Breast cancer screening with mammography protocols results in an increase in breast cancer mortality, according to long-term follow-ups in large-scale studies.
In a Swedish study of 60,000 women, 70 percent of the mammographically detected tumors weren't tumors at all. These "false positives" aren't just financial and emotional strains, they may also lead to many unnecessary and invasive biopsies. In fact, 70 to 80 percent of all positive mammograms do not, upon biopsy, show any presence of cancer.
At the same time, mammograms also have a high rate of missed tumors, or "false negatives." Dr. Samuel S. Epstein, in his book, The Politics Of Cancer, claims that in women ages 40 to 49, one in four instances of cancer is missed at each mammography. The National Cancer Institute (NCI) puts the false negative rate even higher at 40 percent among women ages 40-49. National Institutes of Health spokespeople also admit that mammograms miss 10 percent of malignant tumors in women over 50. Researchers have found that breast tissue is denser among younger women, making it difficult to detect tumors. For this reason, false negatives are twice as likely to occur in premenopausal mammograms.
Radiation exposure in known to cause genetic mutation in breast cells. It is also known to switch off the tumour suppressing gene. Now, new research from the Lawrence Berkeley National Laboratory in America (a US Government facility) has shown that radiation both changes the environment around breast cells, and increases the risks of mutation within them; a mutation that can be passed on in cell division.
This study showed that 4 to 6 weeks after exposure to radiation at a level below that of a screening mammogram, breast cells started to prematurely age. This resulted in their inability to send certain chemical messages into their immediate environment, which then filled with pre-cancerous mutated cells also from the radiation.
"Our work shows that radiation can change the microenvironment of breast cells, and this in turn can allow the growth of abnormal cells with a long-lived phenotype that have a much greater potential to be cancerous," said Paul Yaswen, a cell biologist and breast cancer research specialist with Berkeley Lab´s Life Sciences Division, adding "Many in the cancer research community, especially radiobiologists, have been slow to acknowledge and incorporate in their work the idea that cells in human tissues are not independent entities, but are highly communicative with each other and with their microenvironment."
The Myth of Early Diagnosis
It is also questionable whether screening mammograms can even provide genuine ´early diagnosis´ as is frequently claimed. A new blood test being developed in America and Nottingham, England will pick up on proteins developed by the very earliest ´rogue´ cells almost before a cancer has formed. In the press release the scientists claim that this is a good 4 years before a mammogram can show up a tumour. Apparently, a cancer makes about 40 divisions during its life, and mammograms cannot pick up a breast tumour until it is of a sufficient size, usually around 20 such divisions. So much for early diagnosis!
In Spring 2009, nine American scientists were so concerned by what they felt were distinctly dodgy practices at the Federal Drugs Agency, (FDA) they wrote to new President Obama, One of their main causes for concern was the FDA’s silence over the increasing knowledge of the risks associated with mammograms.
These concerns are part of a growing trend. Perhaps one of the most damning reports was a large scale study by Johns Hopkins published in 2008 in the prestigious Journal of the American Medical Association´s Archives of Internal Medicine (Arch Intern Med. 2008;168[21:2302-2303). In the Background to the research it was pointed out that breast cancer diagnosis rates increased significantly in four Scandanavian counties after women there began receiving mammograms every two years. Now, there will be those who will simply argue that this just shows the power of mammograms to find (diagnose) breast cancer. They may well be talking rubbish.
In the study looking at two large scale groups of women in Norway, one having a mammogram every two years for 6 years, the other just at the end, the researchers themselves went on to conclude that they cannot link the increased incidence of breast cancer diagnosis simply to more real cases being detected because the rates among regularly screened women were significantly higher than rates among women of the same age who only received a mammogram at the end of the same six year period.
There are therefore three possible logical conclusions:
- The women in the control group who had a mammogram only at the end of year six somehow had their breast cancers heal themselves – the cancer went away without treatment.
- Not all the women diagnosed with irregularities actually had a problem that became breast cancer
- The more breast cancer screening you have, the more your incidence of breast cancer diagnosis increases.
The research was by no means a small study and compared 119,472 women screened every two years, with an identical group of 109,784 who had none.
The researchers themselves went on to conclude that the findings "provide new insight on what is arguably the major harm associated with mammographic screening, namely, the detection and treatment of cancers that would otherwise regress."
That in itself is a truly important conclusion - the idea that if you leave a cancer alone (even if it has already had 20 divisions), the body can still heal itself.
But the conclusion that quite simply screening mammograms every two years cause an increase in cancers cannot be dismissed!
Many critics of mammography cite the hazardous health effects of radiation. In 1976, the controversy over radiation and mammography reached a saturation point. At that time mammographic technology delivered five to 10 rads (radiation-absorbed doses) per screening, as compared to 1 rad in current screening methods. In women between the ages of 35 and 50, each rad of exposure increased the risk of breast cancer by one percent, according to Dr. Frank Rauscher, then-director of the NCI.
According to Russell L. Blaylock, MD, one estimate is that annual radiological breast exams increase the risk of breast cancer by two percent a year. So over 10 years the risk will have increased 20 percent. In the 1960s and 70s, women, even those who received 10 screenings a year, were never told the risk they faced from exposure. In the midst of the 1976 radiation debate, Kodak, a major manufacturer of mammography film, took out full-page ads in scientific journals entitled About breast cancer and X-rays: A hopeful message from industry on a sober topic.
Despite better technology and decreased doses of radiation, scientists still claim mammography is a substantial risk. Dr. John W. Gofman, an authority on the health effects of ionizing radiation, estimates that 75 percent of breast cancer could be prevented by avoiding or minimizing exposure to the ionizing radiation. This includes mammography, x-rays and other medical and dental sources.
Since mammographic screening was introduced, the incidence of a form of breast cancer called ductal carcinoma in situ (DCIS) has increased by 328 percent. Two hundred percent of this increase is allegedly due to mammography. In addition to harmful radiation, mammography may also help spread existing cancer cells due to the considerable pressure placed on the woman's breast during the procedure. According to some health practitioners, this compression could cause existing cancer cells to metastasize from the breast tissue.
Cancer research has also found a gene, called oncogene AC, that is extremely sensitive to even small doses of radiation. A significant percentage of women in the United States have this gene, which could increase their risk of mammography-induced cancer. They estimate that 10,000 A-T carriers will die of breast cancer this year due to mammography.
The risk of radiation is apparently higher among younger women. The NCI released evidence that, among women under 35, mammography could cause 75 cases of breast cancer for every 15 it identifies. Another Canadian study found a 52 percent increase in breast cancer mortality in young women given annual mammograms. Dr. Samuel Epstein also claims that pregnant women exposed to radiation could endanger their fetus. He advises against mammography during pregnancy because "the future risks of leukemia to your unborn child, not to mention birth defects, are just not worth it." Similarly, studies reveal that children exposed to radiation are more likely to develop breast cancer as adults.
Navigating the Statistics
While the number of deaths caused by breast cancer has decreased, the incidence of breast cancer is still rising. Since 1940, the incidence of breast cancer has risen by one to two percent every year. Between 1973 and 1991, the incidence of breast cancer in females over 65 rose nearly 40 percent in the United States.
Some researchers attribute this increase to better detection technologies; i.e., as the number of women screened for breast cancer rises, so does the number of reported cases. Other analysts say the correlation between mammographic screening and increases in breast cancer is much more ominous, suggesting radiation exposure is responsible for the growing number of cases. While the matter is still being debated, Professor Sandra Steingraber offers ways to navigate these statistics. According to Steingraber, the rise in breast cancer predates the introduction of mammograms as a common diagnostic tool. In addition, the groups of women in whom breast cancer incidence is ascending most swiftly blacks and the elderly are also least likely to get regular mammograms.
The majority of health experts agree that the risk of breast cancer for women under 35 is not high enough to warrant the risk of radiation exposure. Similarly, the risk of breast cancer to women over 55 justifies the risk of mammograms. The statistics about mammography and women between the ages of 40 and 55 are the most contentious. A 1992 Canadian National Breast Cancer Study showed that mammography had no positive effect on mortality for women between the ages of 40 and 50. In fact, the study seemed to suggest that women in that age group are more likely to die of breast cancer when screened regularly.
Burton Goldberg, in his book, Alternative Medicine, recommends that women under 50 avoid screening mammograms, although the American Cancer Society encourages mammograms every two years for women ages 40 to 49. Trying to settle this debate, a 1997 consensus panel appointed by the NIH ruled that there was no evidence that mammograms for this age group save lives; they may even do more harm than good. The panel advises women to weigh the risks with their doctors and decide for themselves.
New Screening Technologies
While screening is an important step in fighting breast cancer, many researchers are looking for alternatives to mammography. Burton Goldberg totes the safety and accuracy of new thermography technologies. Able to detect cancers at a minute physical stage of development, thermography does not use x-rays, nor is there any compression of the breast. Also important, new thermography technologies do not lose effectiveness with dense breast tissue, decreasing the chances of false-negative results.
Some doctors are now offering digital mammograms. Digital mammography is a mammography system in which x-ray film is replaced by solid-state detectors that convert x-rays into electric signals. Though radiation is still used, digital mammography requires a much smaller dose. The electrical signals are used to produce images that can be electronically manipulated; a physician can zoom in, magnify and optimize different parts of breast tissue without having to take an additional image.
Breast thermography, which involves using a heat-sensing scanner to detect variations in the temperature of breast tissue, has been around since the 1960s. However, early infrared scanners were not very sensitive, and were insufficiently tested before being put into clinical practice, resulting in misdiagnosed cases.
Modern-day breast thermography boasts vastly improved technology and more extensive scientific clinical research.
In fact, the article references data from major peer review journals and research on more than 300,000 women who have been tested using the technology. Combined with the successes in detecting breast cancer with greater accuracy than other methods, the technology is slowly gaining ground among more progressive practitioners.