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What Is Cancer?
Cancer is the general name for a group of more than 100 diseases. Although there are many kinds of cancer, all cancers start because abnormal cells grow out of control. Untreated cancers can cause serious illness and death.Normal cells in the body
The body is made up of trillions of living cells. Normal body cells grow, divide, and die in an orderly fashion. During the early years of a person’s life, normal cells divide faster to allow the person to grow. After the person becomes an adult, most cells divide only to replace worn-out or dying cells or to repair injuries.How cancer starts
Cancer starts when cells in a part of the body start to grow out of control. Cancer cell growth is different from normal cell growth. Instead of dying, cancer cells continue to grow and form new, abnormal cells. Cancer cells can also invade (grow into) other tissues, something that normal cells cannot do. Growing out of control and invading other tissues are what makes a cell a cancer cell.Cells become cancer cells because of DNA (deoxyribonucleic acid) damage. DNA is in every cell and it directs all the cell’s actions. In a normal cell, when DNA gets damaged the cell either repairs the damage or the cell dies. In cancer cells, the damaged DNA is not repaired, and the cell doesn’t die like it should. Instead, the cell goes on making new cells that the body doesn’t need. These new cells all have the same abnormal DNA as the first cell does.
People can inherit abnormal DNA, but most DNA damage is caused by mistakes that happen while the normal cell is reproducing or by something in the environment. Sometimes the cause of the DNA damage may be something obvious like cigarette smoking or sun exposure. But it’s rare to know exactly what caused any one person’s cancer.
In most cases, the cancer cells form a tumor. Some cancers, like leukemia, rarely form tumors. Instead, these cancer cells involve the blood and blood-forming organs and circulate through other tissues where they grow.
How cancer spreads
Cancer cells often travel to other parts of the body where they begin to grow and form new tumors. This happens when the cancer cells get into the body’s bloodstream or lymph vessels. Over time, the tumors replace normal tissue. The process of cancer spreading is called metastasis.How cancers differ
No matter where a cancer may spread, it’s always named for the place where it started. For example, breast cancer that has spread to the liver is called metastatic breast cancer, not liver cancer. Likewise, prostate cancer that has spread to the bone is called metastatic prostate cancer, not bone cancer.Different types of cancer can behave very differently. For instance, lung cancer and skin cancer are very different diseases. They grow at different rates and respond to different treatments. This is why people with cancer need treatment that is aimed at their kind of cancer.
Tumors that are not cancer
Not all tumors are cancer. Tumors that aren’t cancer are called benign. Benign tumors can cause problems – they can grow very large and press on healthy organs and tissues. But they cannot grow into (invade) other tissues. Because they can’t invade, they also can’t spread to other parts of the body (metastasize). These tumors are almost never life threatening.How common is cancer?
Half of all men and one-third of all women in the US will develop cancer during their lifetimes.Today, millions of people are living with cancer or have had cancer. The risk of developing many types of cancer can be reduced by changes in a person’s lifestyle, for example, by staying away from tobacco, limiting time in the sun, being physically active, and healthy eating.
There are also screening tests that can be done for some types of cancers so they can be found as early as possible – while they are small and before they have spread. In general, the earlier a cancer is found and treated, the better the chances are for living for many years.
No matter who you are, we can help. Contact us any time, day or night, for information and support. Call us at 1-800-227-2345 or visit www.cancer.org.
Lymph Nodes and CancerOur bodies have a network of lymph (limf) vessels and lymph nodes. This network collects fluid, debris, and other things that are in the body’s tissue, outside the bloodstream. Cancer can appear in the lymph nodes in two ways: it either starts there or spreads there from somewhere else.Questions People Ask About CancerGet answers to some of the most common questions people have about cancer.Is Cancer Contagious?Can you "catch" cancer from someone who has it through things like sex, kissing, touching, sharing meals, or breathing the same air? Find out here.Lifetime Probability of Developing or Dying From CancerSome cancers are more common than others. Here you can learn more about a person's chances of being diagnosed or dying from certain types of cancer over his or her lifetime.Cancer PrevalenceCancer prevalence is the number of people living with cancer at any point in time. It includes people diagnosed with cancer in the past as well as people recently diagnosed. Learn about the prevalence of different types of cancer here.Cancer Surveillance Programs and Registries in the United StatesCancer data can be used to look for trends over time, to find cancer patterns in certain groups of people, and to show whether screening and other prevention measures are making a difference. This information is a key part of cancer prevention and control efforts.Economic Impact of CancerGet a quick overview of the financial costs of cancer for society as a whole.History of CancerHere we provide an overview of how people have understood and described cancer throughout history, as well as how the treatment of cancer has evolved.Cancer Information on the InternetFor many people, the Internet has become the first place to go when looking for information. Here we will offer some basic information about the Internet, along with ideas on what to look for and what to avoid as you look for the facts you need.Other Sources of Cancer informationHere you can find additional organizations and websites that offer cancer information. These sources should be used for informational purposes only. If you have a health-related problem, please consult a doctor.Cancer VideosTo learn more about cancer and its treatment, watch these videos developed and reviewed by the health experts at Healthology. |
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