Treatments for cancer administered during childhood can have a negative effect on the heart for up to 30 years after beating the disease, research has found.
While having life-saving effects on cancer sufferers, chemotherapy and radiotherapy can have a toxic effect on the heart in later life.
The effects may actually be more serious than previously thought, with a new study revealing that damage can be caused by even a small amount of the cancer drugs being administered.
In the largest analysis of heart disease in childhood cancer survivors, researchers followed 14,000 people over a 30-year period after they were treated for cancer.
The average age at which the people in the study were diagnosed with cancer was six, with 40% of those being under five when they developed the disease.
They were given different combinations of treatments from chemotherapy, radiotherapy and surgery. Most received both chemotherapy and radiotherapy, with only 0.3% being given radiotherapy alone.
In the 30 years after their treatment, the cancer survivors were found to be five or six times more likely to develop problems, like heart failure, than their brothers and sisters.
This remained true when other factors which could negatively affect the heart, such as smoking, were considered.
The authors of the research, from the University of Minnesota Medical School, said: "The incidence of each cardiovascular outcome increased with time from diagnosis, which suggests that the long term impact of treatment on the health of cancer survivors will be substantial."