Cancer is a disease that happens when cells grow and divide very quickly and don’t die like they are supposed to. Cancer cells can also spread to other parts of the body and make you sick. The way that cancer develops depends on many things, such as your lifestyle, the genes you get from your parents and whether you are exposed to certain substances that can cause cancer. Most of the time, doctors don’t know what causes some types of cancer.
In some cases, cancer can be prevented. For example, avoiding too much sun can reduce your risk of skin cancer. Regular visits to your doctor for routine screenings can help you catch early signs and symptoms of cancer. If you do have symptoms, such as unexplained weight loss or a lump, talk to your doctor right away.
Some kinds of cancer can be prevented, but some are not. The most common cancers are lung, breast and colon cancer. These cancers are more likely to happen as you get older. Most of these cancers are not caused by something you do or don’t do, but they can be prevented or caught early with screening tests.
Most cancers start in the cells that line blood vessels and lymph (say: LYE-droh) tubes. Cells in these tissues usually stay healthy and don’t change. But sometimes the cells change and grow out of control. These mutated cells may stick together and form a tumor, or lump. Cancer can also start in other tissues, such as skin, muscle or bones. Cancer can spread to other parts of the body through the blood or lymph system. When this happens, the cancer is called metastasis.
Some cancers are more likely to grow and spread if they have certain changes in their genes. These genetic changes can be caused by many different things, such as being exposed to certain chemicals or smoking. They can also be inherited from your parents or arise from mistakes that occur when the DNA in cells is copied during cell division.
Cancer can also develop when the lining of a blood vessel or lymph tube becomes irritated and damaged. This can cause the cells that line the blood vessel or lymph to grow and form a tumor. The tumor can then break apart and spread to other areas of the body, where it continues growing and forms new tumors.
There are many different kinds of cancer, and each one is named for the organ or tissue where it starts. For example, breast cancer that spreads to the lungs is still considered to be breast cancer.
Scientists aren’t sure what causes some cancers, but they do know that some things can lower your risk for developing them. These include eating a balanced diet, staying physically active and not smoking. In addition, getting routine screenings, such as a colonoscopy or mammogram, can help you find cancer early when it is easier to treat. Also, protecting your skin from too much sun exposure and limiting how often you sunburn can protect against skin cancer.