Cancer: At a Glance
A cancer is an abnormal growth of cells (usually derived from a single abnormal cell). Cancer cells have lost normal control mechanisms and thus are able to grow and multiply continuously, invade adjacent tissues, and spread to distant parts of the body. Cancerous (malignant) cells can develop from any tissue in the body.
For a full discussion, see Overview of Cancer.
Many genetic and environmental factors can increase a person’s risk of cancer. But not all people who have risk factors develop cancer. So people should be alert for warning signs and follow the recommendations for cancer screening, such as those for colonoscopy, mammography, and skin cancer screening.
Cancer is much less common among children than among adults:
Some warning signs of cancer are general. That is, they are usually caused by something other than cancer and, when caused by cancer, do not help pinpoint any particular cancer. Still, their presence can help direct doctors to do the physical examinations and laboratory tests necessary to exclude or confirm a diagnosis.
Other warning signs are much more specific and steer doctors to a particular kind of cancer or location.
Some warning signs of possible cancer are
According to the American Cancer Society, the risk of developing certain cancers may be reduced by making lifestyle changes.
Measures known to reduce the risk of cancer:
Measures that may reduce the risk of cancer:
Limiting intake of high-fat foods, particularly from animal sources (for example, high-fat meats and whole-fat dairy products)
Limiting intake of processed meat
Increasing intake of fruits and vegetables
Increasing intake of whole-grain foods
Being physically active
Keeping weight below the obese level
How specific foods and supplements affect the risk of getting cancer are unclear, but there is good evidence that obesity increases the risk of a number of cancers.