Breast health

Mammograms — what’s best for you?

by Dixie Mills, MD, FACS

The value of the annual mammogram is surprisingly ambiguous, and it’s important for every woman to understand the benefits and limitations of mammography so that she can make the choice that’s right for her. Here are the sections in this article:

• What exactly is the purpose of a mammogram?
  
• The controversial mammogram — objections to mammography
  
• Mammograms and breast cancer survival rates
  
• Does the size of the lump matter?
  
• What does “early detection” really mean?
  
• The “picture problem” with reading mammograms
  
• Dense breasts and dense mammograms?
  
• Alternatives to mammography
  
• The bottom line on breast health

Should you get an annual mammogram? Most women are told by their doctors that turning 40 means a yearly screening for the rest of their lives — a notion that reassures some but fills others with dread. If you don’t get a yearly mammogram are you more likely to die from breast cancer? The truth is more ambiguous than you may think.

We’ve been told that mammograms save lives, then we hear of a woman who had a clean mammogram three months prior to finding a lump in her breast and was dead in a year. What does this mean? The fact is, annual mammograms will not prevent you from getting cancer — they will detect some pre-existing lumps, but the technology (and the experience) is far from perfect.

Early detection through mammography is still the most important tool we have in beating breast cancer, especially if you have a family history or are over 65 — but it won’t protect you from cancer. At our practice, mammography is a supporting player in good breast health, not the lead role. We put as much (or more) emphasis on optimal nutrition, exercise, and a healthy lifestyle.

So, what about that annual mammogram?

The answer really depends on you. I’d like to give you the latest information so you can work with your practitioner and make an educated decision for yourself.

What is a mammogram?

Mammograms are black-and-white X-rays of a flattened breast. Annual mammograms allow a radiologist to detect something new or a change in your breast tissue. They don’t prevent or treat breast cancer. Getting your yearly mammogram is not like going to have your teeth cleaned and checked by the dentist, even though it may feel like a similar ritual.

After age 40 or 50, depending on your medical practice, mammograms become an additional feature of your annual well-woman exam that includes a physical exam of the breast and surrounding tissue. If you feel a lump it should be brought to the attention of your primary care provider (PCP) even if your mammogram was clean.

Over the past 30 years, mammograms have been shown to decrease breast cancer deaths in women over 50 years of age. The benefit for the women in their 40’s was never clearly demonstrated, begging the question of when is the best time to start — age 40 or 50? In some studies there was no difference, in others there was a smaller (10-20%) advantage. There’s no consensus among organizations in the field either: some recommend starting mammograms at 40, while others advocate 50. Most recommend stopping mammograms at age 70, but this is another controversial topic.

The general wisdom has been that the smaller the lump, the less time the cancer has had to grow, making it easier to eradicate. But as more information becomes available, that’s not so clear.

The controversy over mammograms

An article published in the July, 2005 issue of the Journal of the National Cancer Institute found that regular mammogram screening did not actually decrease deaths from breast cancer.

Advance reports of an article to be published in Cancer in September, 2005 implied that early detection boosted survival, but the benefit was much more substantial for women over 65. Yet another article published in August in JNCI reported that women whose breast lumps were detected by mammography had a better prognosis. So what is a woman to believe or to do?

Despite the news that the death rate from breast cancer has fallen somewhat, the incidence of breast cancer is still rising, albeit slowly. By now, we all have known or have had a friend who has been diagnosed with the disease and more and more of us know someone who died from breast cancer at a young age.

We still don’t know what causes breast cancer or how to prevent it — it’s definitely not like lung cancer where there is a clear link to nicotine and stopping smoking does save lives. If there were a similar connection between mammograms and breast lumps, there would be no controversy. Of course we want something that will save lives!

Most women are willing to undergo whatever testing they can to beat the odds of this frightening disease. So why am I hearing from more and more patients: “Do I really need that mammogram?”

Objections to mammograms

Mammograms are uncomfortable (and for some women, outright painful) and come with their own risks - high levels of false positives (about 10% per mammogram, depending on the age of the woman, the center, and the radiologist), unnecessary invasive procedures, and increased anxiety and dread — that need to be factored into the equation.

When my patients relate some of the humiliating experiences they’ve had getting a mammogram, I don’t blame them for never wanting to go back — whatever the risk. Our breasts are very personal and many of us aren’t that comfortable touching them ourselves, let alone manhandling them for an x-ray machine and a bossy technician!

Can mammograms cause breast cancer?

No study has ever asked this question directly, but scientists have estimated the accumulated radiation from mammograms over 10 years could contribute to one extra death from breast cancer in 10,000 women. The numbers would most certainly be skewed the other way if getting mammograms caused significant deaths. It’s possible we may be over-treating some women and controversy abounds over ductal carcinoma in situ (DCIS), but that will be addressed in a future article.

So, radiation from regular screening, including additional films beyond the norm, seems to be limited and acceptable for women 40 years and older. Some carriers of a genetic mutation are more susceptible to radiation damage and should have different screening. The radiation retained in the body from a mammogram can also be reduced significantly through complementary techniques, such as acupuncture or detoxifying foods like seaweed.

Nowadays, mammograms lead to the diagnosis of more cancers, particularly in situ cancers, without an increase in mortality. But are they actually saving lives? Yes, but not as many as you may have thought.

Breast cancer survival rates and mammograms

For every woman I see who declines the test I see one who wants a mammogram every month. Both ends of the spectrum are probably a bit too extreme about the issue. But the million-dollar question is, all things being equal (age, family history, general health), which of these patients is more likely to die from breast cancer?

Recently, a number of studies assert conflicting opinions on the subject of mammograms and survival rates. Keep in mind that studies can vary widely in scope, objective, quality of mammography and study design.

An overview article published in 2003 in the New England Journal of Medicine reviewed the literature and provided tables and graphs for doctors to help answer their patients’ questions. It dramatically showed that the number of lives saved through annual mammograms is much smaller than most women believe: two out of 1,000 women in their 40’s, four out of 1,000 in their 50’s, and six out of 1,000 in their 60’s.

I think that most women had assumed that the benefit of annual screening was much stronger and that mammograms were far more effective. Unfortunately mammograms don’t provide the direct protection and safety of seat belts or motorcycle and bicycle helmets. However, if you multiply by the millions of baby boomer women, these small percentages still add up to thousands of lives saved.

In another interesting study reported this July in the JNCI, researchers looked retrospectively at almost 4,000 women in the US between the ages of 40 and 69. Much to the surprise of the authors, the study found that women who underwent screening died at the same rate as women who declined a mammogram. Their results suggested there may be some benefit for women who are at an increased risk for breast cancer because of a family history or a prior atypical breast biopsy. (Click here for more information on breast cancer risk; this will link you to a free, interactive assessment tool. As recommended, please be sure to discuss the results with your doctor.)

Does the size of the lump matter?

A separate factor to consider is the size of the cancer — and there are plenty of studies that support the value of mammograms for early detection of small breast lumps.

A study conducted by doctors at Memorial Sloan–Kettering in New York City looked at over 260,000 breast cancer tumors from US Cancer Registry data. They found that improved survival rates over the last 30 years were the result of tumors being found at a smaller size rather than newer, advanced treatments. This was most dramatically true for women 65 years and older. The benefit was far less significant in women under 50.

The researchers did not have information on how many of these tumors were found on mammograms, but intuitively attributed the benefit to mammograms because mammograms can (but don’t always) find tumors smaller than those found during a breast self-exam or by a doctor.

So at this point, no one is ready yet to throw out mammography — except perhaps some insurance companies who see its rising cost — because early detection does appear to make a difference, however small. Just think if you were one of the two in 1,000 whose life was saved by a mammogram at 40.

But small tumors are often equated with early stage breast cancer. That’s not quite accurate, either. Let’s take a closer look.

Just what is early-stage breast cancer?

The benefits of early detection of a breast lump make intuitive sense — get it early and the disease has less chance to spread. But perhaps this is too simplistic. Breast cancer is not one disease, but the umbrella term for a host of cancers — and tumor size can reflect a range of progression depending on the cancer.

Let’s take the symptoms of breast cancer out of the box for a moment. In the first place — what is early? The size of an invasive tumor found on a mammogram is at least 5 mm but usually greater than that to be clearly seen. While this is tiny (to be felt by the hands a tumor is usually at least 10 mm, or 1 cm — about a half an inch — and more often larger), estimates of cell growth indicate that it takes many years to get to that size, annual mammogram or not.

Many researchers are now trying to identify markers either in the blood, urine, or ductal fluid that could signal the presence of tumors at a really early stage. We now realize that not all 1 cm tumors are created equal either. Genetic micro array analysis of tumors is beginning to identify which tumors are the aggressive “bad” actors and which are the slow indolent type.

Likewise, not all 2–inch or 5–cm tumors are the same. We had assumed that cancer cells and tumors grew in an orderly fashion from a pea to a grape to a walnut. But not all tumors fit this stereotype: some stay pea-like; some grow like weeds in springtime and lay dormant in the winter; others feed off hormones or starve for unknown reasons.

So while we can say that early detection is important and finding tumors at a smaller size is beneficial it is not the whole story. And mammograms can get it wrong because the technology is far from perfect.

Mammography and the “picture problem”

A number of difficulties exist in getting a quality image of the breast, otherwise known as what best-selling author Malcolm Gladwell calls the “picture problem.” In the 2–D world of mammography, two black-and-white pictures of each breast are taken. These contrasting views provide some dimension, but little more than what is up, down, medial, or lateral.

Up until the 1960’s basic x-ray equipment was used to look at the breast and chest cavity. Compression imaging was introduced in the early 1980’s, which simplified the process and provided a better view — opening the door to mass screenings. While the radiation doses have decreased significantly since the 1960’s, not much else has changed.

Frankly, I’m surprised we’ve progressed from color television to high-definition TV while women’s breasts are still being imaged with black-and-white x-rays. I comment to my patients on the quality of video games available to our children — all with better depth and detail than the average mammogram! Even my dentist has a computer next to each patient’s chair that shows a real-life image of each tooth. But decay in the mouth is now easier to spot than cancer in a woman’s breast.

Mammograms are clearest when imaging fatty breasts, which are more prevalent in older women — usually post-menopausal women not on HRT. Higher hormone levels cause breasts to be fibrous and hard to read on a mammogram — or “dense.” (Perhaps this is the reason mammograms are more beneficial for older women). How your breasts feel does not always correlate with how they look on mammograms; lumpy breasts can be dense or not to the x-ray machine.

A textbook cancer — or as some doctors would say, one that a medical student could see — would show up on a mammogram as an irregular or spiculated (jagged) white shape, often called a mass or a nodule. (Nodes are the little shapes seen up in the armpit on films.) The white shape shows up best on a background of gray or black, which is fat on a mammogram.

I make it a point to show all my patients their films, and I suggest you ask your breast specialist to show you yours. (Note that PCP’s do not actually see the films and instead rely on the radiologist’s report and therefore could not discuss your films with you.) In these conversations I’ve learned that most women are unfamiliar with reading film negatives and assume that what is white is background and what is black is an object — so they often point to a black area with concern. But the black area is actually good fat, and it’s the white areas that we must examine closely.

Dense breasts contain a lot of perfectly normal fibroglandular tissue that shows up as white areas on a mammogram. Part of the “picture problem” with mammograms of dense breasts is that the white areas created by those fibrous tissues can conceal a small cancer — especially one a medical student could not see.

Dense breasts and “dense mammograms”

Every woman should be told how dense her mammograms are. (I tell all my patients that they aren’t dense, just their mammograms!)

Dense breast tissue is partially genetic and you won’t know if you’ve inherited it until you get a mammogram — but it relates directly to the likelihood of detecting a cancer with mammography, especially if you are under 50. It may take a bit of sleuthing because radiology reports are not easy to interpret and are not universally the same.

To offset the frustration of a dense mammogram reading, I recommend that women have their mammograms taken consistently at the same accredited site. (It’s against the law to provide mammograms without being accredited, so it is rare that a center wouldn’t be.)

Women with family histories or other high risk factors should be screened at a breast center where they can be informed of their results the same day and have additional testing (if necessary) done at that same time or scheduled in a timely fashion. In an ideal world all women could have their testing done this way — what a lot of fear and loathing that would relieve! Unfortunately, the cost of this kind of practice can be prohibitive and there are not enough dedicated mammographers (radiologists who specialize in the breast) to make it feasible for everyone.

Keep in mind that not all mammograms are double-read and all are subject to human error. Sometimes the person reading them can be tired or less experienced. Doctors are not going into mammography now for fear of being sued over dubious results that come from the imperfect technology. For these reasons getting a second opinion is always a good idea.

Are dense breasts a risk factor for breast cancer? The physiology is totally unclear; most likely this is more a matter of difficulty in reading the dense mammogram. If your mammograms are dense, annual screening in your 40’s is certainly going to be less helpful. Depending on your risk factors or personality you may want to forgo annual mammograms (perhaps go every two to three years) until age 50 or pursue other means of screening.

Can you make mammograms less dense? Unfortunately there is no simple answer here. Aging helps some, but if you want an immediate solution you can try having your mammogram right after your period when your hormones are lower. This can be somewhat difficult to schedule. We also know that taking HRT usually keeps pictures dense.

What are the alternatives to mammography?

If your mammograms are dense or you do not believe in or want to have a mammogram, you may want to have ultrasound screening. For those women with a strong risk history, an MRI scan is another option. Not all centers will provide these services and they can be expensive, so not all insurance policies cover them.

Some institutions have digital mammography, where the pictures are stored on a computer (rather than film) and seen on a high-resolution monitor. The computer aids in analyzing the changes from year to year. Like all advanced technology, this equipment is upgraded yearly and is still very expensive. Digital mammography offers significant benefits over film for premenopausal women and women with dense breasts, according to a recent study published in NEJM. Both groups are equally prone to giving false positive results. The benefits aren’t totally clear, but do allow a radiologist to view your file from a remote location (good for second opinions!). Regardless, not all mammography centers have bought into it.

Thermography and breast cancer detection

Thermography, or heat detection, is an old method which newer technology is bringing back. At this point, very few large studies have looked at thermography. I think it is still too early to advocate it for everyone.

I’ve encouraged women interested in the test to find an experienced institution that will correlate their findings with other testing. I personally have seen false positive and false negative results with different practitioners using different types of cameras. However, if you know of a healthcare provider accredited in thermography, it might be something to try. We’ll keep you posted as more information becomes available.

I still think I may be able to become the curator of a mammogram museum before I die, because technology is advancing by leaps and bounds and breakthroughs that make our current machines obsolete are sure to occur!

What is the bottom line on mammograms?

I think it’s prudent to continue annual mammograms, particularly for women over 50 and definitely those over 65, but it should always be a choice, not an obligation. If annual mammograms go against your belief system, reason, or common sense — don’t worry. You will not be arrested or ticketed and your likelihood of dying from breast cancer is still very small if you decline the test.

What you should take into account is your own individual health picture: your risk factors, age, breast density, and your threshold for anxiety and risk. Some women may be comfortable getting a mammogram only a couple times in their 40’s and 50’s; others may need more regular reassurance.

Our approach to breast health

Whatever you decide in regard to your annual mammogram, the following guidelines will help you build a core foundation of breast health. Even women with a genetic predisposition toward breast cancer may offset some of their risk through good nutrition, daily exercise, and positive lifestyle choices. Here’s what we recommend:

• If you still smoke, stop.
• Eat 5-9 servings of fresh fruit and vegetables per day, preferably organic or locally-grown produce, free from pesticides and synthetic fertilizers. Avoiding simple sugars and carbohydrates can help prevent insulin resistance, which may be linked to a higher breast cancer risk.
• Take a medical-grade nutritional supplement. Your breast health relies on a rich supply of nutrients, including antioxidants and essential fatty acids to help boost the immune system and soothe inflammation.
• Eat healthy, organic animal and dairy fats. The link between saturated fat and breast cancer is a hot topic - whether the risk comes from saturated fat itself or the biotoxins that accumulate in the fat cells of our food is still unclear.
• Drink alcohol in moderation. More than 1–2 glasses of wine or spirits per day has been associated with greater breast cancer risk because it interferes with your liver’s ability to metabolize extra estrogens.
• Exercise for 30–60 minutes at least 4 times a week. Try to shed excess body weight.
• Try to practice monthly self-breast exams or have a partner do them for you. Click here for information, directions, and visual guides on self-breast exams.
• Get annual well-woman exams, starting at age 20. Discuss with your doctor the appropriateness of annual mammograms for you, particularly if you’re under 50 or have dense breast tissue.
• If you have a family history or prior atypical biopsy results, check with your doctor and follow up at an accredited breast center.

In a perfect world

Mammography is definitely not as good as anyone thought it could be or as beneficial as we’d like it to be but we are still better off than we would be without it. However we shouldn’t think this is as good as it gets.

My hope or dream is that in the near future there will be a simpler, better test like blood or urine for breast cancer. If a woman turns up positive, she could then go on to have a diagnostic mammogram, ultrasound or MRI. Or better yet, maybe someday the innovation of the year will be a cream that a woman rubs on her breast: if it turns a particular color then she opens a different tube and rubs on another cream that makes everything all right! One can dream, can’t one?

Related to this article:

References & further reading on mammograms

 

Original Publication Date: 08/30/2005
Last Modified: 03/11/2010
Principal Author: Dixie Mills, MD