What is Cancer?

You've heard of it of course but, "What, exactly, is cancer?" This section provides an introduction to what it is, how it starts, and how it spreads.

Cancer is the term we give to a large group of diseases that vary in type and location but have one thing in common: abnormal cells growing out of control. Under normal circumstances, the number and growth of all our cells is a highly controlled mechanism. But when the control signals in one of these cells goes wrong and its life cycle becomes disturbed, it divides and divides. It continues on multiplying uncontrollably and the result of this accumulation of abnormal cells is a mass of cells called a tumor, or lump.

This resulting tumor can be either benign or malignant. A benign tumor does not spread, or metastasize, to other parts of the body, is noncancerous, and is rarely life-threatening. Many breast lumps, for example, are benign tumors. A malignant tumor, however, can spread and is cancerous. When this tumor spreads, its malignant cells break off and travel through the blood lymph system to other places in the body to settle and multiply, or metastasize, resulting in a new tumor called a secondary tumor, or metastasis. If the cancer has spread, doctors usually say it has 'metastasized'. The name given to the cancer, however, is reflective of the origination of the cancer even if it has spread to other areas of the body. For example, even if prostate cancer has spread to the liver it's still called prostate cancer.

How does it all start?

What causes this uncontrollable multiplication of abnormal cells in the first place, as well as how fast it happens, differs from person to person. Cancer starts when one normal cell becomes cancerous. This happens when something disrupts its DNA, altering this instructional code that monitors the cell's life cycle. In other words, the instructions that tell the cell how to grow, divide, and die properly have been disrupted. One or more of a variety of factors could have done the disrupting, including diet, tobacco, sun, radiation, or certain chemicals. Certain factors, such as tobacco, have been proven through research studies to be associated with cancer and are thus called risk factors.

Cancer can develop slowly over several years while the person has no symptoms and has no idea they have any cells going awry, developing into a cancer. It may take 30 years for a tumor to become large enough to produce any symptoms or it may occur in young children.

Many people overcome the disease and many living with the disease live fulfilled lives for many years. If you have been diagnosed with cancer, you may be wanting to learn more about what treatments to expect. Treatments for different types of cancers may be different.

Top Ten Cancer Risks

Below are factors known to be associated with cancer. Often several factors interacting with one another is what leads to cancer. Even if someone has a genetic susceptibility to cancer they may or may not develop the disease. Cancer development depends on the presence or absence of certain environmental factors that promote or inhibit cancer.

1. Genetic predisposition

   Certain types of cancer, such as colon and breast cancer, often run in families. It is the predisposition to cancer, though, not the cancer itself, that is inherited. Other non-genetic (i.e., environmental) factors must be present for the cancer to develop. These factors can either promote or hinder cancer, thus allowing or not allowing the disease to develop. If there is cancer in your family, it does not necessarily mean you will get cancer because environmental factors play a role also. However, having a family history of cancer does mean you are at a higher risk. It is even more important, then, for you to take action to reduce your risk. The following sections tell you how.

2. Overexposure to estrogen (for women)

   If a woman's system is exposed to too much estrogen in her blood system it puts her at increased risk for some gynecological cancers (e.g., breast, uterine). This is because estrogen stimulates cell proliferation in these tissues. A woman's level of exposure to estrogen is determined by a variety of factors, such as age at menarche (when she had her first period), pregnancy and age at pregnancy, age at menopause, weight, physical activity, and diet. For example, a woman with an early age at menarche and late age at menopause would have had a higher exposure to estrogen than a woman with a later age at menarche and earlier age at menarche, assuming dietary and other factors were constant.

   You can lower your estrogen level, and thus reduce your risk, by having a baby before 35 years of age, doing regular aerobic exercise, minimizing alcohol, and eating a low-fat diet. You may want to consider avoiding foods that may have estrogenic residues in them such as dairy products. Eating soybean-based foods may protect you against estrogens that are found in common pesticides and industrial pollutants.

3. Ionizing radiation

   Overexposure to ionizing radiation, such as X rays and nuclear radiation, can cause DNA injury that may lead to cancer. Your risk of DNA damage from ionizing radation depends on how much of this type of radiation you have received over your lifetime so it's a good idea to reduce the number of X rays you receive by only getting them when absolutely necessary. Other ways to reduce your exposure to ionizing radiation are not living near a nuclear power plant or nuclear waste disposal site and making sure your home does not have dangerous levels of radon, a radioactive gas emitted from the earth in some geographic regions. Since the benefits of mammograms likely outweigh the risks, especially for women at high risk for getting breast cancer, obtaining mammograms should not be sacrificed just to avoid exposure to the radiation associated with the procedure.

4. Ultraviolet radiation

Ultraviolet radiation is the radiation from the sun that reaches the earth. The most harmful of this type of radiation are the high-frequency, DNA-damaging ultraviolet B rays. These are the rays that cause 90 percent of all skin cancers. Cover up with clothing and sunscreen with a high SPF. Be especially sure to cover up those areas that are most susceptible to skin cancers such as ears, cheeks, and nose.

5. Carcinogenic chemicals

Chemical carcinogens such as asbestos, benzene, formaldehyde, and diesel exhaust are dangerous in high concentrations. This level of concentration often used to exist in some workplaces. Strict control over the past 50 years of such occupational carcinogens, however, have greatly reduced cancers caused by these substances.

6. Tobacco smoke

Smoking causes 30 percent of all cancer deaths in the U.S. This makes tobacco smoke the single most lethal carcinogen in the U.S. Smoking causes more than just lung cancer; it also causes cancers of the upper respiratory tract, esophagus, bladder, and pancreas and may also cause cancer of the stomach, liver, kidney, colon, and rectum. Secondhand smoke also causes a few thousand deaths from lung cancer among nonsmokers. Lung cancer survival rate is low because lung cancer usually goes undetected until it is too late and has spread. The single most effective way to reduce lung cancer risk is to quit smoking if you are a smoker and to limit your exposure to secondhand smoke if you are a nonsmoker.

7. Alcohol

Alcohol is estimated to contribute to about 3 percent of deaths from cancer. Persons who drink alcohol heavily have a higher risk of mouth, throat, esophagus, stomach, and liver cancer. Although alcohol appears to reduce the risk of heart disease, other evidence also suggests that even one alcoholic drink a day is associated with breast and possibly colon and rectal cancer.

8. Carcinogenic foods

Certain carcinogenic foods should be limited while others should be eliminated altogether. Salted, pickled, and smoked foods such as pickles or smoked fish, and meats treated with nitrites should be limited. Salt appears to contribute significantly to cancer. Meats that have been charred over a grill should be eliminated from the diet because the charred part is carcinogenic. Taking the antioxidant vitamin C through vitamin C rich foods or supplementation may protect against the cancer-causing effects of carcinogenic foods. Hot drinks have also been shown to be associated with higher esophageal cancer risk.

9. Unhealthy diet

Animal (saturated) fat, and especially that from red meat, is associated with several different types of cancer, including the colon, rectum, and prostate. The effect of diet on cancer may have as much to do with foods that are in a diet as foods that are not in a diet. Adopting certain dietary habits, such as reducing dietary fat and eating more soy-based foods, fiber, fruites, and vegetables, can offer some protection against cancer because they contain certain properties, such as antioxidant activity, that act as cancer blockers.

10. Free radicals

Free radicals are dangerous, highly reactive chemical compounds that can damage DNA and lead to cancer. They are generated in various ways. For example, polyunsaturated fats tend to oxidize and thus form free radicals. A build up of free radicals in a person's system occurs when the body's own biochemical mechanisms for reducing their levels cannot keep up with their production and there becomes an abundance of free radicals in the system. In this case it is important that the body be supplemented with antioxidants to finish up the job. Antioxidants block oxidation and thus free radical formation. Vitamins C and A are excellent antioxidants and can be taken through supplemenation as well as a diet high in yellow and orange fruits and vegetables.