Stroke mortality in cancer survivors: A population-based study in Japan

Introduction: The association between cancer survivors and stroke deaths remains unclear. We aimed to evaluate the risk of fatal stroke in patients with cancer. Materials and methods: This study was conducted using data from the Osaka Cancer Registry and vital statistics in Japan, collected from 1985 to 2013. We extracted patient data and investigated the causes of death. Standardized mortality ratios were calculated to compare the risk of stroke in patients with cancer to that in the general population. Poisson regression models were used to estimate the risk of stroke in patients with cancer and other cancer subgroups. Stroke types were used for risk stratification. Results: We identified 688,473 eligible patients with cancer. The cohort contributed 2,668,126 person-years at risk. During the study period, 337,117 patients died; stroke was the cause of death in 5496 patients. Stroke types included cerebral infarction (3259), intracerebral hemorrhage (1539), subarachnoid hemorrhage (364), and other cerebrovascular diseases (334). The crude mortality rate from fatal stroke was 205.99 per 100,000 personyears. The standardized mortality ratio (95 % confidence interval) for fatal stroke was 1.75 (1.71-1.80). When stratified by stroke types, the ratios for cerebral infarction, intracerebral hemorrhage, and subarachnoid hemorrhage were 1.83 (1.76-1.89), 2.38 (2.26-2.50), and 2.28 (2.03-2.56), respectively. The risk of fatal stroke increased with time after cancer diagnosis. The multivariate Poisson regression model indicated that men were more likely to die of stroke than women. Conclusions: Cancer survivors have a higher risk of fatal stroke than the general population across all stroke types.