Radiotherapy Is Associated with an Accelerated Risk of Ischemic Stroke in Oral Cavity Cancer Survivors after Primary Surgery

Abstract

The number of oral cavity carcinoma (OCC) survivors continues to increase due to advances in definitive surgery and radiation therapy (RT), however the risk of ischemic stroke is unclear in long-term survivors. In this study, survivors are defined as those who survived for >5 years after a diagnosis of OCC. They were matched at a 1:5 ratio with normal controls. Those who received surgery alone versus surgery+RT were also matched at a 1:1 ratio. From 2000 to 2005, 5172 OCC survivors who received surgery alone (n = 3205) or surgery+RT (n = 1967), and 25,860 matched normal controls were analyzed using stratified Cox regression models. Adjusted HRs (aHR) revealed that the surgery+RT group (aHR = 1.68, p < 0.001) had an elevated risk of stroke, but this was not seen in the surgery alone group (aHR = 0.99, p = 0.953). Furthermore, the age at stroke onset was at least 10 years earlier in the surgery+RT group than in the controls. In conclusion, radiotherapy increased the risk of ischemic stroke by 68% and also accelerated the onset of stroke in long-term OCC survivors after primary surgery compared with matched normal controls. Secondary prevention should include stroke as a late complication in OCC survivorship programs.