over the first two categories. So — — great — what to do about this? It is not enough to just give patients this information. It is up to US as health care practitioners, to put these risks in perspective, and to help formulate a plan to actually try to decrease the risk of breast cancer in the future, especially in light of the increases in risk due to density type.
The consultation I do in my office regarding breast density and breast cancer risk is not one that I can do within the annual gyn exam, or over the phone. It is a 30-minute sit-down conversation to talk about risk factors, breast density, lifestyle and family factors. It begins with a checklist and ends with a plan. It is designed to equip women with information, and the idea that some of this is actually in their control, and that there are things they can do to lower their risk. There is a very informative website, that I use for part of my consultation with patients about breast density/breast cancer prevention.
I first ask many historical and lifestyle questions: These questions are about overall health, age at first menstrual period, info about pregnancy, breastfeeding, alcohol intake, exercise habits, history of breast biopsies, family history, medications, birth control used, menopause and mammogram results, including breast density reports. ALL of these things influence a woman’s risk of breast cancer, to varying degrees.
Then we go more into detail about family history. It is now known that 1 in 40 women of Ashkenazi Jewish (Eastern European) descent carries a breast cancer gene. Taking a very specific and detailed family history tells us which women should be tested for genetic links to breast cancer, and also which women have increased risk simply because there are other people in their family with a breast cancer diagnosis. Any woman who qualifies to test for genetic mutations should be tested for these mutations, as finding a genetic link to breast cancer (BRCA 1 and BRCA 2 are the most “well known” of these genes, but there are actually many others) greatly increases the risk of cancer, and also allows for other diagnostic testing and treatments to be considered.
There are several screening algorithms that can be used to assess breast cancer risk. One is called the Gail model, and another is called the Tyrer-Cuzick model. There are others. These are designed to work as a a tool to estimate a woman’s breast cancer risk over the next five years and over the course of her lifetime. They utilize many different parts of the woman’s history, including type of breast density. These are fed into the computerized algorithm, and result in a number — a number representing a percentage of risk for that individual woman. These numbers are important for many reasons. For example, if the “average” woman (with NO genetic or family risk factors) has a 13% chance of having breast cancer over the course of her lifetime, then numbers higher than this may represent an increased risk, and there may be things we can recommend (medications, other diagnostic tests like ultrasounds or breast MRIs, or even surgeries) in individual circumstances, for individual patients that can substantially lower their risk.
Finally, we discuss all of the patient’s modifiable and non-modifiable risk factors and formulate a plan.
1- Alcohol: Compared to women who do not drink alcohol, women who drink more than 3 five-ounce glasses of alcohol per week increase their risk of breast cancer by 15%. Think about that — — a completely modifiable risk factor. I am often amazed that women who are “afraid” to have a mammogram because of fear of radiation (a scientifically unfounded fear) will not acknowledge that their alcohol habit poses more of a risk for breast cancer than the mammogram. Decreasing alcohol consumption can have a substantial effect on the risk for future breast cancer, and this is one of the recommendations I make for women at risk.
2- Weight: Being overweight or obese especially after menopause increases a woman’s risk for breast cancer. One of the initial “checklist” questions has to do with how much weight increase has there been since going into menopause — and often there has been a ten pound, or more — weight increase. (Metabolism slows down during menopause) Excess body fat affects immune function, inflammation, and may also raise hormone levels that can stimulate the growth of cancer cells. While the links between body weight and cancer are not fully understood, The American Cancer Society believes excess body weight is responsible for about 8% of cancers in the US. Aiming for a “normal” BMI (depending on individual body type and history) below 25 is a reasonable goal, but a healthy diet based on vegetables, plant proteins and healthy fats is a good start. A good plan to follow:
3- Exercise: It is thought that physical activity regulates hormones including Estrogen and Insulin, which can both affect the growth of breast cancer. Regular exercise can also help keep women at a healthy weight, which helps maintain a healthier immune system. The American Cancer Society recommends 150 minutes of moderate intensity exercise per week, or 75 minutes of vigorous exercise per week, preferably spread throughout the week. Even if exercise has not been a part of a woman’s lifestyle, it is never too late to start, and starting slow and building up can ultimately have the same effect. I strongly advise that for women who want to do something to decrease their breast cancer risk as well as to reduce the risk of other medical conditions, exercise MUST be a part of their lifestyle.
4- Family: Women who qualify to do genetic testing should test, and a thorough discussion follows after this testing, whether the results are positive, negative, or (sometimes) inconclusive. For women who are found to have certain genetic mutations, a “spreadsheet” of sorts is formulated, listing all of the additional surveillance, diagnostic testing, and possible treatments that are now available to her. This spread sheet follows her for the rest of her life, with the intention of doing all that can be done to now lower her (substantially increased) risk of breast (and sometimes other) cancers. Women who have no genetic mutations are also counseled regarding what a negative test result means, and how that will affect her future risk for cancer. A website for info on genetics and cancer risk:
5- Algorithm results: Based on the resulting percentages from several risk algorithms, recommendations are made as to what surveillance, which possible medications (yes — there are medications available in the right circumstances to reduce the risk for future breast cancer) which diagnostic studies (according to the National Comprehensive Cancer Network, a woman who scores above 20% risk on the Tyrer-Cuzick algorithm should have NOT just a mammogram, but a breast MRI annually — and I have gotten insurance companies to approve these tests, based on these guidelines) can be offered to women as a way to reduce risk, or find cancer even earlier.
At the end of this consultation, a patient has SO much more information than just “your breasts are dense”. She can make informed, coordinated decisions on what lifestyle changes she can make, what testing is available to her, what her individual risk for breast cancer is and what she might want to do to modify that. There are many things that cannot be changed — -(we cannot change our family history or our genetics )—and there are many women who are diagnosed with breast cancer even when modifying ALL of their modifiable risks. Although breast density may not be something we can change, it is not just an additional piece of information to file away until next year’s mammogram. Understanding its importance, and knowing that there are things that we CAN do and that we CAN change, even a little — can be important and empowering information. It can help women take control and take responsibility for maximum risk reduction. And that is infinitely better than making decisions based on fear, hearsay, or non scientific internet chatter.