Mammogram Screening Under Scrutiny—Part II

A good friend of mine wrote to me that approximately twenty years ago his wife had what was diagnosed as an aggressive type of breast cancer, discovered on routine mammogram screening. Both he and his wife feel that early detection was lifesaving and that the current diagnostic protocols are not aggressive enough. He wrote, “It’s one thing to speak globally about over diagnosis leading to over treatment, but there’s little consolation in being a statistic, the exception that proves somebody else’s rule.”

Many of us have a friend or family member with breast cancer, and some of us have lost loved ones to this disease. The subject of breast cancer can elicit powerful emotions in women. Whether the chance of benefiting from mammogram screening is worth the risks inherent in getting them regularly is an individual woman’s decision.

In my medical practice, I give the latest relevant data to the women who enquire about mammogram screening and then they make their own decisions. Recently, two very intelligent, well-informed patients of mine made two very different decisions on how to approach the issue.

Marianne is a 62 year-old nurse practitioner. She had one mammogram when she was forty years old and has no intention of getting any more—unless she finds a lump during one of her monthly self-breast exams or during her yearly clinical breast exam in my office. Her rationale for taking this approach is her awareness of the high false positive rates on routine screening, her lack of risk factors, and lack of family history of breast cancer.

A few weeks ago, Marianne said to me, “The risk of lethal lung cancer in women is greater than the risk of lethal breast cancer, and yet no screening for lung cancer is recommended. I don’t see women walking around in fear that they’ll get lung cancer. For some reason it’s not as terror-inducing a specter as is breast cancer. It doesn’t make sense to me.” Marianne said that she was willing to take the small risk that she would end up with an advanced breast cancer. She felt reassured that the treatment options for advanced breast cancer have been improving over time.

Three years ago at her annual check up, Marianne brought me a copy of a 2012 study published in the prestigious New England Journal of Medicine, letting me know that her decision was well-supported in mainstream medicine. http://www.nejm.org/doi/full/10.1056/NEJMoa1206809

At the end of the day, after finishing seeing patients, I read the article that Marianne brought to me. The study reported that over the last 30 years, mammograms have over-diagnosed 1.3 million women in the United States, accounting for nearly one-third of all newly diagnosed breast cancers. Millions more women have experienced the anxiety and emotional turmoil of a second battery of tests to investigate what turned out to be a false alarm. Most of the 1.3 million women who were over diagnosed received some kind of treatment—surgical procedures ranging from lumpectomies to double mastectomies, often with radiation and chemotherapy or hormone-blocking therapy too—for cancers never destined to bother them. Needless to say, these treatments pose their own dangers.

Ellen, on the other hand, age 50, feels that the U.S. Preventive Guidelines are too lenient. She has an aunt who got breast cancer in her 80s and she watched a close friend of hers die of breast cancer a few years ago. The experience left her traumatized.

Ellen knows that early detection from mammogram screening only helps a small percentage of women avoid dying of breast cancer each year, but, as she said, “those lives count, especially if you find yourself in that small percentage.”

Ellen has been getting yearly mammograms since she was 40 years old, based on the guidelines of the American Cancer Society. In the last 10 years, she has had two biopsies that were negative. She said that she would continue getting yearly mammograms because she saw on the ACS website that she has some of the risk factors for getting breast cancer: she drinks alcohol, eats processed foods, gets little exercise, and is overweight. She fully understands that she puts herself at risk of unnecessary interventions and treatment. She feels that the risks are justified.

I respect both of the women’s choices because they are making their decisions with full knowledge of the risks and benefits of their choices.

With such a highly charged subject, decisions need to be individualized. I cannot make this difficult decision for my patients, although many of them ask, “Can’t you just tell me what I should do?”

Some of my patients have figured out how to get around this roadblock by asking me what I personally do in relation to breast cancer. I tell them that I put most of my focus on breast cancer prevention and less on breast cancer detection.

The National Cancer Institute provides a free risk calculator on their website. http://www.cancer.gov/bcrisktool/

Who Has an Increased Risk of Getting Breast Cancer? 

The American Cancer Society has a list of risk factors for breast cancer on their website.

http://www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-risk-factors

In addition to the risks from environmental toxins, as well as lifestyle factors such as smoking, alcohol consumption, and lack of exercise, some of the other risk factors include the following:

Family history of breast cancer. A woman’s risk for breast cancer is higher if she has a mother, sister, or daughter (first-degree relative) or multiple family members on either her mother’s or father’s side of the family who have had breast cancer.

Having dense breasts. Breasts are made up of fatty tissue, fibrous tissue, and glandular tissue. A woman is said to have dense breasts when she has more glandular and fibrous tissue and less fatty tissue, as seen on mammograms. Women diagnosed with dense breasts on mammogram screening have a risk of breast cancer that is 1.2 to 2 times that of women with average breast density. Unfortunately, dense breast tissue can also make mammograms less accurate with a higher rate of both false positives and false negatives.

A number of factors can affect breast density, such as age (breasts tend to be more dense before menopause) and overstimulation of breast tissue from estrogen dominance due to genetics, obesity, and over-prescribing of hormones by healthcare providers.

Breast density laws have now been passed in California, Connecticut, New York, Virginia, and Texas, making it mandatory for radiologists to inform their patients who have dense breast tissue that mammograms are basically useless for them. A law is now being considered at a federal level as well.

Some radiologists already provide density information to their patients, and encourage them to utilize other options like thermography, ultrasound, and/or MRI.

Genetic mutations. Inherited mutations—or alterations—of certain genes, such as BRCA1 and BRCA2, can significantly increase women’s risk of breast cancer.

BRCA1 and BRCA2 are human genes that produce tumor suppressor proteins. These proteins help repair damaged DNA and, therefore, play an important role in ensuring the stability of the cell’s genetic material. When either of these genes is mutated, or altered, DNA damage might not be repaired properly. As a result, cells are more likely to develop additional genetic mutations that can lead to cancer.

When my sister’s daughter was thirty-three years old, she got genetic testing for the BRCA gene because her paternal aunt died at thirty-five from both ovarian and breast cancer.

The results of the genetic testing showed that my niece carries the BRCA 1 gene mutation, most likely inherited from her father, of Ashkenazi lineage. With that news in hand, my niece went to the Sloan-Kettering Cancer Center in New York for counseling. Her oncology team advised her to have her ovaries surgically removed and to get yearly mammograms the rest of her life for cancer surveillance.

Her oncology advisors agreed to postpone the oophorectomy surgery for a year to give my niece a chance to have a baby. Within the year, when she was thirty-five, she gave birth to a healthy baby boy.

I discussed with my niece the risks of getting a yearly screening test that involved radiation. Given that the BRCA mutations impair cells’ ability to repair DNA damage, women who carry these genes are more susceptible to the cancer-inducing effects of the x-rays used in mammograms. Other options to consider for yearly screening are MRI scans and breast ultrasounds—neither of which uses radiation.

The radiation from each mammogram is .4 mSv and is the equivalent of the radiation from four chest x-rays. (Each chest x-ray is .1 mSv.) If a woman followed the standard guidelines for getting mammograms every other year from age 50-74, she would have received the equivalent of 52 chest x-rays over her lifetime. If a woman followed the original guidelines from the American Cancer Society, she would receive the equivalent of 160 chest x-rays. And for women with the BRCA gene mutation, the exposure to radiation from yearly mammograms starting at age 30 and ending at age 80 would be the equivalent of getting 200 chest x-rays.

Up to 50 percent of women have dense breast tissue, which makes mammograms very difficult to decipher. Dense breast tissue and cancer both appear white on an x-ray, making it nearly impossible for a radiologist to detect cancer in these women. One radiologist described the challenge as “trying to find a snowflake in a blizzard.”

The chance of a false positive result is higher among women under the age of 50 due to the density of the breasts. Getting false positive results can cause needless exposure to the risks of treatments that include surgical deformities, radiation toxicity, and late effects of therapeutic radiation such as new cancers, scarring, and cardiac toxicity.

Of all breast cancers detected by screening mammograms, it is estimated that up to 54% are the result of over diagnosis. http://www.cancer.gov/types/breast/hp/breast-screening-pdq#cit/section_1.6

Mammograms have both a high false positive rate and a high false negative rate. False negative rate refers to the percentage of people whose mammogram results are negative when in reality there is indeed a tumor present, usually found on self-breast exam. Mammography misses about 16% of all breast cancers. Depending on certain factors, such as breast density in younger women, mammography may miss up to 30% of breast cancers.

http://www.cancer.gov/types/breast/hp/breast-screening-pdq#cit/section_1.6

When my niece learned of the potential harm from mammogram screening, she discussed with her oncologist the possibility of switching to MRI scans for the yearly surveillance.

The Pros and Cons of Using MRI Scans for Breast Cancer Screening 

The main advantage of using Magnetic Resonance Imaging (MRI) for breast cancer screening is the absence of radiation. MRI scans use strong magnets instead of radiation to make very detailed, cross-sectional pictures of the body. An MRI scan takes pictures from many angles, as if someone were looking at a slice of your body from the front, the side, or from above your head.

The most useful MRI exams for breast imaging use a contrast material that’s injected into a vein in the arm before or during the exam. This helps to clearly show breast tissue detail. The contrast material used for an MRI exam is gadolinium, a heavy metal that enhances the ability to detect abnormalities. The MRI scans with the contrast agent are highly sensitive in detecting abnormal breast tissue. 

MRI scans are especially useful for women with a higher risk of breast cancer and for evaluating dense breasts.

One major downside of missing so few cancers is the high rate of false positive results—meaning that the scan suggests that there is cancer present when, in fact, there is no cancer in the breast.

Although I had initially encouraged my niece to switch to MRI scans to avoid the radiation from mammograms, I soon realized how potentially dangerous the gadolinium contrast agent can be when used repeatedly, year after year. The heavy metal ions are excreted by the kidneys. In a small percentage of people, exposure to intravenous gadolinium has resulted in severe and irreversible kidney damage.

Just as troubling, researchers in Japan have recently confirmed an association between gadolinium and abnormalities in the brain, according to a new study published in the journal Radiology. The gadolinium accumulates in specific areas of the brain where it can increase the risk of multiple sclerosis and other neurological diseases.

http://www.biosciencetechnology.com/news/2013/12/breaking-news-mri-agent-linked-brain-abnormalities#.UsMrbfY77hW

My niece will return to the oncologist at Sloan-Kettering once again, this time armed with new data from various studies in support of her request to switch from MRI scans to breast ultrasounds.

The Pros and Cons of Using Breast Ultrasound for Cancer Screening 

The benefits of switching to breast ultrasound for screening young women with dense breasts are the absence of radiation found in mammograms and the absence of gadolinium, the potentially harmful contrast agent used with MRI scans. 

In December 2015, the Journal of the National Cancer Institute published an article with the title “Breast Cancer Detection Rate Using Ultrasound Is Shown To Be Comparable To Mammography.”

http://jnci.oxfordjournals.org/content/108/4/djv408.full 

Just in case one study was not enough to convince the oncologist to agree to switching my niece to yearly breast ultrasounds, I supplied her with a second article from the Journal of Basic Medical Science, May 2009, about a study comparing the sensitivity of ultrasounds to that of mammograms. The researchers concluded that the sensitivity of ultrasound screening was greater than mammography for detection of breast cancer in women with dense breasts and in younger women, premenopausal women.

http://www.ncbi.nlm.nih.gov/pubmed/19485945

As with the MRI scans, the breast ultrasounds also have a high false positive rate and often result in additional testing for many women, including biopsy, with most of the biopsies eventually found to be negative for cancer. Journal of Women’s Health, Sept. 2014

Other Methods of Breast Cancer Detection 

Breast thermography is a promising screening tool that has been approved by the FDA to be used in addition to mammogram. Some women use this screening modality alone, without the recommended mammogram. I do not have the data to report on the rate of false positives and false negatives.

Thermography involves standing with the breasts exposed in front of a sensitive device that detects the various degrees of heat throughout the breasts. No radiation is involved and the breasts are not touched.

Cancerous and pre-cancerous tissues have a higher metabolic rate resulting in growth of new blood vessels supplying nutrients to the fast growing cancer cells. As a consequence, the temperature of the area surrounding the pre-cancerous and cancerous breast tissue is higher when compared to the normal breast tissue temperature.

So, What Should Women Do? 

Continue self-breast exams once a month. If you menstruate, check your breasts in the early part of the cycle, shortly after the bleeding is finished, when there is the least hormonal stimulation. As reported in the Journal of Women’s Health, August 2011, statistics from a national database reveal that most breast cancers (56%) in the United States are discovered by breast exams performed in a clinic, or by self-breast exams.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153870/

An article in Mother Jones Magazine, written by science writer Christie Aschwanden, addresses the confusing subject of breast cancer screening in a clear and highly readable manner.

http://www.motherjones.com/politics/2015/10/faulty-research-behind-mammograms-breast-cancer

In the article, the writer quotes breast surgeon Susan Love. “If you feel something when you’re in the shower or putting on a shirt or making love, get it checked out,” says breast surgeon Susan Love, but it’s okay to stop thinking about your breasts as enemies. “If you look at what the benefits and harms are, and you decide to have a mammogram, that’s fine,” says Fran Visco, president of the National Breast Cancer Coalition. “And if you make a decision not to get one, that’s fine too.”

Avoiding an annual mammogram is hardly a “reckless” or “irresponsible act,” even if it means going against what your doctor has recommended. Many practitioners are too busy—or too indoctrinated— to consider the mounting research that shows that more women are being harmed by regular mammograms than are saved by them.

With all the “breast cancer awareness” events and “pink ribbons,” one might conclude that most women are well informed about breast cancer and that the route to breast cancer prevention is early detection.

Actually, however, women’s perceptions of the benefits of mammography do not match reality. And many doctors are just as confused as the average person on the street because of the media ignoring research that dramatically contradicts the “standard of care.”

In order to effectively decrease your chances of getting breast cancer, the focus needs to be on prevention. Even if you are at high risk of getting breast cancer, there is much you can do to lower your risk—in spite of your genes. The mutated genes need triggers to make them become harmful. If you avoid the triggers, you lower your risk.

To learn more about triggers for breast cancer and what you can do for prevention, you can read the three-part blog series I wrote about breast cancer prevention and treatment.

http://www.musingsmemoirandmedicine.com/2016/03/cancer-treatment-a-different-approach/

Here’s to your good health!

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While taking into account the latest research about breast cancer detection, may you also honor your own inner wisdom when choosing which path is right for you.