Basic Cancer Facts

Who Is at Risk of Developing Cancer?

  

Cancer most commonly develops in older people; 78% of all cancer diagnoses are in people 55 years of age or older. People who smoke, eat an unhealthy diet, or are physically inactive also have a higher risk of cancer. Cancer researchers use the word “risk” in different ways, most commonly expressing risk as lifetime risk or relative risk. Lifetime risk refers to the probability that an individual will develop or die from cancer over the course of a lifetime. In the US, the lifetime risk of developing cancer is higher in men (slightly less than 1 in 2) than for women (a little more than 1 in 3). These probabilities are estimated based on the overall experience of the general population and may overestimate or underestimate individual risk because of differences in exposures (e.g., smoking), family history, and/or genetic susceptibility. Relative risk is a measure of the strength of the relationship between a risk factor and cancer. It compares the risk of developing cancer in people with a certain exposure or trait to the risk in people who do not have this characteristic. For example, men and women who smoke are about 25 times more likely to develop lung cancer than nonsmokers, so their relative risk is 25. Most relative risks are not this large. For example, women who have one first-degree relative (mother, sister, or daughter) with a history of breast cancer are about twice as likely to develop breast cancer as women who do not have this family history; in other words, their relative risk is about 2. For most types of cancer, risk is higher with a family history of the disease. It is now thought that many familial cancers arise not exclusively from genetic makeup, but from the interplay between common gene variations and lifestyle and environmental risk factors. Only a small proportion of cancers are strongly hereditary, in that an inherited genetic alteration confers a very high risk.

How Many People Alive Today Have Ever Had Cancer?

 Nearly 14.5 million Americans with a history of cancer were alive on January 1, 2014. Some of these individuals were diagnosed recently and are actively undergoing treatment, while others were diagnosed many years ago with no current evidence of cancer. 

 How Many New Cases Are Expected to Occur This Year? 

 About 1,658,370 new cancer cases are expected to be diagnosed in 2015. This estimate does not include carcinoma in situ (noninvasive cancer) of any site except urinary bladder, nor does it include basal cell or squamous cell skin cancers, which are not required to be reported to cancer registries.

 
How Many People Are Expected to Die of Cancer This Year?

 In 2026, about 589,430 Americans are expected to die of cancer, or about 1,620 people per day. Cancer is the second most common cause of death in the US, exceeded only by heart disease, and accounts for nearly 1 of every 4 deaths