Childhood Cancer Survivors at Risk of Premature Death
TUESDAY July 13, 2010 -- Childhood cancer casts a long shadow. Those who survive the original cancer are at high risk of dying prematurely decades afterward from new cancers, heart disease and stroke likely caused by the cancer treatment itself, British researchers report.
Although more children are surviving cancer, many have long-term risks of dying prematurely from other diseases. These excess deaths, the researchers say, may be related to late complications of treatment, such as the long-term effects of radiation and chemotherapy.
Equally troubling is that many older survivors are not being monitored for these problems, the researchers added.
Compared to the general population, excess deaths may result from new primary cancers and circulatory disease that surface up to 45 years after a childhood cancer diagnosis, said lead researcher Raoul C. Reulen of the Center for Childhood Cancer Survivor Studies at the University of Birmingham.
Reulen noted that while the risk of death from the effects of new cancers and cancer treatments increases with age, many of the most vulnerable survivors are not monitored for these life-threatening health problems.
"In terms of absolute risk, older survivors are most at risk of dying of a second primary cancer and circulatory disease, yet are less likely to be on active follow-up," he said. "This suggests that survivors should be able to access health care intervention programs even many years" after they pass the mark for five-year survival.
The report is published in the July 14 issue of the Journal of the American Medical Association.
For the study, Reulen's team collected data on 17,981 children who survived cancer. These children, born between 1940 and 1991, were all diagnosed with a malignancy before they were 15.
By the end of 2006, 3,049 of these individuals had died. That was a rate 11 times higher than would be seen in the general population -- something called the general mortality rate. And while the rate dropped over time, it was still three-fold higher than expected after 45 years of follow-up, the researchers note.
While the absolute risk of death from a recurrence of the original cancer dropped over time, the risk of dying from a different cancer, heart disease or stroke increased.
After the 45-year follow-up, the number of deaths among the childhood cancer survivors was 3.6 times higher for a second primary cancer than would be expected in the general population, and 26 percent of all excess deaths were caused by heart disease or stroke, Reulen's team found.
"Beyond 45 years from diagnosis, recurrence accounted for 7 percent of the excess number of deaths observed while second primary cancers and circulatory deaths together accounted for 77 percent," the researchers wrote.
The deaths from heart disease and stroke likely stem from late complications of treatment, the researchers added.
Dr. J. Leonard Lichtenfeld, deputy chief medical officer at the American Cancer Society, said that "long-term problems of childhood cancer survivors give us clues what the impact is of the treatment we offer."
"It is not unexpected that we see an increase in second cancers and increases in heart disease," he added.
However, Lichtenfeld concurs that a key problem is that many of these cancer survivors do not get regular follow-up and screening for cancer and other diseases as they get older.
"The children are well-followed when they are young adults, but as they get older, they tend to do what other people do. They overcome their disease and they are lost to follow-up," he said.
Lichtenfeld also noted that today treatments are less toxic and more targeted than they used to be. So these newer treatments may have fewer long-term adverse consequences.
"The side effect of our success [is] the side effects of the treatment themselves," he said. "Patients and physicians must be vigilant to know what the long-term effects of these treatments may be."
Posted: July 2010