For an as yet unknown reason, cancer radiotherapy can increase the risk of cardiovascular disease later in life, a problem that is growing as more and more people survive their cancer diagnosis. New research from Karolinska Institutet now suggests that sustained inflammation induced by post-radiotherapy changes in the gene expression in the arteries could be the cause.
Epidemiological studies have shown that a course of radiotherapy increases the risk of cardiovascular disease in the same part of the body; for example, myocardial infarction after left-side breast cancer treatment, or stroke after the treatment of head and neck or brain tumours. Scientists know very little, however, about the biological causes of these serious side-effects, which often do not appear until many years following treatment.
"Studies have been hampered by the fact that the disease process is so slow," says Martin Halle, researcher at Karolinska Institutet. "Cell studies and animal studies are best suited to the more immediate effects, and studies on human subjects have been ruled out for ethical reasons."