Some children and young adults who undergo radiation therapy for cancer are at a greater risk of developing diabetes later in life, researchers from France and the UK have found.
Scientists assessed the relation between radiation exposure and occurrence of diabetes in a large cohort of long term childhood cancer survivors.
They sent a questionnaire to 3,468 survivors of a childhood cancer treated in eight centres in France and the UK between 1946 and 1985, of which 2,520 were returned. Each self-declaration of diabetes was confirmed by contacting the patients’ medical doctors.
‘We estimated the radiation dose received by the tail, head, and body of the pancreas and 185 other anatomical sites during each course of radiotherapy from 1990 to 1995 for each child after reconstruction of the conditions in which irradiation was delivered. We investigated the relation between the radiation dose to the pancreas and the risk of a subsequent diabetes diagnosis,’ said Florent de Vathaire from the Centre for Epidemiology and Public Health at the Gustave Roussy Institute in France.
Some 65 cases of diabetes were validated. The risk of diabetes increased strongly with radiation dose to the tail of the pancreas, the research found. The radiation dose to the other parts of the pancreas did not have a significant effect.
Our study provides evidence of a dose-response relation between radiation exposure of the pancreas and subsequent risk of diabetes. Because of the risks observed and the frequency of diabetes in the general population, this finding raises important public health issues,’ explained Vathaire.
‘The pancreas needs to be regarded as a critical organ when planning radiation therapy, particularly in children. Follow up of patients who received abdominal irradiation should include diabetes screening,’ she added.
By the age 45, some 6.6% of those who had received radiation were diagnosed with diabetes. That compared with 2.3% of those who hadn’t had radiation. The higher the dose, the more likely the children were to develop diabetes, the researchers reported in The Lancet medical journal.
About 366 million people had diabetes last year, according to estimates by the International Diabetes Federation. That number will probably increase to 552 million by 2030, caused by an aging population and lifestyle changes in poorer countries, according to the group.
Before the study, the effect of cancer treatment on the pancreas was largely unknown, and scientists now want to see further studies to clarify the mechanisms underlying diabetes after abdominal radiation.
