Doctors often cannot explain why one person develops cancer and another does not. But research shows that certain risk factors increase the chance that a person will develop cancer. These are the most common risk factors for cancer:
- Growing older
- Ionizing radiation
- Certain chemicals and other substance
- Some viruses and bacteria
- Certain hormones
- Family history of cancer
- Poor diet, lack of physical activity, or being overweight
Many of these risk factors can be avoided. Others, such as family history, cannot be avoided. People can help protect themselves by staying away from known risk factors whenever possible.
If you think you may be at risk for cancer, you should discuss this concern with your doctor. You may want to ask about reducing your risk and about a schedule for checkups.
Over time, several factors may act together to cause normal cells to become cancerous. When thinking about your risk of getting cancer, these are some things to keep in mind:
- Not everything causes cancer.
- Cancer is not caused by an injury, such as a bump or bruise.
- Cancer is not contagious. Although being infected with certain viruses or bacteria may increase the risk of some types of cancer, no one can "catch" cancer from another person.
- Having one or more risk factors does not mean that you will get cancer. Most people who have risk factors never develop cancer.
- Some people are more sensitive than others to the known risk factors.
- The most important risk factor for cancer is growing older. Most cancers occur in people over the age of 65. But people of all ages, including children, can get cancer, too.
Family History of Cancer
Most cancers develop because of changes (mutations) in genes. A normal cell may become a cancer cell after a series of gene changes occur. Tobacco use, certain viruses, or other factors in a person's lifestyle or environment can cause such changes in certain types of cells.
Some gene changes that increase the risk of cancer are passed from parent to child. These changes are present at birth in all cells of the body.
It is uncommon for cancer to run in a family. However, certain types of cancer do occur more often in some families than in the rest of the population. For example, melanoma and cancers of the breast, ovary, prostate, and colon sometimes run in families. Several cases of the same cancer type in a family may be linked to inherited gene changes, which may increase the chance of developing cancers. However, environmental factors may also be involved. Most of the time, multiple cases of cancer in a family are just a matter of chance.
If you think you may have a pattern of a certain type of cancer in your family, you may want to talk to your doctor. Your doctor may suggest ways to try to reduce your risk of cancer. Your doctor also may suggest exams that can detect cancer early.
You may want to ask your doctor about genetic testing. These tests can check for certain inherited gene changes that increase the chance of developing cancer. But inheriting a gene change does not mean that you will definitely develop cancer. It means that you have an increased chance of developing the disease.
Reference: National Cancer Institute (NCI)
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