Patients with nasopharyngeal cancer (NPC) are at an increased risk for ischemic stroke, particularly if comorbidities are present, report researchers.
Furthermore, the risk is more prominent in younger individuals, write Shang-Wen Chen (China Medical University Hospital, Taichung, Taiwan) and colleagues in Clinical Otolaryngology.
Administration of radiotherapy or combination radiotherapy/chemotherapy to NPC patients may increase the risk for carotid stenosis because carotid arteries are always included in the irradiated field, explains the team. Yet, studies investigating stroke risk among large populations of such patients are limited.
Using inpatient and ambulatory cancer care records and claims data from a Taiwanese National Health Insurance Program, the team identified 4615 individuals with NPC newly diagnosed in 2000-2003 and with follow-up data available until the end of 2010.
The patients, who were divided into three groups according to whether they had received radiotherapy only, a combination of radiotherapy and chemotherapy, or neither (because they opted for complementary alternative medicine), were compared with 36,919 individuals without a history of cancer or stroke who were matched for age, gender, and the year the NPC patient was identified.
Overall, ischemic stroke rates were a significant two-fold higher among NPC patients than controls, at 13.8, 12.8, and 13.2 per 1000 person-years for patients who received radiotherapy, combination therapy, or neither therapy, respectively, versus 6.06 per 1000 person-years among controls. The differences among the NPC groups were not significant.
However, a significant association was observed between increasing stroke rates and decreasing age across all three treatment groups, compared with the reference cohort.
And among individuals aged 20-39 years, the stroke risk was significantly higher in the combination therapy group than in those who received radiotherapy or neither therapy, at hazard ratios of 14.7 versus 9.23 and 6.67, respectively.
Furthermore, stroke incidence was significantly more frequent across all four groups when comorbidity was present, particularly if the comorbidity was hypertension, diabetes, hyperlipidemia, or alcoholism. In addition, patients with atrial fibrillation receiving radiotherapy care were at a significantly increased risk for stroke.
"The present study showed that the relative risk is increased in those with comorbidity and young patients as well," say the researchers, who suggest that NPC patients of all ages with comorbidity need to take medical counsel.
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