The Risk of Ischemic Stroke in Head and Neck Cancer Patients and Those Who Were Treated with Radiotherapy: A Population-Based Cohort Study

Abstract

Background: To investigate the standardized incidence ratios (SIR) of stroke in patients with head and neck cancer and their relationship to radiotherapy. Methods: Patients with head and neck cancer ages 20–85 years were enrolled from 2007 to 2016 using the Taiwan Cancer Registry. The study endpoint was fatal and non-fatal ischemic stroke, ascertained by the National Health Insurance Research Database. Age- and sex-adjusted SIRs, categorized by 10-year age standardization, were used to compare the patients with head and neck cancer with a randomly selected 2,000,000 general population. We compared the risk of stroke in patients with head and neck cancer who received radiotherapy or surgery alone. Multivariable adjusted hazard ratios (HR) and 95% confidence intervals (CI) were obtained from Cox regression analysis with competing risk. Results: Among 41,266 patients (mean age, 54.1 years; men, 90.6%) in the median follow-up period of 3.9 years, 1,407 strokes occurred. Compared with the general population, the overall SIR of stroke was 1.37 (95% CI, 1.30–1.44) in patients with head and neck cancer. In patients with head and neck cancer, the fully adjusted HR of stroke in those who received radiotherapy was 0.96 (95% CI, 0.83–1.10), compared with those who received surgery alone. Conclusions: Patients with head and neck cancer had a higher risk of fatal or non-fatal ischemic stroke. The risk of stroke was not higher in patients initially treated with radiotherapy. Impact: Oncologists should emphasize stroke prevention in all patients with head and neck cancer, not only in those who received radiotherapy.

Stroke Risk in Survivors of Head and Neck Cancer

“…Furthermore, nasopharyngeal carcinoma was excluded from their main analysis. We also note that the cohorts in the studies by Yeh et al and Kim et al predominately represented oral subsites (approximately 95% and 72%, respectively). In comparison, our cohort comprised of 48% nasopharyngeal, 18% oral cavity, and 13% laryngeal tumors.…”

“…A study by Kim et al reported an IRD of 5.88 strokes per 1000 PY with propensity-score matching. A study by Yeh et al used a method similar to ours and reported an SIRR of 1.37 for ischemic stroke. However, their study did not report on SIRD nor detail the stroke risks in different subpopulations within the HNC cohort.…”

“…Importantly, several studies have reported an increased risk of stroke in patients treated for HNC 4 , 5 , 6 , 7 , 8 , 9 , 10 (eTable 1 in Supplement 1 ). However, the precise estimation of stroke risk varied across these studies, primarily due to the difference in methods used.…”

“… 8 , 9 Moreover, different summary measures were used to quantify stroke risk in these studies. Some studies used incidence rate ratios, 4 , 5 , 7 , 10 while some used hazard ratios derived from Cox proportional hazards regression model. 6 , 8 , 9 , 11 Furthermore, most studies reported an increased risk in the overall HNC cohort, without providing detailed information about the risks in subpopulations.…”

Vertebral and Carotid Artery Stenosis after Irradiation Both Raise Ischemic Stroke Risk in Head and Neck Cancer Patients

“…4,5 Ischemic stroke (IS) is a common post-RT complication that occurs at a rate of 17.32 per 1,000 person-years, with an incidence rate ranging from 10% to 34% among HNC survivors after RT. [6][7][8][9][10] Studies have reported that compared with the general population, patients with HNC had a standardized stroke incidence ratio of 1.37 7 and had a relative risk of IS ranging from 2.09 over a 5-year follow-up period to 10.1 over a 7-year follow-up period after RT. 8,9 .…”