Young nasopharyngeal cancer patients with radiotherapy and chemotherapy are most prone to ischaemic risk of stroke: a national database, controlled cohort study.

OBJECTIVES: This population-based cohort study investigated the ischaemic stroke risk of patients with nasopharyngeal carcinoma (NPC) by treatment. DESIGN: Controlled cohort study. SETTING: Based on claims data of National Health Research Insurance Database in years 1996-2010. PARTICIPANTS: A total of 4615 patients with nasopharyngeal carcinoma newly diagnosed in 2000-2003 were divided into three subgroups: patients received radiotherapy only, patients received both radiotherapy/chemotherapy and patients received neither radiotherapy nor chemotherapy (non-radio/chemotherapy). They were compared with 36 919 reference persons without stroke and cancer, frequency matched with demographic characteristics. MAIN OUTCOME MEASURES: Study subjects were followed up until 2010 to measure ischaemic stroke incidences. Risks associated with treatment and comorbidity were evaluated using Cox proportional hazards regression analysis incorporated with the competing risk of deaths. RESULTS: Ischaemic stroke incidence rates were ≈2-fold higher in nasopharyngeal carcinoma patients with radiotherapy, radiotherapy/chemotherapy and non-radio/chemotherapy than in references (13.8, 12.8 and 12.6 versus 6.07 per 1000 person-years, respectively). The risk was much higher for 20- to 39-year-old nasopharyngeal carcinoma patients with radiotherapy/chemotherapy [hazard ratio (HR) 14.7, 95% confidence interval 9.24-23.4]. Hypertension, diabetes, hyperlipidaemia and alcoholism also enhanced the risk with hazard ratios ranging from 2.4 to 9.3. The overall adjusted ischaemic stroke risk was higher in nasopharyngeal carcinoma patients with the two types of treatment than those without, but not significant. CONCLUSIONS: Patients with nasopharyngeal carcinoma are at an elevated risk of ischaemic stroke, without significant difference among treatment modalities. The relative risk is more prominent in younger patients. Comorbidity may enhance the risk.

Increase in stroke risk in patients with head and neck cancer: a retrospective cohort study.

BACKGROUND: This study investigated the stroke risk in patients with head and neck cancers (HNCs) using population-based data. METHODS: From claims collected in the Taiwan National Health Insurance database, we identified 13,390 HNC patients with diagnosis made in 2000-2002. A reference cohort of 53,517 non-cancer individuals matched for age, gender, and stroke risk factors was used for assessing stroke risk in follow-up to 2008. RESULTS: The overall stroke incidence was 1.44-fold higher in the HNC than in the reference cohort (11.4 vs 7.9 per 1000 person-years). Adjusted hazard ratios (HRs) were 1.54 (95% confidence interval (CI): 1.40-1.68) for ischaemic stroke and 1.36 (95% CI: 1.09-1.69) for haemorrhagic stroke. The cancer-to-reference stroke incidence rate ratio was age dependent and the highest in the age group younger than 40 years (5.45, 95% CI: 3.78-7.87) and decreased with aging. Comparing different therapeutic modalities, HNC patients receiving both radiotherapy (RT) and chemotherapy (CT) had the highest stroke risk (HR: 1.46, 95% CI: 1.22-1.74), followed in sequence by those who had CT alone, RT alone, and without therapy. CONCLUSION: Patients with HNC are at increased risk of developing stroke, especially in the young age group and in those who received both RT and CT.