Largest, Longest Study on Mammograms Again Finds No Benefit
February 26, 2014 By Dr. Mercola
An annual mammogram is the conventional go-to “prevention” strategy for breast cancer. But researchers increasingly agree that mammography is ineffective at best and harmful at worst.
Unfortunately, breast cancer is big business, and mammography is one of its primary profit centers. This is why the industry is fighting tooth and nail to keep it, even if it means ignoring science.
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.
The latest study to reach this conclusion is also one of the longest and largest. As reported by the New York Times: “One of the largest and most meticulous studies of mammography ever done, involving 90,000 women and lasting a quarter-century, has added powerful new doubts about the value of the screening test for women of any age.
It found that the death rates from breast cancer and from all causes were the same in women who got mammograms and those who did not. And the screening had harms: 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.”
Where’s the Wisdom in Using a Cancer Screen That Causes Cancer?
Besides the harm caused by overtreatment, the wisdom of radiating your breasts year after year, for decades, is questionable at best, considering the fact that ionizing radiation can cause cancer.
Results published in the British Medical Journal2 (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.”
I’ve warned against the use of routine mammograms for years, despite vehraement attacks from the industry. In the final analysis, it’s been worth the legal fees I’ve had to pay to defend myself against skeptics over the years, as ever-mounting research repeatedly confirms my stance. At this point, the controversy is pretty much settled—at least if you take the published research into account.
Biggest Mammography Study to Date Finds No Benefit
The featured study, published in the British Medical Journal (BMJ),3 included a five-year screening period, with a total follow-up period of 25 years. 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 attributable to over-diagnosis. As previously explained by Dr. Otis Webb Brawley, chief medical officer of the American Cancer Society, the term “overdiagnosis” in cancer medicine refers to:4
“…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.”
The authors of the featured study concluded that:
5 “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.”
More Studies Disputing the Value of Routine Mammograms
The rate of overdiagnosis (22 percent) is virtually identical to that found in a 2012 Norwegian study,6 which found that as many as 25 percent of women are consistently overdiagnosed with breast cancer that, if left alone, would never have caused them any harm. Other studies that support the findings of the featured study include the following:
- In 2007, the Archives of Internal Medicine7 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)
- Similar results were found in a 2009 meta-analysis by the Cochrane Database Review,8 which found that breast cancer screening led to a 30 percent rate of overdiagnosis and overtreatment, which actually increased the 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 treated unnecessarily.
- Another Norwegian study,9 published in 2010, concluded that 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 as a result of the screening.
- Research published in The Lancet Oncology in 2011,10 described the natural history of breast cancers detected in the Swedish mammography screening program between 1986 to 1990, involving 650,000 women. Since breast lesions and tumors are aggressively treated and/or removed before they can be determined with any certainty to be a clear and present threat to health, there has been little to no research on what happens when they are left alone.
This study however, 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.
False Negatives—Another Hazard of Mammography
Besides false positives that lead to unnecessary treatments, there’s also the risk of getting a false negative, meaning that a life-threatening cancer is missed. According to the National Cancer Institute (NCI), mammograms miss up to 20 percent of breast cancers that are present at the time of screening. If a mammogram detects an abnormal spot in your breast, the next step is typically a biopsy. This involves taking a small amount of tissue from your breast, which is then looked at by a pathologist under a microscope to determine if cancer is present.
The problem is that early stage cancer like ductal carcinoma in situ (DCIS) can be very hard to diagnose, and there are no diagnostic standards for it. Furthermore, pathologists doing the readings are not required to have specialized expertise. As Dr. Shahla Masood, the head of pathology at the University of Florida College of Medicine in Jacksonville, told the New York Times in 2010:11
“There are studies that show that diagnosing these borderline breast lesions occasionally comes down to the flip of a coin.”
It’s important to realize that a negative mammogram cannot be equated with a clean bill of health. All a negative mammogram can tell you is that IF you do have cancer, it hasn’t grown large enough yet to be detected. This is particularly true for women with dense breast tissue. Forty-nine percent of women have high breast tissue density,12 and mammography’s sensitivity for dense breasts is as low as 27 percent13—meaning 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.
Women Faced with Increasingly Confusing Choices
The featured study has reignited the debate about whether or not an annual mammogram is a wise choice for most women. Complicating matters further is the fact that, over the past few years, a number of medical groups have created divergent recommendations with regards to if and when you should get a mammogram.
In November of 2009, the US Preventive Services Task Force, a federal advisory board, revised their cancer screening recommendations,14 saying annual mammograms weren’t necessary for women under age 50 and that screenings were recommended only every two years after that. The panel based the new guidelines on data indicating that mammography does more harm than good when used on younger women.
Many cancer groups refused to adopt these guidelines however, and still recommend women over the age of 40 to be screened annually. This includes the American Cancer Society, the National Cancer Institute, and the American College of Radiology.
In 2011, the American Congress of Obstetricians and Gynecologists (ACOG) threw women for yet another loop when it changed its guidelines to include MORE screening compared to its previous recommendations. ACOG had previously recommended annual mammograms starting at age 50. As of 2011, it began urging women to get an annual mammogram starting at the age of 40. As stated by the New York Times:15
“[T]he days of one-size-fits-all screening may be ending. Now patients and their doctors will face much more nuanced choices, based on each woman’s risk for breast cancer and her feelings about the prospect of unnecessary treatment. ‘The balance between benefits and harms is more and more up in the air,’ said Dr. Russell P. Harris, a professor of medicine at the University of North Carolina, Chapel Hill. ‘Reasonable people will disagree.'”
3D Tomosynthesis—The Crazy Alternative That Increases Your Risks Even Further
Unfortunately, instead of admitting the flaws and inherent dangers of mammography, the industry unveiled a “new and improved” type of mammogram in 2011 called 3D tomosynthesis, which actually exposes you to even HIGHER doses of radiation than a standard mammogram. What’s worse, they also recommend you continue receiving your traditional 2D mammogram when you get tomosynthesis, thereby multiplying your radiation exposure even further. According to surgeon Dr. Susan Love,16 tomosynthesis exposes you to about twice the amount of radiation compared to a standard mammogram.
According to one 2010 study,17 annual screening using standard digital or screen-film mammography on women aged 40–80 years is associated with an induced cancer incidence and fatal breast cancer rate of 20–25 cases per 100, 000. Meaning, annual mammograms CAUSE 20-25 cases of fatal cancer for every 100,000 women getting the test. Further increasing—perhaps doubling—the number of fatal breast cancer caused as a direct result of the screening procedure itself can hardly be called progress.
Article written by Dr. Mercola. To read this article and numerous other articles linked to Mammography, visit Dr.Mercola.com