Survivors of childhood cancer have a life expectancy up to 28% shorter than people in the general population and should be closely monitored for much longer than is usual, according to a new study reported in the April 6 issue of the Annals of Internal Medicine.

"These results suggest that recognition and treatment of illnesses associated with late effects in the first 35 years after therapy for childhood cancer will probably result in improved longevity," write the researchers, led by Jennifer M. Yeh, Ph.D., from the Harvard School of Public Health in Boston, Massachusetts.

Due to advances in treatment, five-year survival rates for childhood cancer have risen to approximately 80 percent. As the population of long-term survivors continues to grow, health care providers will need to understand the late effects of cancer and its treatments on survivor's long-term health.

Cumulative excess mortality was estimated using data from the Childhood Cancer Survivor Study. Researchers developed a computer model to estimate the cumulative effect of disease- and treatment-related mortality risk for persons aged 15 years who had survived at least 5 years after receiving treatment for childhood cancer. They included children who had been diagnosed with cancer at the age of 10 and who had been treated 20 to 40 years ago.

They found that survivors of childhood cancers face health risks that shorten their life span by about 10 years on average. The loss in life expectancy varied for different types of cancer. Survivors of kidney cancer died about 4 years earlier, whereas survivors of bone and brain cancer died about 18 years earlier than the general population. The researchers suggest that use of treatment agents with late toxicities used in previous decades could be to blame.

The model for this estimate considered 3 risk categories: that for the original cancer diagnosis; that for excess mortality from subsequent cancer and late effects (including cardiac, pulmonary, and external complications), and that related to age-specific mortality rates in the general population.

The analysis showed an average lifetime probability of 0.10 for late-recurrence mortality, of 0.15 for treatment-related death from subsequent cancer or from other complications, and of 0.05 for death from other causes.

Life expectancy for survivors was 50.6 years, which was 10.4 years shorter than for the general population. Reduced life expectancy varied by tumor type; it was 4.0 years for kidney cancer and 17.8 years for brain or bone cancer.

The authors note that "monitoring the health of current survivors and carefully evaluating therapies with known late toxicities in patients with newly diagnosed cancer are needed." But they note that one limitation of their data is that treatment approaches have changed enormously in the past 20 years: for example, radiation therapy now uses greatly reduced doses and volumes and different methods of delivery.

The authors of an accompanying editorial conclude that physicians should consider the complexity of past treatments and their long-term and late effects when caring for these patients. "The important role of prevention and health promotion in this patient population should not be underestimated. Caring for the whole patient is essential, including the psychological needs that arise with the burden of living with a chronic disease," they write.