NEW YORK (Reuters Health) – Patients younger than 60 years who undergo radiotherapy on the neck have an increased risk of ischemic stroke, according to a report in the January 1st issue of the Journal of Clinical Oncology.
Dr. Willem Boogerd and colleagues, from the Netherlands Cancer Institute, Amsterdam, examined the risk of ischemic stroke in patients irradiated for head and neck tumors before the age of 60 years. They determined the incidence of ischemic stroke in 162 patients with larynx carcinoma, 114 with pleomorphic adenomas, and 91 with parotid carcinoma, who had been treated with local radiotherapy.
After adjusting for sex and age, the researchers determined the relative risk (RR) of ischemic stroke using population rates from a stroke-incidence register. The median follow-up time after radiotherapy was 7.7 years.
Overall, 14 cases of stroke occurred (RR = 5.6), including 8 in patients with larynx carcinoma (RR = 5.1), 4 in those with pleomorphic adenoma (RR = 5.7), and 2 in those with parotid carcinoma (RR = 8.5).
"Five of six strokes in patients irradiated for a parotid tumor occurred at the ipsilateral side," the investigators note. "Analysis of other risk factors for cerebrovascular disease showed hypertension and diabetes mellitus to cause an increase of the RR after radiotherapy."
The RR after more than 10 years' follow-up was 10.1, Dr. Boogerd and colleagues explain. After 15 years, the cumulative risk of stroke after irradiation for head and neck tumors was 12.0%.