Mammography False Alarms Linked with Later Tumor Risk

mammography screening

Story at-a-glance

  • In the US, the risk of having a false-positive test over 10 mammograms is a concerning 58 percent to 77 percent!
  • When a woman is told she may have breast cancer, it causes considerable anxiety and psychological distress
  • It's important to remember that getting a mammogram, if you choose to, is not the same as prevention, which is much better served via healthy lifestyle choices


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

One of the reasons why you must carefully consider the decision to have a mammogram is due to their high rate of false positives. A false positive occurs when a mammogram suggests a woman has cancer when none actually exists.

In the US, the risk of having a false-positive test over 10 mammograms is a concerning 58 percent to 77 percent!1, 2 When a woman is told she may have breast cancer, it causes considerable anxiety and psychological distress. Meanwhile, you will be subjected to more testing, such as biopsy or surgery, which carry their own set of risks, unnecessarily.

Now, new research has found, however, that women who have received a false-positive diagnosis via mammography may be more likely to develop breast cancer years later, although no one is quite sure why.

Does Getting a False Positive on a Mammogram Mean You’re More Likely to Develop Breast Cancer Later On?

Out of 58,000 Danish women who had had a mammogram, more than 4,700 were found to have false positives (the false-positive test rate in Denmark is about 16 percent -- much lower than it is in the US). About 1.5 percent of those turned out to be false-negatives, meaning that the doctors missed the cancer the first time around.

However, even after taking these false-negatives into account, women with false-positive mammograms were still 27 percent more likely to be diagnosed with breast cancer years later. As for what this means for women, no one really knows, but the researchers suggested their results favor some “biological susceptibility” as an explanation.

They suggested further research to determine the true excess risk of false positives, and future studies should definitely look into all of their related risks… like the increases in stress levels, unnecessary biopsy, and perhaps additional mammograms, which all have the potential to impact breast cancer risk.

Emotional Stress Might Increase Cancer Risk

There’s much yet to be learned about cancer development and progression, but it is known that emotional stress plays a role… and receiving news that you might have cancer, even if it later turns out that you don’t, is high up there on the stress scale.

For instance, a study by Yale University researchers found that stress, even the “normal” everyday variety, can act as a pathway between cancerous mutations, potentially triggering the growth of tumors.3 So it’s not a stretch to suggest that some women’s emotional stress, caused by a false-positive mammogram, could trigger breast cancer later on.

The National Cancer Institute, meanwhile, has also said that research with animal models suggests that “your body’s neuroendocrine response (release of hormones into your blood in response to stimulation of your nervous system) can directly alter important processes in cells that help protect against the formation of cancer, such as DNA repair and the regulation of cell growth.”4

Still, other research has shown that norepinephrine, a hormone produced during periods of stress, may increase the growth rate of cancer.5

Norepinephrine can stimulate tumor cells to produce two compounds (matrix metalloproteinases called MMP-2 and MMP-9) that break down the tissue around the tumor cells and allow the cells to more easily move into your bloodstream.

Once there, they can travel to other organs and tissues and form additional tumors, a process called metastasis. Norepinephrine may also stimulate the tumor cells to release a chemical (vascular endothelial growth factor or VEGF) that can aid in the growth of the blood vessels that feed cancer cells. This can increase the growth and spread of the cancer.

The stress hormone epinephrine has also been found to cause changes in prostate and breast cancer cells in ways that may make them resistant to cell death.6 This means that emotional stress could both contribute to the development of cancer and reduce the effectiveness of treatments.

Unnecessary Surgery, Biopsy, and Mammograms Might Also Influence Your Cancer Risk

Along with stress, a false-positive mammogram might cause you to have unnecessary treatments that increase your cancer risk. Needle biopsies, for instance, are widely used as part of the traditional allopathic approach to diagnosing breast cancer.

During a biopsy, a piece of tissue from a tumor or organ is removed so that it can be examined under a microscope, often to determine if it is cancerous. However, the procedure may accidentally cause malignant cells to break away from a tumor, resulting in its spreading to other areas of your body.

According to a study from the John Wayne Cancer Institute, it appears that a needle biopsy may increase the spread of cancer by 50 percent compared to patients who receive excisional biopsies, also known as lumpectomies.7

There’s also the probable chance that women receiving false-positives will receive more frequent mammograms in the future, which exposes women to more ionizing radiation, a known carcinogen. Results published in the British Medical Journal (BMJ) show that women carrying a specific gene mutation called BRCA1/2 are particularly vulnerable to radiation-induced cancer.8

Women carrying this mutation who were exposed to diagnostic radiation before the age of 30 were twice as likely to develop breast cancer, compared to those who did not have the mutated gene.

They also found that the radiation-induced cancer was dose-responsive, meaning the greater the dose, the higher the risk of cancer developing.  Meanwhile, research has shown that trauma to the breast itself can cause cancer.9 According to the authors:

“Models of epithelial cell generation indicate that a causal link between physical trauma and cancer is plausible. A latent interval between cancer onset and presentation of under 5 years is also plausible. The most likely explanation of the findings is that physical trauma can cause breast cancer.”

And, as reported by Science News in 2011:10

“The slightest scratch can cause cancerous cells to crawl to the wound and form tumors in mice… The work may explain why certain kinds of cancers seem to cluster around burns, surgical scars and other injuries.

'This work says that if you have a predisposition to getting cancer, wounding might enhance the chance that it will develop,' says cell biologist Anthony Oro of Stanford University School of Medicine.”

This raises questions about the possibility of developing cancer in the remaining or surrounding chest tissue following a surgery such as a lumpectomy or even a double mastectomy. Believe it or not, women having double mastectomies unnecessarily happens more often than you might think, even in cases that don’t involve a false-positive.

70 Percent of Double Mastectomies Aren’t Necessary

According to a study published in JAMA Surgery,11 70 percent of women who have breast cancer in one breast and undergo a double mastectomy do so unnecessarily. The study found medical reason for only 10 percent of women diagnosed with breast cancer to consider this type of mastectomy, yet rates of the procedure are on the rise.

Compared to the 1990s, when only about 1 percent of women diagnosed with breast cancer opted to have a double mastectomy, in recent years that percentage has climbed to 20 percent.12 TIME magazine recently highlighted four reasons why women may choose to have this invasive procedure even though studies don’t show any benefit to survival (or reducing recurrence) by removing an unaffected breast:13

  1. Fear of doing nothing: Fear may overshadow reason, driving women to opt for drastic surgery. Research shows, however, that breast cancer patients are more likely to develop recurrent tumors in their liver, lungs, or brain than they are in their other breast.
  2. Early detection leading to too much information: Early screening may detect lesions that may never turn into cancer and don’t require treatment, but once you know a lesion is there, you may decide to treat it anyway.
  3. The pink ribbon brigade: Plastering pink ribbons on every conceivable product has much more to do with raising awareness of, and money for, the Komen Foundation than it does curing breast cancer. It also contributes to a “hyper awareness” surrounding prophylactic mastectomy, leading some women to choose it without understanding the risks and benefits.
  4. Not enough information about options: Many women may not receive accurate information about alternatives to prophylactic mastectomy from their doctors, which means they’re unable to make an informed decision.

The Facts About Mammography: No Impact on Breast Cancer Mortality

Many US women dutifully get their annual mammogram, believing it to be a proactive way to reduce their risk of dying from breast cancer. You may not have heard, however, about a study published in the British Medical Journal (BMJ) -- one of the largest and longest studies of mammography to date -- involving 90,000 women followed for 25 years. It found that mammograms have absolutely NO impact on breast cancer mortality.14 Over the course of the study, the death rate from breast cancer was virtually identical between those who received an annual mammogram and those who did not, while 22 percent of screen-detected invasive breast cancers were over-diagnosed, leading to unnecessary treatment. The experts noted:

"This means that 106 of the 44,925 healthy women in the screening group were diagnosed with and treated for breast cancer unnecessarily, which resulted in needless surgical interventions, radiotherapy, chemotherapy, or some combination of these therapies."

A Cochrane Collaboration review also found no evidence that mammography screening has an effect on overall mortality,15 which, taken together, seriously calls into question whether mammography screening really benefits women. On the contrary, in one survey, most women said they believed mammography reduced the risk of breast cancer deaths by at least half and prevented at least 80 deaths per 1,000 women screened.16 In reality, mammography may, at best, offer a relative risk reduction of 20 percent and prevent in absolute terms only one breast-cancer death per 10,000 women. The experts asked a long overdue question:

"How can women make an informed decision if they overestimate the benefit of mammography so grossly?"

The sad reality of course, is that they can't. Many women are still unaware that the science backing the health benefits of mammograms is sorely lacking. Instead of being told the truth, women are guilt-tripped into thinking that skipping their yearly mammogram is the height of irresponsibility. It can be hard to stand your ground against such tactics. After all, you expect health professionals to know what they're talking about, and to give you the best advice possible. When it comes to cancer prevention, however, many doctors are just as confused and manipulated as the average person on the street because of the relentless industry and media propaganda that downplays or ignores research that dramatically contradicts their profit-based agenda.

Lifestyle Tips to Lower Your Breast Cancer Risk

It's important to remember that getting a mammogram, if you choose to, is not the same as prevention. And cancer screening that does more harm than good can hardly qualify as "your best bet" against becoming a cancer statistic. I believe the vast majority of all cancers, including breast cancer, could be prevented by strictly applying basic, commonsense healthy lifestyle strategies, such as the ones below.

  • Avoid sugar, especially fructose, and processed foods. All forms of sugar are detrimental to your health in general and tend to promote cancer. Refined fructose, however, is clearly one of the most harmful and should be avoided as much as possible. This automatically means avoiding processed foods, as most are loaded with fructose.
  • Optimize your vitamin D levels. Vitamin D influences virtually every cell in your body and is one of nature's most potent cancer fighters. Vitamin D is actually able to enter cancer cells and trigger apoptosis (programmed cell death). If you have cancer, your vitamin D level should probably be between 70 and 100 ng/ml. Vitamin D works synergistically with every cancer treatment I'm aware of, with no adverse effects. Ideally, your levels should reach this point by exposure to the sun or a safe tanning bed, with oral vitamin D used as a last resort.
  • Limit your protein. Newer research has emphasized the importance of the mTOR pathways. When these are active, cancer growth is accelerated. One way to quiet this pathway is by limiting your protein to one gram of protein per kilogram of lean body mass, or roughly a bit less than half a gram of protein per every pound of lean body weight. For most people, this ranges between 40 and 70 grams of protein a day, which is typically about 2/3 to half of what they are currently eating.
  • Avoid unfermented soy products. Unfermented soy is high in plant estrogens, or phytoestrogens, also known as isoflavones. In some studies, soy appears to work in concert with human estrogen to increase breast cell proliferation, which increases the chances for mutations and drives the phenotype associated with cancer.
  • Improve your insulin and leptin receptor sensitivity. The best way to do this is by avoiding sugar and grains and restricting carbs to mostly fiber vegetables. You can also use intermittent fasting, especially if you are overweight. Also make sure you are exercising, especially with Peak Fitness.
  • Exercise regularly. One of the primary reasons exercise works to lower your cancer risk is because it drives your insulin levels down, and controlling your insulin levels is one of the most powerful ways to reduce your cancer risks. It's also been suggested that apoptosis (programmed cell death) is triggered by exercise, causing cancer cells to die in the way nature intended. Studies have also found that the number of tumors decrease along with body fat, which may be an additional factor. This is because exercise helps lower your estrogen levels, which explains why exercise appears to be particularly potent against breast cancer.
  • Maintain a healthy body weight. This will come naturally when you begin eating right and exercising. It's important to lose excess body fat because fat produces estrogen, creating a vicious self-perpetuating cycle.
  • Drink a pint to a quart of organic green vegetable juice daily. This is a simple way to get more cancer-fighting nutrients into your diet. Please review my juicing instructions for more detailed information.
  • Get plenty of high-quality, animal-based omega-3 fats, such as krill oil. Omega-3 deficiency is a common underlying factor for cancer.
  • Take curcumin. This is the main active ingredient in turmeric and in high concentrations can be very useful adjunct in the treatment of cancer. It actually has the most evidence-based literature supporting its use against cancer of any nutrient, including vitamin D.17 For example, it has demonstrated major therapeutic potential in preventing breast cancer metastasis.18 It's important to know that curcumin is generally not absorbed that well, so I've provided several absorption tips here. Newer preparations have also started to emerge, offering better absorption. For best results, you'll want to use a sustained-release preparation.
  • Avoid drinking alcohol, or at least limit your alcoholic drinks to one per day.
  • Avoid electromagnetic fields as much as possible. Even electric blankets may increase your cancer risk.
  • Avoid synthetic hormone replacement therapy, especially if you have risk factors for breast cancer. Many forms of breast cancer are estrogen-fueled, and according to a study published in the Journal of the National Cancer Institute, breast cancer rates for women dropped in tandem with decreased use of hormone replacement therapy. (There are similar risks for younger women who use oral contraceptives. Birth control pills, which are also comprised of synthetic hormones, have been linked to cervical and breast cancers.) If you are experiencing excessive menopausal symptoms, you may want to consider bioidentical hormone replacement therapy instead, which uses hormones that are molecularly identical to the ones your body produces and do not wreak havoc on your system. This is a much safer alternative.
  • Avoid BPA, phthalates, and other xenoestrogens. These are estrogen-like compounds that have been linked to increased breast cancer risk.
  • Make sure you're not iodine deficient, as there's compelling evidence linking iodine deficiency with certain forms of cancer. Dr. David Brownstein, author of the book Iodine: Why You Need It, Why You Can't Live Without It, is a proponent of iodine for breast cancer. It actually has potent anticancer properties and has been shown to cause cell death in breast and thyroid cancer cells. For more information, I recommend reading Dr. Brownstein's book. I have been researching iodine for some time ever since I interviewed Dr. Brownstein, as I do believe that the bulk of what he states is spot on. However, I am not at all convinced that his dosage recommendations are correct. I believe they are far too high.
  • Avoid charring your meats. Charcoal or flame-broiled meat is linked with increased breast cancer risk. Acrylamide—a carcinogen created when starchy foods are baked, roasted, or fried—has been found to increase cancer risk as well.


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