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Cancer Risk Factors



"The only way to keep your health is to eat what you don't want, drink what you don't like, and do what you'd druther not." - By Mark Twain

Today, heart disease, cancer, and stroke are the three major chronic, degenerative, killer diseases. They account for 58.7% of all deaths in the United States and 52.4% of all deaths in Canada. In 2004, cancer (29.5%) topped heart disease (22.9%) and became the leading cause of deaths in Canada.

Cancer is a disease of our genes (or DNA) and their proteins (see Understanding Cancer and Its Possible Treatments). It can take decades to develop. What explains the rising rates of cancer worldwide? Perhaps these are due to the toxic substances in our foods and environment (see Toxins Are Everywhere--I'm Not Kidding).


Living healthy life is a choice. Facing all known or possible risk factors, we can either choose to ignore or avoid them. 

As cancer doctor David B. Agus[8] has said: "If you come to me for help in treating advanced cancer detected late in the game, your game is likely to be over soon." So, be vigilant. Don't listen to critics; just get on with the prevention that needs to be done.

In this article, I'm going to list all general cancer risk factors.  You can also find risk factors associated with individual cancer in my other posts[9-11].

General Cancer Risk Factors
Nearly all cancers are caused by gene (or DNA) mutations or epigenetic alternations[12,13,16,17]. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired though errors in DNA replication (i.e., through living and aging), or are inherited, and thus present in all cells from birth. The former factors are controllable while the latter factors are uncontrollable.

Uncontrollable Risk Factors


Uncontrollable Risk Factors

Descriptions

Age


  • Mutations slowly accumulate over time and this explains why cancers most often attack people as they grow older.
  • Aging is the biggest risk factor of all for getting cancer.
Heredity



  • Heredity accounts for 5 to 10% of the risk for most common cancers.
    • Scientists conclude that "Inherited genetic factors make a minor contribution to susceptibility to cancer." They also found that environment plays the principal role among the causes of common cancers.
  • A family tree in which prostate, breast, colon, or ovarian cancer or malignant melanoma has occurred in first-degree relatives signals a 2 to 3 times greater chance of getting one of these cancers compared to those without this family history.
  • A smaller heredity risk is seen with kidney cancer, non-Hodgkin's lymphoma, pancreatic, stomach, and even lung cancer.
  • In contrast, heredity does not seem to play a role in adult leukemia or cancer of the cervix, uterine lining or bladder.
  • Keeping track of relatives who developed cancer, and at what ages, should be part of our own personal medical history.


Controllable Risk Factors


These controllable risk factors can be broadly grouped into chemical and biological carcinogens, environmental hazards, and lifestyles.

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Chemical Carcinogens

Carcinogenic chemicals work by messing with the molecules of DNA in our cells. The National Toxicology Program gathers information on potential carcinogens and conducts tests in their laboratories. Every two years they generate a report on carcinogens for Congress. The list, available on line, focuses mainly on chemical carcinogens.

Chemical Carcinogens

Descriptions

Benzopyrenes (part of the family of cancer-causing chemicals known as polycyclic aromatic hydrocarbons, or PAHs)
  • These are brown-black residues from high-temperature burning (i.e., char-grilled meats, dark residue of tobacco, incinerator exhaust, and belching smokestacks)
  • Experiments at Lawrence Livermore Laboratory showed that a well-toasted bread had 20% of the cancer-causing activity of a well-done hamburger.
Arsenic
  • Found in soils and even in foods[14]
Asbestos
  • Could cause fatal lung cancer
Aflatoxin
  • A toxic product of a mold called Aspergillus flavus, which grows on crops in warm, moist climates. Corn, cottonseed, and peanuts are favored for such moldy growth.
Radon
  • Naturally occurring gas. If inhaled, it can cause lung cancer.
  • Radon can be built up in poorly ventilated spaces such as basements or crawl space.


Biological Carcinogens

One in six cancers worldwide is caused by preventable or treatable infections, a new study finds[24]

Biological Carcinogens

Descriptions

Human Papillomavirus (HPV)

  • Cervical cancer has been linked to the human papilloma virus
  • As with other carcinogens, HPV is more likely to cause cancer when there are other associated factors, including co-infection with multiple strains of this virus or with other sexually transmitted diseases, including herpes, chlamydia, gonorrhea, and syphilis.
Hepatitis B, C

  • Chronic infection with either Hepatitis virus B or C increases the risk for liver cancer.
  • Hepatitis B is the lesser of the two viral evils, since it rarely goes on to cause chronic disease while hepatitis C has become a major trigger of liver cancer.
Helicobacter pylori

  • H. pylori causes most stomach ulcers which is also guilty of causing stomach cancer[13,15].
  • Research in Japan, where this cancer is fairly common, shows that treating stomach ulcers with antibiotics prevents about half of stomach cancers and also plays an important role in the cancer's treatment.
  • H. pylori bacterium, found in contaminated drinking water, takes hold of a vulnerable gastric lining and fosters chronic inflammation leading to injury and in some cases major ulceration.
Epstein-Barr

  • It is thought that some malignant transformations are due to viruses such as the Epstein-Barr virus, although this is currently restricted to just a few cancer types.


Environmental Hazards


Environmental Hazards

Descriptions

Stress
  • The stress of caring for a chronically ill family member, losing a spouse, marital strife, social isolation--all of these can depress components of the immune system.
  • Chronic stress depresses white cells that fight cancer and can interfere with DNA's ability to repair itself.
Smoking
  • Tar still reigning as number one among the environmental hazards causing the most cancer deaths in the United States and worldwide.
  • Smokers and people exposed to tobacco smoke age faster and die younger of heart disease and cancer.
  • Smoking escalates cell turnover, the risk of cell mutations, and the development of cancerous cells because of its damaging effects on the lining of the lungs.
  • The teen years are also the most dangerous time to take up smoking.
Ionizing radiation
  • Radiation's cancer-producing potential is directly related to cumulative, lifetime dose.
  • A 2005 report by the National Academy of Sciences on the health effects of small doses of radiation, a report incorporating nearly 15 years of new data on atomic bomb survivors in Japan, reinforces the idea that even tiny doses may add slightly to risk.
  • Women are more likely than men to get cancer, given equal doses. There is no truly established safe radiation level.
  • Ionizing radiation is dangerous just because it's ionizing. It rams into atoms with enough energy to knock one of their electrons clean out of its orbit circling the atomic nucleus. The result is a particularly nasty ion with DNA-mangling free radicals.
  • Laboratory experiments show that when DNA is bombarded by ionizing radiation, it mutates rapidly and becomes scrambled by breaks, sometimes so badly that the cell is forced to commit suicide.
  • Gamma rays, high-energy X-rays, are the most dangerous because they can invisibly, painlessly, and silently move through clothes and skin and penetrate deeply into the body.
  • About 20% of our lifetime exposure to ionizing radiation comes in the form of diagnostic radiology--from the chest film to the CT scan, the dental X-ray to the radioisotope scan.
  • The other 80% of our lifetime exposure to ionizing radiation is a consequence of natural radiation from the environment.
  • The FDA estimates that a single abdominal CT scan carries the radiation impact of 500 chest X-rays.
  • Physicist David Brenner and his colleagues point out that a 20-minute CT scan can deliver the same radiation exposure as if you were standing just a mile and a half from the atomic bomb explosion at Hiroshima.
  • The thyroid gland is very sensitive to radiation/  Although routine dental X-rays, chest X-rays and mammograms of today use much lower and safer amounts of radiation, some worry about this as a thyroid-damaging source.
    • Some professionals say to protect the thyroid people should wear a lead thyroid shield (and apron when possible) when undergoing these procedures block radiation reaching the thyroid gland, and to limit tests using X-rays to those that are absolutely necessary[5].
Non-ionizing radiation
Water Pollution
  • Many factors are responsible for water pollution, including the rising number of metro vehicles and electrical utilities that emit sulfur dioxide and nitrogen oxides, resulting in the acid rain that contaminates rivers, lakes, and other water supplies.
  • Pesticides[16] and herbicides also threaten the water supply.
  • Cancer and heart disease, as well as life-threatening illnesses, have been linked to polluted drinking water.
  • For instance, higher levels of cancer, particularly leukemia and lymphomas, are reported in Iowa, Nebraska, and Illinois. Farmers and farm workers are at greatest risk of exposure because of pesticides that filter into the drinking water.


Lifestyles

Lifestyles

Descriptions

Saturated fats
  • Linked to an increased risk of cancer of the colon, prostate, uterine lining, and possibly breast and pancreas.
High-salt diets and ones with lots of salt-preserved or nitrite-rich foods
  • Linked to stomach cancer

Very hot drinks or soups
  • Can increase the risk of cancer of the mouth, esophagus, and larynx
Excess alcohol
  • Linked to an increase in head and neck cancer and cancers of the liver and breast.
  • Excessive alcohol consumption is associated with more than 1.8 million deaths each year, including deaths from liver, oral, esophageal, breast, and colorectal cancers. Women should limit intake to no more than one drink a day, men to two drinks or less per day.
  • Women who consume two or more drinks a day increase their risk for breast cancer.
  • Heavy drinkers also are much more likely to suffer from cirrhosis, high blood pressure, mouth and throat cancer, bronchitis and pneumonia, and liver cancer, and they're at high risk of dying from accidents, suicide, and cardiac arrest.
  • People who consume more than 4 or 5 alcoholic drinks are likely to develop impaired memory and loss of mental ability as well.
Overdosing on red meat
  • Delivers a small risk for colon cancer
Lack of exercise
  • The link between reduced cancer risk and exercise has long been recognized for cancer of the colon, and there the connection is clear.
  • Gut motility is improved by moving around, and toxic waste is pushed along faster, giving gut mucosa less exposure to its carcinogens.
  • Women who exercise face lower rates of recurrence of a prior breast cancer.
  • Those who have less sedentary lives experience fewer cancers overall.
High calorie diet
  • The most popular theory is that fewer calories mean less oxidation is going on and therefore fewer destructive free radicals are floating around and doing damage to DNA.
  • There could also be a more direct connection to blood sugar. Consuming fewer calories overall results in fewer and less severe sugar spikes--the sudden jolts of sugar that call insulin into play. Cutting back on the glucose spikes should also cut back on blood levels of insulin-like growth factors. These are chemicals your body makes that stimulate cell proliferation and block apoptosis. High levels of these growth factors have been associated with breast, prostate, and colon cancer.
  • Another factor may be excess steroid hormones manufactured by fat cells, where the extra calories are stored. Fewer calories means less body fat, and obesity is a risk factor for certain cancers.
Sports Injury
  • Some individuals who've been diagnosed with cancer in particular locations of their bodies can link that specific area to a previous trauma or injury[8].
Pesticides in Food
  • Epidemiologic evidence demonstrates associations between early life exposure to pesticides and pediatric cancers, decreased cognitive function, and behavioral problems[22].
Pesticides in Food
  • Epidemiologic evidence demonstrates associations between early life exposure to pesticides and pediatric cancers, decreased cognitive function, and behavioral problems[22].
Obesity
  • Tumors of the colon, prostate, breast, uterus, kidney, and esophagus seem to disproportionately hit those lugging around too many extra pounds.
  • In 1982, a study conducted by the American Cancer Society, showed that cancer mortality increased as BMI (body mass index) increased over 30.
  • The American Cancer Society blames elevated BMI for about 20% of female and 14% of male cancer deaths.
  • National Cancer Institute experts concluded that obesity is associated with cancers of the colon, breast (postmenopausal), endometrium, kidney, and esophagus.
  • 42% of those diagnosed with breast and colon cancers are obese.
  • Of all gallbladder surgery, 30% is related to obesity.
Overuse of antibiotics and other medications 
  • A study published in the JAMA provides evidence that the use of antibiotics is associated with increased risk of breast cancer[25].
  • As Dr. Fuhrman said in [26]:
    • I remember the first pharmacology lecture I heard in medical school, when the professor emphasized, "Make no doubt about it: all drugs are toxic and can even hasten one's death. ... Couple our nutrient-poor diet—and the resultant immune system weaknesses, leading to frequent illness—with the use and overuse of medications, including antibiotics, vaccines, and immunosuppressive drugs for autoimmune diseases, and we have a good reason for the explosion in cancer rates over the last seventy years.

References

  1. "Healthy Aging for Dummies" by Murphy E. Smith
  2. "Breast Cancer-The Complete Guide" by Yashar Hirshaut, MD, FACP and Peter I. Pressman, MD, FACS
  3. "Living Time--Faith and Facts to Transforjavascript:void(0)m Your Cancer Journey" by Bernadine Healy, M. D.
  4. "Anti-Cancer--A New Way of Life" by David Servan-Schreiber, MD, PhD.
  5. The Increase in Thyroid Cancer
  6. Cancer prevention tips (EWG)
  7. How to reduce your risk of cancer
  8. "The End of Illness" by David B. Agus, MD
  9. Higher Esophageal Cancer Risk — If You Blush Easily With Drinking
  10. Colon Cancer and Its Prevention
  11. Understanding Cancer and Its Possible Treatments
  12. Epigenetics (Wikipedia)
  13. Methylation subtypes and large-scale epigenetic alterations in gastric cancer
  14. Arsenic in your food
  15. 我国医学团队掌握新胃癌特征 有助治疗此绝症
  16. DNA methylation alterations in response to pesticide exposure in vitro 
    • The present study provides evidence to support the hypothesis that pesticide-induced cancer may be mediated in part by epigenetic mechanisms
  17. DNA Methylation and Cancer
  18. Oncology.com
  19. Pesticides used in South American GMO-based agriculture: A review of their effects on humans and animal models
  20. Birth defects caused by glyphosate, Andres Carrasco (Talked at UC Irvine) 
  21. Glyphosate-Based Herbicides Produce Teratogenic Effects on Vertebrates by Impairing Retinoic Acid Signaling
  22. Nation's Pediatricians Warn Against Pesticides in Food
  23. Nobel laureate James Watson claims antioxidants in late-stage cancers can promote cancer progression
  24. Infection Causes 1 in 6 Cancers Worldwide
  25. Velicer CM, Heckbert SR, Lampe JW, et al.  Antibiotic use in relation to the risk of breast cancer.  JAMA 2004; 291(7): 827-35.
  26. Super Immunity by Joel Fuhrman, M.D.
  27. 10 Cancer Symptoms You Likely Ignore
  28. Asian Fund for Cancer Research Limited

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