Two-thirds of them have survived cancer for at least five years, says researcher Yi Ning, MD, ScD, of the Virginia Commonwealth University Massey Cancer Center in Richmond.
As a result, "it is increasingly important to understand major causes of death among cancer survivors to improve the quality of life and prolong their life," he tells WebMD.
So Ning and colleagues examined data on 1,807 cancer survivors who participated in the 1988-1994 and 1999-2004 National Health and Nutrition Examination Surveys (NHANES).
The cancer survivors were followed for an average of about seven years, during which time 776 of them died.
Fifty-one percent died from cancer and 49% died from other causes.
Heart Disease Leading Killer
So what did they die from? Not surprisingly, heart disease -- the No. 1 killer in the U.S. -- was responsible for over two-thirds of the noncancer deaths.
The findings were presented here at the annual meeting of the American Association for Cancer Research.
The study also showed that that the longer people lived after their initial cancer diagnosis, the more likely they were to die from another disease. In the first five years of diagnosis, 33% of survivors died from a condition other than cancer compared with 63% after 20 years.
Also, people diagnosed with cancer at older ages were more likely to die from diseases other than cancer, Ning says.
Finding the Good in the Bad
"The good news is that people who are cured of their cancer are really cured," says Louis M. Weiner, MD, director of the Georgetown Lombardi Comprehensive Cancer Center in Washington, D.C.
"The challenge is that people who have been through the crucible of cancer treatment and come out intact must pay more attention to other aspects of their health," he tells WebMD.
Ironically, that means taking many of the steps recommended to prevent cancer in the first place: Not smoking, getting regular physical activity, eating healthy foods, and limiting alcohol use, for example.
Weiner suggests cancer survivors take advantage of the many cancer survivorship networks available across the country.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.