Estudio: radioterapia ligada a la enfermedad crónica

por Brendon Nafziger, DOTmed News Associate Editor | September 16, 2010
High doses of radiotherapy delivered to the abdomen ups risk for diabetes, according to a study reaffirming the results of a 2009 analysis of childhood cancer survivors.

Using data gathered over several decades from hundreds of patients treated with radiation for peptic ulcers, the researchers found a nearly four-fold higher risk of dying from diabetes for patients with the highest estimated exposure to the pancreas.

The findings appeared in Archives of Internal Medicine this week.

"The association of [diabetes mellitus] following total body irradiation in children and adults has been documented, but less well known is the occurrence of DM following abdominal, or more specifically, pancreatic irradiation," wrote the researchers, led by Ruth A. Kleinerman and Dr. Kiyohiko Mabuchi, both with the radiation epidemiology branch of the National Cancer Institute.

The current study used data from an analysis of cancer risk from radiation treatment to the abdomen at the University of Chicago between 1937 and 1965. Numbers were small, with around 19 of the 1,832 radiated patients dying from diabetes as the underlying cause, compared with 11 of the 1,868 non-irradiated patients. Findings were only significant for patients getting the highest doses to the pancreas, and who lived for 15 years or more after treatment. These doses, estimated by reviewing records and from phantom experiments, were around 17-38 Gy, 170,000 to 380,000 times the strength of a chest X-ray.

In a 2009 study led by Dr. Lillian R. Meacham of Emory University, and also appearing in Archives of Internal Medicine, researchers found children who received radiation treatments for cancer had a seven-fold increase in risk for diabetes from whole-body radiation and a nearly three-fold increased risk from abdominal radiation.

Other smaller studies have also pointed to a link between abdominal radiotherapy and diabetes. A small French case study from the early 1990s found that diabetes occurred within two decades of abdominal radiation for Hodgkin's lymphoma or testis cancer in four of five adults.

"In conclusion, our data provide additional evidence of the association between DM and high-dose pancreatic radiation," the researchers said, "but leave some questions unresolved, [for example] the extent of pancreatic cell damage involved and the risk of DM at lower doses, both of which are important for both clinical practice and public health."