| ||Cancer: Risk Factors - An Overview||
Charles Simone B. MD ©
Atherosclerosis and Cancer
Atherosclerosis and its many complications are the most common cause of death in the United States. Atherosclerosis, commonly called ''hardening of the arteries," is a disease that narrows the inside diameter of the artery. This narrowing restricts the blood flow beyond the narrowed portion, therefore less oxygen can be delivered to those tissues by the red blood cells. Death of tissues occurs when they receive little or no oxygen. The less oxygen, the more dead tissue. Pain is a symptom of either very low oxygen supply to tissues or outright death of tissues. This is why a person having a "heart attack" is in a lot of pain: some tissues are dying and others are not receiving enough oxygen. What does atherosclerosis have to do with cancer? Well, cancer may be responsible for the development of heart and vessel disease in a way, and conversely high blood pressure (a form of blood vessel disease) may lead to the development of cancer under certain circumstances.
The first step in the formation of a narrowed artery is the manufacture of cells (smooth muscle cells) which line the inside of the artery. Then cholesterol gets deposited in these cells after they have increased in number. The increased cells together with cholesterol is called a plaque. There is good evidence that these cells come from a single cell, that is, they are cloned from one common cell. Cloning is a form of cancer. (30) This situation can be produced in chickens by feeding. them carcinogens (benzo(a)pyrene and dimethylbenzanthracene), chemical substances that produce cancer. These particular carcinogens cause an increase in the number and rate of formation of plaques without altering the blood level of cholesterol. In humans, these types of carcinogens (hydrocarbons) are carried by certain proteins (low density lipoproteins) which also carry cholesterol. More curiously, an enzyme called aryl hydrocarbon hydroxylase, present in cells of the inner walls of arteries, can activate hydrocarbon carcinogens to start proliferating the lining cells. (31) Therefore, if we eat food contaminated with these hydrocarbons or are otherwise exposed to them so that they get into our bloodstream, atherosclerosis may begin to develop. Of course this is just one of many factors involved in the development of atherosclerosis.
R.W. Pero and colleagues have shown a relationship between high blood pressure and cancer. (32) The study shows that the higher the blood pressure and the older the person, the more alterations of DNA that occur in cells. The more abnormal the DNA content of a cell, the snore often it will lose control and develop into a cancer. There is some evidence that people with high blood pressure have an increased risk of developing breast cancer, (33) colon cancer, lung cancer, and other cancers.
Hormonal Risk Factors
Hormones influence a cell's growth and development, so if there is an excess or deficit of hormones in the body, then cells will not function properly and may grow abnormally or aberrantly and become cancer cells.
Women who have never been pregnant have a higher risk of developing breast cancer than women who do have children; and women who become pregnant before age 20 have a reduced risk. Women whose mothers or other close relatives have breast cancer have three times the normal risk of getting breast cancer. Women who do not menstruate during their lifetime have a three to four times higher risk of developing breast cancer after the age of 55. A lower risk of breast cancer is seen in women whose ovaries cease to function or are removed surgically before age (35).
There has been considerable controversy over whether oral contraceptives can cause breast and liver cancer. Many studies seem to indicate that hormones used in birth control pills are a risk factor for breast or liver cancer. (35,36) Estrogens in these oral contraceptives can cause benign liver growths as well, which can bleed extensively and cause problems related to bleeding.
Daughters of women who received DES (diethylstilbestrol) therapy during pregnancy have developed cancer of the cervix and vagina. Sons of women who took DES have a higher risk of developing cancer of the testicles because DES causes urinary tract abnormalities including undescended testicles, which, if not corrected surgically before age 6, can develop into cancer of the testicles. (37) Furthermore, women exposed to these same synthetic estrogens in adult life have a higher risk of developing cancer of the cells that line the inside of the uterus (endometrial cancer). Male hormones can predispose to both benign and malignant liver tumors.
Obesity is directly correlated with breast cancer (38-41) and endometrial cancer. (42)
Fibrocystic breast disease, a benign disease that affects 50 percent of all women sometime during their lives, probably represents a hormone imbalance. If a woman has had the disease over many years, she is at an increased risk of developing breast cancer. (43,44) Recently, fibrocystic breast disease has appeared to respond to certain nutrients and dietary modification.
Sexual-Social Risk Factors
Cancer of the cervix is associated with having sexual intercourse at an early age and with having multiple male sex partners. The earlier the age of the female when she first has sexual intercourse, and the greater the number of male partners she has, the higher is her risk of getting cancer of the cervix. Sexual intercourse with uncircumcised male partners may also contribute to a woman's risk of developing cervical cancer.
Cancer of the penis is a very rare disease in the United States. There is almost universal agreement that one primary risk factor is responsible for this cancer--poor hygiene, especially in the uncircumcised male. Secretion and different organisms retained under the foreskin produce irritation and infection, which are thought to predispose to cancer cellular changes. (45)
There is an epidemic outbreak of Kaposi's sarcoma in sexually active male homosexuals. (44-48) Kaposi's sarcoma is a cancer of the skin, mucous membranes, and Iymph nodes. Those affected have an acquired immunodeficiency syndrome (AIDS). In addition to Kaposi's sarcoma, male homosexuality is a risk factor for two other cancers: cancer of the anus (49) and cancer of the tongue.
Sexually active male homosexuals in good health can have a normal or abnormal immune system. Many with an abnormal immune system appear quite healthy. Some with a malfunctioning immune system have had Kaposi's sarcoma and/or fatal or life-threatening infections caused by Pneumocystis carinii. (50,51)
The immune impairment from AIDS seen in sexually active male homosexuals, intravenous drug users, prostitutes, and heterosexuals is now clearly related to infection by the HIV virus. Other risk factors leading to human susceptibility to HIV include amyl nitrite, a drug used as a sexual stimulant. Amyl nitrite produces a profound impairment of the immune system, especially the T Iymphocytes. (52) Also, immunological abnormalities are seen more often in homosexuals who have many sexual partners than in those who have only one partner.
Viral Risk Factors
Viruses have been shown to directly cause cancer in fish, birds, frog* and almost every mammal. Over one hundred viruses capable of causing cancer have been identified. Two human cancers, T cell leukemia and T cell Iymphoma, have been shown to be caused directly by viruses. Perhaps all the other white blood cell tumors will also be shown to be caused by viruses.
In the following chapters we will review nutritional risk factors, other risk factors that can lead to the development of cancer, and ways that the risk factors can be modified.
Where Do You Stand?
My Cancer Risk Factor Assessment test found on page 27 has been designed to assess your own risk factors based upon diet, weight, age, lifestyle, and other variables covered in this chapter. Take the test to evaluate your risk. We define risk for potentially developing cancer based upon the following letter combination totals:
A person in a high-risk category will not necessarily develop cancer. The high-risk category indicates only that a person in it is more at risk than a person in another category.
Following are a few examples of persons with various risk factors, their relative degrees of risk for developing cancer, and what they should do to modify those risks and thereby reduce their chance of developing cancer (and/or cardiovascular disease). After each risk factor the score is indicated in parentheses.
Consider Linda, a 56-year-old (C) New Jersey (B) housewife (O). She is 5 feet 5 inches tall, weighs 160 pounds (B), eats red meat daily, eats several eggs per week, drinks milk daily, consumes very little fiber-containing foods, and does not eat a balanced diet (A). She also smokes two packs of cigarettes a day, which has done for over fifteen years (A). Linda drinks socially (0) and has never had cancer (0), but her mother had breast cancer (B). She started having sexual intercourse at age 20 (0), first got pregnant at age 24 (0), has a history of fibrocystic breast disease (C), never had any radiation (0), and is relatively easygoing (0).
What is your risk of developing cancer? Take the following Cancer Risk Factor Assessment Test to determine your risk according to your diet, weight, age, lifestyle, and other factors discussed in this chapter. After you assess which factors pose a risk, you can begin to modify them according to my recommendations. Then take the test again to see if your overall risk has been reduced.
The test consists of a list of cancer risk factors, several statements associated with each risk factor, and a specified score associated with each statement. Choose the statement that most nearly applies to you and write its score in the blank. After going through the questionnaire, add up your scores. The zero scores won't count in the total.
Cancer Risk Factor Assessment Test
|If during 50% or more of your life two or more of the
following apply to you:
(1) one serving of red meat daily (including luncheon meat);
(2) 6 eggs per week;
(3) butter, milk, or cheese daily;
(4) little or no fiber foods (3 gm or less daily);
(5) frequent barbecued meats;
(6) below-average intake of vitamins and minerals.
|Score A __|
|If during 50% or more of your life two or more of the
following apply to you:
(1) red meat 4-5 times per week (including luncheon meat);
(2) 3-5 eggs per week;
(3) margarine, low-fat dairy products, some cheese
(4) 4-15 gm of fiber daily;
(5) average intake of vitamins and minerals.
|Score B __
|If during 50% or more of your life two or more of
the following apply to you:
(1 ) red meat and I egg once a week or none at all;
(2) poultry or fish daily or very frequently;
(3) margarine, skim milk, and skim milk products;
(4) 15-20 gm of fiber daily;
(5) above-average intake of vitamins and minerals.
|Score O __
|Ideal weight for men is 110 Ibs plus 5 Ibs per inch over
5 ft. For women, ideal weight is 100 Ibs plus 5 Ibs per
inch over 5 ft.|
|If you are 25 Ibs overweight. ||Score B __|
|If your are 10-24 Ibs over. ||Score C __|
|If you are less than 10 Ibs over. ||Score O __|
|Smoke 2 packs or more per day for 10 years or more. ||Score A __|
|Smoke 1-2 packs for 10 years or more, or quit smoking less than a year ago. ||Score A __|
|Smoke less than 1 pack for 10 years or more or smoke pipe or cigar. ||Score B __|
|Smoked 1-2 packs per day, a pipe, or a cigar but stopped 7-14 years ago. ||Score B __|
|Chew or snuff tobacco. ||Score B __|
|Inhaled others' smoke for 1 or more hours/day up to age 25. ||Score B __|
|Inhaled others' smoke for 1 or more hours/day from age 25 on. ||Score C __|
|Never smoked, quit smoking 15 years ago, or never inhaled others' smoke. ||Score 0 __|
|If you drink 4 oz or more of whiskey daily or equivalent alcohol content in other beverages. ||Score B __|
|If you drink 2-4 drinks per week. ||Score C __|
|If you drink 4 oz or more of whiskey daily or the equivalent alcohol content in other beverages and also:|
|Smoke less than I pack per day, or chew or snuff tobacco. ||Score B __|
|Smoke 1-2 packs per day, pipe, or cigar. ||Score A __ |
|Smoke 2 or more packs per day. ||Score A __|
|If you do not drink at all. ||Score 0 __|
|5. Radiation exposure|
|If you received multiple X rays or radiation treatments, or if you were exposed to radioactive isotopes used for diagnostic workups, or radioactive weapons. ||Score C __
|If you are fair-skinned and sunburn easily. ||Score B __|
|If neither applies. ||Score 0 __|
|If you are a radiologist, chemist, painter, uranium or hematite miner, luminous-dial painter, or a worker in the following industries: leather, foundry, printing, rubber, petroleum, furniture or cabinet, textile, nuclear, slaughterhouse, or plutonium. (The longer your exposure, the greater your risk.) ||Score B __|
|Never was one of the above workers. ||Score 0 __|
|If you have worked directly with one of the following chemicals: aniline, acrylonitrile, 4-aminobiphenyl, arsenic, asbestos, auramine manufacturing, benzene, benzidine, beryllium, cadmium, carbon tetrachloride, chlormethyl ether, chloroprene, chromate, isopropyl alcohol (acid process), nickel, mustard gas, or vinyl chloride. (The longer your exposure, the higher your risk.) ||Score A __|
|If you have worked indirectly with one of the above chemicals. ||Score C __|
|Never worked with one of the above. ||Score 0 __|
|8. Sexual-social history|
|If you are a female who started having sexual intercourse before age 16 and has had many male partners, particularly uncircumcised. ||Score C __|
|If you are a sexually active male homosexual who has had many male partners and/or uses amyl nitrite. ||Score C __|
|If neither applies. ||Score O __|
|9. Immunity, drugs, and hormones|
|If your physician said you have a severe deficiency in your immune system, or you have received an organ transplant. ||Score A __|
|If you've taken 1 or more of the following for a prolonged period of time: chlorambucil, cyclophosphamide, melphalan, or high-dose steroids (anticancer drugs). ||Score A __|
|If you have taken one or more of the following for a prolonged period of time: phenacetin, thiotepa, diethylstilbestrol (DES), birth control pills (conjugated estrogens), or 17 methyl-substituted androgens. ||Score B __|
|If you had early onset of menses or late onset of menopause, or never had menses at all. ||Score B __|
|If you were first pregnant late in life or never at all or had fibrocystic breast disease. ||Score C __|
|If none of the above apply. ||Score O __|
|Based on Figure 1.1 in Chapter 1, if during most of your life you lived in one of the states with the most cancer deaths. ||Score B __|
|If during most of your life you lived in a state that has a moderate number of cancer deaths. ||Score C __|
|If during most of your life you lived in a state with the least number of cancer deaths. ||Score O __|
|If your age is 70 or more. ||Score B __|
|If your age is 55 to 69. ||Score C __|
|If your age is 55 or under. ||Score O __|
|12. Personal history|
|If you had cancer. ||Score B __|
|If you never had cancer. ||Score O __|
|13. Family history|
|If one or more close-family members had cancer. ||Score B __|
|No family history of cancer. ||Score O __|
|If you exercise very little or not at all. ||Score C __|
|If you exercise 3 or more times a week and get your heart rate 50% higher than normal for at least 20 min. ||Score O __|
|If you are frustrated waiting in line, easily angered, and unable to control stress. ||Score C __|
|If you are comfortable when waiting, easygoing, and able to control stress. ||Score O __|
|TOTAL SCORE: _____A's; _____B's; and _____C's.|
|To evaluate your score, see "Where Do You Stand?"|
(Excerpted from Cancer and Nutrition: A Ten Point Plan to Reduce Your Risk of Getting Cancer ISBN: 0895294915)