Who is at risk?

Who is at risk?

Anyone can develop cancer. The risk of being diagnosed with cancer increases as individuals grow older. Most cases occur in adults who are middle-aged or older. It is estimated that about 77% of all cancers are diagnosed in persons 55 and older.

The word risk is used in different ways by researchers, most commonly expressing risk as lifetime or relative.

Lifetime risk refers to the probability that an individual, over the course of a lifetime, will develop or die from cancer.  In the U.S., men have slightly less than a 1 in 2 lifetime risk for developing cancer. For women, the risk is a little more than 1 in 3.

Relative risk is a measure of the strength of the relationship between risk factors and a particular cancer.  It compares the risk of developing cancer in persons with a certain exposure or trait to the risk in persons who do not have this characteristic.  For example, women who have a first-degree relative (mother, sister, or daughter) with a history of breast cancer have about twice the risk of developing breast cancer compared with women who do not have a family history.

About 5% of all cancers are strongly hereditary, in that an inherited genetic alteration confers a very high risk of developing one or more specific types of cancer.  However, most cancers do not result from inherited genes but from damage (mutation) to genes that occurs during one’s lifetime.  Mutations may result from internal factors such as hormones or the digestion of nutrients within cells, or external factors such as tobacco, chemicals, and overexposure to sunlight (sunbathing at the hottest times of the day). Sun creams often contain carcinogens – yes really!