Increased risk of ischemic stroke in cervical cancer patients received radiotherapy: A nationwide population-based study
Chemotherapy, radiotherapy, and surgery have been reported to affect the incidence of ischemic stroke in cervical cancer. However, limited sample size and short-term follow up impair the power of analysis. This study aimed to evaluate the impact of different treatment modalities on risk of ischemic stroke (IS) with national population and long-term follow up. We conducted a nationwide population-based, retrospective cohort study using claims data from Taiwan's National Health Insurance program between 2008 and 2014. Cervical cancer patients aged 20 years or more who underwent surgery alone with oophorectomy (n = 1895) were compared with those who received surgery plus chemotherapy (SCT) (n = 1049), concurrent chemotherapy plus radiotherapy (CCRT) (n = 2631), chemotherapy (C/T) alone (n = 1778), and radiotherapy (RT) alone (n = 580). The follow-up period ranged from 5 to 11 years. The multivariate Cox proportional hazards regression models, Kaplan-Meier product-limit method, and the Gray k-sample test were used to assess the risk of IS. During a median follow-up period of 9.1 years, a total of 258 cases (3.3 %) developed IS with the shortest median time-to-event of 1 year in the RT group. The development of IS had negative impact on patients older than 55 years old (hazard ratio, 2.71; 95 % confidence level, 1.96-3.74). In comparison to surgery alone, the hazard risk of IS risk were 1.92, 1.58, and 3.26 for C/T, CCRT, and RT alone, respectively. When stratified by age older than 55 years, older patients who received RT alone had higher risk in terms of treatment modalities. For comorbidity sub-analysis, the older patients had higher risk of IS particularly in those bearing more than two stroke-related risk factors (6.3 % in <55 y/o versus 16.7 % in >55 y/o). For cervical cancer patients older than 55 years old and/or bearing comorbidities related to IS, the RT alone remains reasonable option and the risk of IS should be cautioned.