THURSDAY, Aug. 23 (HealthDay News) -- There is a dose-response relationship between childhood radiation exposure of the pancreas and subsequent risk of diabetes, according to a study published online Aug. 23 in The Lancet Oncology.
Florent de Vathaire, Ph.D., from the Institut Gustave Roussy in Villejuif, France, and colleagues analyzed 2,520 questionnaire results and medical records from childhood cancer survivors treated between 1946 and 1985 in the United Kingdom and France to assess the correlation between radiation exposure and occurrence of diabetes. 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 was estimated for each child.
The researchers observed a strongly increased risk of diabetes with radiation dose to the tail of the pancreas, up to 20 to 29 Gy, which plateaued at higher doses. There was no significant effect noted for radiation dose to the other parts of the pancreas. At 1 Gy the estimated relative risk (RR) was 1.61. The RR was 11.5 for patients who received 10 Gy or more to the tail of the pancreas, compared with patients who did not receive radiotherapy. For the 511 patients who received more than 10 Gy to the tail of the pancreas, the cumulative incidence of diabetes was 16 percent. There was a significantly heightened sensitivity to radiation in children younger than 2 years at the time of radiotherapy, compared with older patients (RR at 1 Gy, 2.1 versus 1.4).
"The pancreas needs to be regarded as a critical organ when planning radiation therapy, particularly in children," the authors write.
One institution disclosed funding from Electricity de France for research in radiation epidemiology. The study was partially funded by the Pfizer Foundation for Child and Adolescent Health.