By Dr. Mercola
Do annual mammograms save lives?
Several studies over the past few years have concluded that mammograms do not save lives, and may actually harm more women than they help, courtesy of false positives, overtreatment, and radiation-induced cancers.
According to research1 published in 2010, the reduction in mortality as a result of mammographic screening was so small as to be nonexistent — a mere 2.4 deaths per 100,000 person-years were spared.
Another study2 published in The Lancet Oncology in 2011 demonstrated, for the first time, that women who received the most breast screenings had a higher cumulative incidence of invasive breast cancer over the following six years than the control group who received far less screenings.
Now, researchers from Harvard and Dartmouth have published a paper3 in which they present similar conclusions.
Mammograms Have No Impact on Breast Cancer Mortality
After analyzing cancer registry data from 16 million women in 547 counties across the United States, they found “no evident correlation between the extent of screening and 10-year breast cancer mortality.”
The researchers concluded that mammograms primarily find small, typically harmless, or non-lethal tumors, leading to widespread overdiagnosis.
As explained by Dr. Otis Webb Brawley, chief medical officer of the American Cancer Society and author of the book, How We Do Harm, the term "overdiagnosis" in cancer medicine refers to:
"...a tumor that fulfills all laboratory criteria to be called cancer but, if left alone, would never cause harm. This is a tumor that will not continue to grow, spread, and kill. It is a tumor that can be cured with treatment but does not need to be treated and/or cured."
Also, echoing results found in 2011, higher screening rates were associated with higher incidence of breast cancer. As reported by The LA Times:4
“For every 10-percentage-point increase in screening rates, the incidence of breast cancer rose by 16 percent... That worked out to an extra 35 to 49 breast cancer cases for every 100,000 women...
The researchers also examined breast cancers according to their stage at diagnosis, a marker of a tumor’s aggressiveness. More screening was associated with a higher incidence of early-stage breast cancers but no change for later-stage tumors, according to the study.
How can this be?
‘The simplest explanation is widespread overdiagnosis, which increases the incidence of small cancers without changing mortality,’ the study authors wrote. ‘Even where there are 1.8 times as many cancers being diagnosed, mortality is the same.’”
To Screen or Not to Screen?
Clearly, the issue of breast cancer screening using mammography can be a deeply emotional one. Virtually all discussions relating to cancer are. A recent article in Forbes Magazine5 paints a vivid picture of most women’s fears, and warns of the dangers of not getting diagnosed in time.
While it needs to be an individual choice, I believe it can be valuable to take a step back and look at the big picture, which includes population-based statistics such as those presented above.
It’s also well worth investigating all available options and, of course, weigh the risks and benefits associated with each. As reported by Care2:6
“[The] study authors... point to a balance of benefits and harms and believe mammography is likely most favorable when directed at women who are at high risk — not too rarely and not too frequently.
They also believe watchful waiting, rather than immediate active treatment, is probably a good option in some cases.”
A main objection to mammography is the fact that it uses ionizing radiation to take images of your breasts, and it’s a well-established fact that ionizing radiation can cause cancer.
So the idea that the “best” way for you to avoid dying from cancer is to expose yourself to cancer-promoting radiation at regular intervals for decades on end (in order to catch the cancer early) really falls short on logic — especially since there are non-ionizing radiation imaging techniques available.
Results published in the British Medical Journal7 (BMJ) in 2012 show that women carrying a specific gene mutation called BRCA1/2 are particularly vulnerable to radiation-induced cancer.
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. The authors concluded that:
“The results of this study support the use of non-ionizing radiation imaging techniques (such as magnetic resonance imaging) as the main tool for surveillance in young women with BRCA1/2 mutations.”
Mammograms Do Not Reduce Mortality Beyond That of Physical Examination
Last year, one of the largest and longest investigations into mammography was published.8
It involved 90,000 women who were followed for 25 years, and it sent shockwaves through the medical industry when it reported that the death rates from breast cancer were virtually identical among women who got annual mammograms and those who did not.
Moreover, it found that mammography screening had harmful effects. As reported by The New York Times:9
“One in five cancers found with mammography and treated was not a threat to the woman’s health and did not need treatment such as chemotherapy, surgery, or radiation.”
At the outset of the study, the women, aged 40-59, were randomly assigned to receive either five annual mammography screens, or an annual physical breast examination without mammography.Over the course of the study, 3,250 of the women who received mammography were diagnosed with breast cancer, compared to 3,133 in the non-mammography group.
Of those, 500 women in the mammography group, and 505 in the control group, died from the disease. However, after 15 years of follow-up, the mammography group had another 106 extra cancer diagnoses, which were attributed to overdiagnosis. According to the authors:10
“Annual mammography in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care when adjuvant therapy for breast cancer is freely available. Overall, 22 percent of screen detected invasive breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial.”
The rate of overdiagnosis (22 percent) is virtually identical to that found in a 2012 Norwegian study,11 which found that as many as 25 percent of women are consistently overdiagnosed with breast cancer that, if left alone, would cause no harm. Other studies that have come to similar conclusions include the following:
- In 2007, the Archives of Internal Medicine12 published a meta-analysis of 117 randomized, controlled mammogram trials. Among its findings: rates of false-positive results are high (20-56 percent after 10 mammograms)
- A 2009 meta analysis by the Cochrane Database review13 found that breast cancer screening led to a 30 percent rate of overdiagnosis and overtreatment, which increasedthe absolute risk of developing cancer by 0.5 percent. The review concluded that for every 2,000 women invited for screening throughout a 10 year period, the life of just ONE woman was prolonged, while 10 healthy women were underwent unnecessary treatment.
Know the Signs and Symptoms of Breast Cancer
Mammograms can also miss the presence of cancer. According to the National Cancer Institute (NCI), mammograms miss up to 20 percent of breast cancers present at the time of screening. Your risk for a false negative is particularly great if you have dense breast tissue, and an estimated 49 percent of women do.14 Mammography's sensitivity for dense breasts is as low as 27 percent,15 which means that about 75 percent of dense-breasted women are at risk for a cancer being missed if they rely solely on mammography. Even with digital mammography, the sensitivity is still less than 60 percent.
Considering the mortality rate from breast cancer is virtually identical whether you get an annual mammogram or an annual physical breast exam, it suggests physical examination can go a long way toward detecting a potential cancer. It certainly makes sense to familiarize yourself with your breasts and the signs and symptoms of breast cancer.16,17 If you notice any of the following symptoms, be sure to address it with your doctor, even if you’re not due for an annual checkup yet.
Lump in the breast (keep in mind that breast lumps are common, and most are not cancerous) Dimpling of the breast surface, and/or “orange peel” skin texture Pain or unusual tenderness or swelling in the breast Visible veins on the breast Retracted nipple Change in size or shape of the breast Nipple discharge Enlarged lymph nodes (located in the armpit) Vaginal pain Unintentional weight loss
Optimize Your Vitamin D for Breast Cancer Prevention
While detection and diagnosis of breast cancer is certainly important as early treatment has a greater chance of success, prevention is really key, and here you can wield a lot of power over your own destiny. In the largest review of research into lifestyle and breast cancer, the American Institute of Cancer Research estimated that about 40 percent of US breast cancer cases could be prevented if people made wiser lifestyle choices. I believe that is a very conservative estimate.
It’s likely that 75 percent to 90 percent of breast cancers could be avoided by strictly applying the recommendations below, especially when done in combination, as part of an overall healthy lifestyle. Optimizing your vitamin D level alone has been shown to reduce your chances of breast cancer by at least 50 percent and double your chances of surviving breast cancer should you receive a breast cancer diagnosis.
Vitamin D influences virtually every cell in your body and is one of nature's most potent cancer fighters. It’s actually able to enter cancer cells and trigger apoptosis (cell death). Vitamin D also works synergistically with every cancer treatment I'm aware of, with no adverse effects. The average vitamin D level found in American breast cancer patients18 is 17 ng/ml, a far cry from a more optimal 40-50 ng/ml.
So please, be sure to regularly monitor your vitamin D levels and take whatever amount of vitamin D3 you need to maintain a clinically relevant level. (Remember you also need vitamin K2 if you’re taking an oral vitamin D supplement instead of getting regular sun exposure.)
Other Breast Cancer Prevention Tips
Other important lifestyle considerations that can help reduce your chances of breast cancer include the following:
Eat REAL Food A key dietary principle for optimal health and disease prevention is to eat real food. Choose fresh, organic, preferably locally growth foods. That also means avoiding all types of processed foods, which can contain any number of health harming ingredients, from refined sugar, processed fructose, genetically engineered ingredients, carcinogenic pesticides, and tens of thousands of food additives that have not been tested for safety.
Refined sugar is detrimental to your health in general and promotes cancer. As a general guideline, limit your total fructose intake to less than 25 grams daily. If you have cancer or are insulin resistant, you would be wise to restrict it to 15 grams or less.
Consider reducing your protein intake to one gram per kilogram of lean body weight. Replace the eliminated protein and carbs with high-quality fats, such as organic eggs from pastured hens, high-quality meats, avocados, and coconut oil. There's compelling evidence that a ketogenic diet helps prevent and treat many forms of cancer.
Also consider adding more cancer-fighting foods, herbs, and spices to your diet, such as broccoli. To learn more about how anti-angiogenetic foods fight cancer, please see our previous article: “Dramatically Effective New Natural Way to Starve Cancer and Obesity.”
Get plenty of natural vitamin A Vitamin A may also play a role in helping prevent breast cancer.19 It's best to obtain it from vitamin A-rich foods, rather than a supplement. Your best sources are organic egg yolks, raw butter, raw whole milk, and beef or chicken liver.
Beware of supplementing as there's some evidence that excessive vitamin A can negate the benefits of vitamin D. Since appropriate vitamin D levels are crucial for your health in general, not to mention cancer prevention, this means that it's essential to have the proper ratio of vitamin D to vitamin A in your body.
Ideally, you'll want to provide all the vitamin A and vitamin D substrate your body needs in such a way that your body can regulate both systems naturally. This is best done by eating colorful vegetables (for vitamin A) and by exposing your skin to appropriate amounts sunshine every day (for vitamin D).
Get sufficient amounts of iodine Iodine is an essential trace element required for the synthesis of hormones, and the lack of it can also cause or contribute to the development of a number of health problems, including breast cancer. This is because your breasts absorb and use a lot of iodine, which they need for proper cellular function. Iodine deficiency or insufficiency in any of tissue will lead to dysfunction of that tissue, and tumors are one possibility.
However, there's significant controversy over the appropriate dosage, so you need to use caution here. There's evidence indicating that taking mega-doses, in the tens of milligram range may be counterproductive. One recent study suggests it might not be wise to get more than about 800 mcg of iodine per day, and supplementing with as much as 12-13 mg (12,000-13,000 mcgs) could potentially have some adverse health effects.
Nourish your gut Optimizing your gut flora will reduce inflammation and strengthen your immune response. Researchers have found a microbe-dependent mechanism through which some cancers mount an inflammatory response that fuels their development and growth.
They suggest inhibiting inflammatory cytokines might slow cancer progression and improve the response to chemotherapy. Adding naturally fermented food to your daily diet is an easy way to prevent cancer or speed recovery. You can always add a high-quality probiotic supplement as well, but naturally fermented foods are the best.
Avoid xenoestrogens Xenoestrogens are synthetic chemicals that mimic natural estrogens. They have been linked to a wide range of human health effects, including reduced sperm counts in men and increased risk of breast cancer in women. There are a large number of xenoestrogens, such as bovine growth hormones in commercial dairy, plastics like bisphenol-A (BPA), phthalates, and parabens in personal care products, and chemicals used in non-stick materials, just to name a few. 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 breast cancer risk as well. 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 cancerous cells. Drink a quart of organic green vegetable juice daily Review my juicing instructions for more detailed information. Get plenty of high quality animal-based omega-3 fats Omega-3 deficiency is a common underlying factor for cancer. Take curcumin This is the active ingredient in turmeric and in high concentrations can be very useful in the treatment of breast cancer. It shows immense therapeutic potential in preventing breast cancer metastasis.20 To learn more about its use for the prevention of cancer, please see my interview with Dr. William LaValley. Avoid drinking alcohol Or at least limit your alcoholic drinks to one per day. Improve your insulin and leptin receptor sensitivity Eating a whole food diet low in added sugars is key. Exercising regularly will also promote optimal insulin and leptin sensitivity Avoid wearing underwire bras There is intriguing data suggesting metal underwire bras increase your breast cancer risk. Avoid electromagnetic fields Items such as electric blankets and cell phones can be particularly troublesome and increase your cancer risk. Definitely avoid stashing your phone in your bra as you go about your day.