Dear Editor

Cancer patients exhibit an elevated stroke risk [1-5]. In a case-control study examining the epidemiology of cancer in stroke patients and their clinical course, we identified 72 active cancer and 72 control patients from the 1493 stroke admissions to Princess Margaret Hospital, Hong Kong in 2009. The prevalence of cancer among stroke patients was 4·8% (Table 1), and stroke was the first symptom of their cancer in nine patients. The proportions of ischemic stroke (IS) (79·2%) and haemorrhagic stroke (HS) (20·8%) in cancer group were comparable with noncancer group, and vascular risk factors (hypertension, diabetes mellitus, and hyperlipidemia) were less prevalent. The cancers we identified followed the local cancer epidemiology, with lung and colorectal cancer being the two most common types. In HS, both groups had similar proportions of deep parenchymal and lobar haemorrhages, but multiple haemorrhages were only seen in the three cancer patients. Except for the two acute promyelocytic leukaemia patients who bled, the distributions of other cancers among HS patients were similar to those with IS. Among IS, the proportions of patients in the four Oxfordshire-classified syndromes were comparable in the two groups. The etiology of IS was undetermined in half of the cancer patients compared with only 28·3% of the noncancer patients. There was no difference in the severity of neurological impairment [National Institutes of Health Stroke Scale (NIHSS) 10·7 (cancer) and 11·8 (noncancer)], but cancer patients had a higher hospital-acquired pneumonia (11·1% vs. 4·2%) and hospital mortality (31·9% vs. 12·5%) rates. At three-months poststroke, cancer remained the most important independent predictor of mortality [odds ratio 12·4 (3·0–51·4)], and more cancer patients were disabled. We concluded that stroke and cancer, when coinciding, carried a high morbidity and mortality rate. Often, the occurrence of stroke in cancer patients could not be sufficiently explained by conventional etiology, implicating the role of cancer-related factors in their stroke pathophysiology.

Table 1. Comparing the current study to the published cohorts on cancer in stroke
 Chaturvedi et al. (1994)[2]Zhang et al. (2007)[3]Oberndorfer et al. (2009)[4]Uemura et al. (2010)[5]Current study
  1. DM, diabetes mellitus; HS, haemorrhagic stroke; HT, hypertension; IS, ischemic stroke; TIA, transient ischemic attack.

No. of cancer patients33561535172
Stroke typeIS + TIAISIS + HSISIS + HS
Cancer definition for inclusion in the studyCurrent + new cancer diagnosed during stroke eventCurrent + new cancer diagnosed during stroke event, primary brain tumour was excludedCurrent + new cancer diagnosed during stroke event, primary brain tumour was excludedOnly new cancer diagnosed during stroke eventCurrent + new cancer diagnosed within two-months after stroke
Dominant cancer identified in the studyGynecological (20·6%)Prostate cancer (21·4%)

Urogenital cancer (27%)

Breast cancer (22%)

Gastrointestinal cancer (45%)

Lung cancer (26·4%)

Colorectal cancer (13·9%)

Conventional vascular risk factors in cancer patientsNot availableNo difference compared with noncancer patientsNo difference compared with noncancer patientsOlder age in cancer groupFewer HT, DM and hyperlipidemia in cancer group
Etiology (for IS)No comparison availableNo difference compared with noncancer patientsNo difference compared with noncancer patientsNo difference compared with noncancer patientsA higher proportion fell in undetermined etiology group
Prevalence of cancer in stroke3·5%3·9%12%3%4·8%


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  2. References
  • 1
    Nguyen T, DeAngelis LM. Stroke in cancer patients. Curr Neurol Neurosci Rep 2006; 6:187192.
  • 2
    Chaturvedi S, Ansell J, Recht L. Should cerebral ischemic events in cancer patients be considered a manifestation of hypercoagulability? Stroke 1994; 25:12151218.
  • 3
    Zhang YY, Cordato D, Shen Q, Sheng AZ, Hung WT, Chan DKY. Risk factor, pattern, etiology and outcome in ischaemic stroke patients with cancer: a nested case-control study. Cerebrovasc Dis 2007; 23:181187.
  • 4
    Oberndorfer S, Nussqruber V, Berger O, Lahrmann H, Grisold W. Stroke in cancer patients: a risk factor analysis. J Neurooncol 2009; 94:221226.
  • 5
    Uemura J, Kimura K, Sibazaki K, Inoue T, Iguchi Y, Yamashita S. Acute stroke patients have occult malignancy more often than expected. Eur Neurol 2010; 64:140144.