Children with cancer now have higher survival rates but may face higher risks for heart disease, stroke and kidney failure in adulthood, say researchers who compared cancer survivors with their siblings.

Survival rates for children with cancer now approach 80 per cent, a major  improvement from when treatments were introduced in 1970.

But when Kevin Oeffinger and his colleagues at the Memorial Sloan-Kettering Cancer Center in New York looked at the outcomes of more than 10,000 adult survivors and about 3,000 of their siblings, they found survivors were more than three times as likely to have chronic health problems.

Cancer survivors were also eight times as likely as their siblings to have severe or life-threatening chronic health conditions, the researchers report in Thursday's issue of the New England Journal of Medicine.

Survivors must be monitored closely: expert

"These findings imply that vigorous and long-term monitoring of young cancer survivors, accompanied by early intervention when problems arise, is mandatory," concluded Philip Rosoff of the Duke University School of Medicine, in a journal commentary accompanying the study. 

"There is a dark side to being cured of cancer as a young person."

The survivors were first diagnosed with cancer between 1970 and 1986. They were vulnerable to second cancers, heart conditions, kidney disease, severe
musculoskeletal problems and endocrine abnormalities such as thyroid disease, osteoporosis and sterility.

The risks were highest among survivors of bone tumours, nerve and brain cancer, and Hodgkin's disease, the study suggests.

The risks were also cumulative, with no evidence of a plateau so far, the researchers said.

Future survivors may be vulnerable to other risks

Since cancer treatments have evolved since those in the first study, future survivors may face other long-term complications, Rosoff said.

Oeffinger, a family physician, has suggested more doctors learn about the late effects of cancer care, since childhood cancer survivors drift away from the care of pediatric oncologists.

More training needed for doctors

The training could be added to residency programs, or postgraduate training fellowships in adult susceptibility could be developed, Rosoff said.

Patients themselves could carry a document describing their treatment, its potential late complications and types of behaviour that could reduce their risks of late effects, he added. 

Some cancer advocacy groups recommend patients of all ages track their drug and radiation doses.