Childhood cancer survivors at risk for stroke

NEW YORK (Reuters Health) - Survivors of childhood leukemia and brain tumors have an increased risk of stroke later in life, a study shows. This is particularly true for children treated with radiation therapy to the head at doses greater than 30 Gy.

These findings justify the continuation of efforts to reduce radiation doses in children being treated for leukemia or brain tumors when possible, conclude Dr. Daniel C. Bowers from The University of Texas Southwestern Medical School, Dallas, and colleagues.

The study, which was published in the Journal of Clinical Oncology, included 4,828 leukemia survivors and 1,871 brain tumor survivors. These subjects, who were younger than 21 years when they were diagnosed between 1970 and 1986, were compared with a group of 3,846 of their siblings.

This is the first study, the authors point out, to look at the risk of late-occurring stroke among childhood leukemia survivors and is "by far the largest study" to examine the risk of stroke in childhood brain tumor survivors.

According to the team, 37 leukemia survivors and 63 brain tumor survivors experienced a stroke 5 or more years after diagnosis.

Compared with the sibling group, the leukemia survivors had 6.4-fold greater risk of stroke, and the risk for brain tumor survivors was increased by 29.0-fold.

In children who received radiotherapy at an average dose of 30 Gy or greater had a stroke risk that increased in a dose-dependent fashion.

"Importantly, although the risk of stroke among leukemia and brain tumor survivors is significantly increased, it is still a relatively uncommon event during the first two decades after the cancer diagnosis," the authors note.

The rate of late-occurring stroke for leukemia survivors was 57.9 per 100,000 per year, and 267.6 per 100,000 per year for brain tumor survivors.

"How this risk will change as these cancer survivors age is not known," the study team points out.

SOURCE: Journal of Clinical Oncology, November 20, 2006.