Cancer how does it occur

This can make someone very sick. Sometimes cancer cells break away from the original tumor and travel to other areas of the body, where they keep growing and can go on to form new tumors. This is how cancer spreads. The spread of a tumor to a new place in the body is called metastasis say: meh-TASS-tuh-sis. You probably know a kid who had chickenpox — maybe even you. But you probably don't know any kids who've had cancer.

If you packed a large football stadium with kids, probably only one child in that stadium would have cancer. Doctors aren't sure why some people get cancer and others don't. They do know that cancer is not contagious. You can't catch it from someone else who has it — cancer isn't caused by germs, like colds or the flu are.

So don't be afraid of other kids — or anyone else — with cancer. You can talk to, play with, and hug someone with cancer. Kids can't get cancer from anything they do either. Some kids think that a bump on the head causes brain cancer or that bad people get cancer.

This isn't true! Kids don't do anything wrong to get cancer. But some unhealthy habits, especially cigarette smoking or drinking too much alcohol every day, can make you a lot more likely to get cancer when you become an adult.

It can take a while for a doctor to figure out a kid has cancer. That's because the symptoms cancer can cause — weight loss, fevers, swollen glands, or feeling overly tired or sick for a while — usually are not caused by cancer.

When a kid has these problems, it's often caused by something less serious, like an infection. With medical testing, the doctor can figure out what's causing the trouble. If the doctor suspects cancer, he or she can do tests to figure out if that's the problem. A doctor might order X-rays and blood tests and recommend the person go to see an oncologist say: on-KAH-luh-jist.

An oncologist is a doctor who takes care of and treats cancer patients. The oncologist will likely run other tests to find out if someone really has cancer. If so, tests can determine what kind of cancer it is and if it has spread to other parts of the body. Based on the results, the doctor will decide the best way to treat it. One test that an oncologist or a surgeon may perform is a biopsy say: BY-op-see. Or by things coming from outside the body, such as the chemicals in tobacco smoke.

And some people can inherit faults in particular genes that make them more likely to develop a cancer. Some genes get damaged every day and cells are very good at repairing them.

But over time, the damage may build up. And once cells start growing too fast, they are more likely to pick up further mutations and less likely to be able to repair the damaged genes. Skip to main content. How cancer starts. This page tells you about how cancer starts. There is information about Cell changes and cancer. Manage your cookie settings here.

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Thank you! We've recently made some changes to the site, tell us what you think. Ask about which cancer screening tests and procedures are appropriate for you. Cancer is caused by changes mutations to the DNA within cells. The DNA inside a cell is packaged into a large number of individual genes, each of which contains a set of instructions telling the cell what functions to perform, as well as how to grow and divide. Errors in the instructions can cause the cell to stop its normal function and may allow a cell to become cancerous.

These mutations are the most common ones found in cancer. But many other gene mutations can contribute to causing cancer. Gene mutations occur frequently during normal cell growth. However, cells contain a mechanism that recognizes when a mistake occurs and repairs the mistake. Occasionally, a mistake is missed.

This could cause a cell to become cancerous. The gene mutations you're born with and those that you acquire throughout your life work together to cause cancer. For instance, if you've inherited a genetic mutation that predisposes you to cancer, that doesn't mean you're certain to get cancer. Instead, you may need one or more other gene mutations to cause cancer. Your inherited gene mutation could make you more likely than other people to develop cancer when exposed to a certain cancer-causing substance.

It's not clear just how many mutations must accumulate for cancer to form. It's likely that this varies among cancer types. While doctors have an idea of what may increase your risk of cancer, the majority of cancers occur in people who don't have any known risk factors.

Factors known to increase your risk of cancer include:. Cancer can take decades to develop. That's why most people diagnosed with cancer are 65 or older. While it's more common in older adults, cancer isn't exclusively an adult disease — cancer can be diagnosed at any age.

Certain lifestyle choices are known to increase your risk of cancer. Smoking, drinking more than one drink a day for women and up to two drinks a day for men, excessive exposure to the sun or frequent blistering sunburns, being obese, and having unsafe sex can contribute to cancer. You can change these habits to lower your risk of cancer — though some habits are easier to change than others. Only a small portion of cancers are due to an inherited condition.

If cancer is common in your family, it's possible that mutations are being passed from one generation to the next. You might be a candidate for genetic testing to see whether you have inherited mutations that might increase your risk of certain cancers. Keep in mind that having an inherited genetic mutation doesn't necessarily mean you'll get cancer.

Some chronic health conditions, such as ulcerative colitis, can markedly increase your risk of developing certain cancers. Talk to your doctor about your risk. The environment around you may contain harmful chemicals that can increase your risk of cancer.