Time to Talk Frankly About Cancer
donderdag, 18 september 2014 - Categorie: Artikelen
Bron: www.counterpunch.org/2014/09/17/time-to-talk-frankly-about-cancer/ .
17 sept. 2014
by KRISTINE MATTIS
In a September 2014 article in the Journal of the American Medical Association, Dr. Mary-Claire King – the woman who first discovered the so-called breast cancer gene BRCA1 – and her colleagues suggested that all women should undergo routine medical screening for this gene as well as BRCA2. Of course, it seems reasonable that women should know if they carry these mutant allele forms of these genes, because the mutant genes confer a greater risk for breast cancer and ovarian cancer in women who have the mutants than in women who do not.
There has been some discussion about Dr. King’s proposal in newspapers and on the radio, but the dialogue inevitably has two tremendous pieces of the cancer puzzle missing: cause and prevention. In fact, too much cancer information tends to be myopic, neglecting to mention essential elements of the global portrait of cancer etiology. Conventional wisdom about cancer tends to end up promulgating misinformation and misinterpretations, not sound science. Dr. King’s piece, as well the highly publicized bi-annual Stand Up to Cancer celebrity charity telethon, which raises money for cancer treatment, have done nothing to provide more clear information to the public that could help avert this all-too-common but potentially highly preventable scourge that has caused suffering upon and taken the lives of so many of our friends and family.
First and foremost, it is important to emphasize that cancer is NOT heritable. Actor Piece Brosnan proclaimed on the aforementioned telethon that cancer was a “wretched inherited disease.” It certainly is wretched, but is not inherited nor is it really a single disease.
Most inherited diseases such as cystic fibrosis, Tay-Sachs, or Huntington’s disease are relatively rare, because on a population level, the processes of evolution and natural selection promote the disappearance of the genes that produce the disease, unless those genes also confer some benefit. Some inherited diseases are less rare because of their unique side-benefits. Sickle-cell anemia, for example, can confer a beneficial trait, because those who carry only one allele (one of the two in a gene pair that is inherited from mother and father) for sickle-cell do not have the harsh symptoms of the disease, but do instead have an increased resistance to malaria.
In contrast, the BRCA1 and BRCA2 mutant genes do not cause cancer; they merely make it more difficult for your cells to repair damage done to your DNA. When your cells are exposed to a cancer-causing agent (i.e., a carcinogen) such as ionizing radiation, certain natural and synthetic compounds, certain viruses, and some endocrine disrupting chemicals, to name a few, they have mechanisms to repair the damage that agent may cause to your DNA. But if the damage is too severe or widespread, or if the cell lacks that mechanism for repair, as in the case of those who have the “breast-cancer genes,” your risk of contracting cancer is increased.
It is basic scientific knowledge that cancer is not inheritable, but in light of the discovery of various genes that confer increased susceptibility to cancer, this fact is not always well understood by the population at large. Only 5-10% of people who contract any type of cancer have any sort of inherited genetic susceptibility. Therefore, the focus on inherited mutant alleles leaves out the majority 90-95% of people suffering from cancer. While it is true that the minority 5-10% who do have these mutant alleles have a much greater risk for disease than the rest of us, they do not have an inherent “predisposition” to cancer. Labeling these genes as “cancer genes” or even “genetic predispositions” is a terrible misnomer. These genes increase susceptibility to cancer when exposed to cancer causing agents.
In Dr. King’s article, she mentions that the risk of developing cancer when you have a genetic susceptibility is significantly higher for women born more recently than for women born long ago, and that this phenomenon has been confirmed in numerous studies. Indeed, women born today who have the BRCA1 or BRCA2 gene have two to three times as much risk for developing cancer as women of previous generations. This, again, should make it clear that these genes do not themselves cause cancer. But Dr. King explains this trend away by saying it is due to earlier ages of menarche and later ages of childbearing now. Once again, while these occurrences are correlated to increased risk for cancer, they are not in and of themselves causes of cancer. The cause related to early menarche and late childbearing probably is due to increased exposure to estrogens, which can indirectly influence a cascade of cancer-causing cellular events. More importantly, the reason for earlier and earlier ages of menarche is most likely to due our increased exposures to synthetic estrogens, not better nutrition, as Dr. King postulates. But passing off these two risk factors off as primary causes of the increase in breast cancers incidences is disingenuous.
More and more we are learning that many of the over 80,000 synthetic chemicals that humans have constructed over the course of the last century or so not only directly cause DNA mutations that lead to cancer, but mimic estrogen in our bodies, which indirectly lead to cancer. These chemicals are in food we eat, the air we breathe, the water we drink, and the endless industrial products we produce and consume. They are quite often the products and processes of industry, and are not essential to maintain a comfortable life on this planet. In addition, the radiation we receive from sources such as diagnostic exams via x-ray, CT scan, and other radiologic medical procedures are being shown to contribute to excess cancers. For example, the UK Committee on Medical Aspects of Radiation in the Environment recently stated that one out of 2000 people will contract cancer due to abdominal CT scans – otherwise known as an iatrogenic cancer. This may seem a fairly small risk, unless you are that one person who has had an unnecessary CT scan and then is diagnosed with a preventable cancer because of it. Furthermore, scientists are finding more and more evidence that non-ionizing radiation, such as the radiofrequency radiation transmitted by cell phones, cell phone towers, wireless internet, and wireless water and electrical metering devices, is also a possible carcinogen. (The World Health organization places it in the same carcinogen class as the human papillomavirus.) The ubiquity of carcinogens and the ubiquity of our exposure to them, synergistically and cumulatively, is far more likely to be the cause of our plague of cancer diagnoses; it is far more likely that because women are more exposed to these carcinogens than in previous generations, the risk for women who have the BRCA mutant alleles is greater than in previous generations of women. Moreover, the risk for women who do not carry the BRCA mutant alleles and who are better able to repair the DNA in their cells, while relatively lower, is also increasing in more recent generations.
But for some reason, this plain and simple fact that exposure to carcinogens can and does lead to cancer is always absent in the medical discussion of cancer. Part of the reason may be that medical practitioners are rarely, if ever, versed in environmental health, so they are not even educated about environmental toxicology and the myriad diseases caused by environmental exposures. But part of the reason is likely political and economic. Real biological causes of cancer seem to be verboten because scientists and scholars who speak these truths are condemned, defamed, and discredited by the powerful industrial public relations machine, which has multi-billions of dollars worth of revenue to protect, as it maintains the businesses and industries that introduce so many of the carcinogenic products in our world.
Another important clarification in discussing cancer is that diagnosis does not equal prevention. In an Orwellian twist of double-speak, health care professionals have delineated different forms of “prevention” and have decided that the diagnosis and screening for cancer is what they deem “secondary prevention.” In truth, diagnosis is not prevention at all and should not be termed as such. But diagnosis is obviously necessary in a country where cancer afflicts more than 30% of the population. A problem when you combine diagnostic techniques that are in and of themselves carcinogenic, with people who have genetic susceptibilities to cancer, is that through the use of radiological diagnostics, the medical profession is inadvertently increasing the susceptibility of the already susceptible population even more. Consequently, when doctors propose that women with the BRCA1 and BRCA2 mutant alleles start mammograms sooner in life and have more mammograms than other women, they are thus exposing these women, whose cells do not have the right machinery to combat carcinogens, to even more carcinogens than the average person (since mammograms use radiation). Thus, if we are indeed to screen all women for the mutant BRCA alleles, we should at least be using ultrasound and MRI (which are harmless diagnostic procedures, as far a science currently understands) when vigilantly monitoring them for cancer, rather than increasing the carcinogen exposure in a population who are already inherently less able to deal with it.
What does all this mean for women who have the mutant alleles for breast and ovarian cancer susceptibility? Too often, the onus for protecting oneself from cancer is put on the victims of the disease. Doctors discussing the call for universal BRCA gene screening say that women can then know about their susceptibility and then embark on better diet and exercise regimens to help prevent the disease. Certainly, a good, clean, healthful diet of whole foods and a semi-rigorous and regular exercise routine are always to be applauded, but the idea that these lifestyle measures prevent cancer actually flies in the face of scientific evidence that is continually accumulating. The New York Times published an article in its April 21, 2014 edition entitled, “An Apple a Day, and Other Myths” in which they illuminated that the consensus among the tens of thousands of scientists who study cancer and diet is that “when it comes to cancer there was little evidence that fruits and vegetables are protective or that fatty foods are bad.”
When discussing cancer, the lack of conversation about our ubiquitous exposures to carcinogens is highly negligent. A few causes seem to be safe for conversation. We readily speak of the human papillomavirus (HPV) and the chemical benzopyrene, which is produced when food is burnt. Often, we do not even mention any sort of safe or acceptable levels of exposure to these organisms or chemicals; we assume that no level of exposure is necessary. But the tens of thousand of other chemicals, products, and pollutants that cause cancer, to which we are universally and often unnecessarily exposed, are rationalized as unproblematic at the levels with which we use them. Moreover, the acute scientific and medical focus on genetic susceptibilities in the minority of patients, instead of research into the etiology of cancer in the majority of patients, demonstrates that cause and prevention are not priorities. It also dooms us to failure in the fight against this disease. But that does not have to be. We can work to eliminate the underlying causes of cancer. Many of these processes and products are completely unnecessary in our lives and contribute to other global harms such as climate change. Until we can have a frank conversation about cancer that includes all of the primary elements contributing to the disease, additional screening for genetic susceptibility (for women who actually have access to health care – and many still do not) will be of little help and we will be even farther from combating this horrendous blight.
Kristine Mattis received her PhD from the Nelson Institute for Environmental Studies at the University of Wisconsin-Madison. As an interdisciplinary environmental scholar with a background in Biology and Earth System Science, her research focuses on environmental risk information.
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