|Childhood cancer: risk of radiotherapies|
The cumulative incidence is the rate of cancer that occurred after treatment of a first cancer. The histogram shows the impacts in terms of past years for a cohort of 4500 children who had been treated for cancer by chemotherapy or radiotherapy between 1943 and 1985. Over 25 years, the incidence of a second cancer approaches 4% for radiotherapy and for chemotherapy. It is estimated that during the 30 years after treatment, children treated with radiotherapy are subject to a risk 5 to 10 times higher than children who did not undergo a first cancer.