Stroke is the 2nd leading cause of death in the world. The Unites States has made some improvement, as announced this year at the ISC by dropping to 5th from 4th, but stroke remains a leading cause of mortality. Cancer occupies the #2 slot in the Unites States and represents another formidable illness. Besides making the infamous “top 5”, how do these two disease processes relate? When facing the patient with a diagnosed malignancy, how common is the occurrence of a stroke in the following years? Selvik et al. in the Norwegian NORSTROKE study found 15% of the patients enrolled in their large patient registry had a diagnosis of cancer prior to their ischemic stroke with the most common mechanism cardioembolic and a mean age of 76. While the risk of both cancer and stroke increase with age, what is the relationship between cancer and ischemic stroke among young adults? 

Aarnio et al. conduct a thought provoking study through their evaluation of the frequency of cancer and its association with long-term risk of death among young patients (15-49) with first-ever ischemic stroke. The author points out that the prevalence of cancer has been previously cited to be higher among young stroke patients compared to the general population.

1008 patients with first ever ischemic stroke (defined using clinical and imaging criteria) from a 13yr period were identified from a Finland hospital discharge database. Cancer diagnoses were extracted using ICD-9 codes as well as discharge diagnoses and verified. The authors only considered tumors with invasive features as cancer and excluded basal cell carcinoma and in situ lesions. Cancers diagnosed before stroke or during hospitalization for stroke were classified as pre-stroke cancers and those diagnosed after discharge as post-stroke.

77 (7.7%) of the patients had cancer diagnosed at any time with 36 before stroke onset, 3 during stroke hospitalization and 38 after discharge. Median time from pre-stroke cancer to ischemic stroke was 4.9 years and 6.7 years from stroke to post-stroke cancer diagnosis. Lung and respiratory tract cancer was the most common etiology. Interestingly, there were no cancers diagnosed in patients less than 30yo. The cumulative risk of death was significantly higher among the patients diagnosed with cancer regardless of the time of diagnoses in relationship to the occurrence of stroke (19.7% vs. 68.6%). Active cancer without any other apparent cause for stroke was the strongest factor associated with death compared to those without cancer.

How does this knowledge change our management as vascular neurologists? Is there a particular stroke mechanism we should look for in this patient population? 17/38 patients diagnosed with cancer after discharge had an “undetermined” stroke etiology. Should we be screening all young patients with a cryptogenic etiology for malignancy? A study published in Stroke in 2008 (mean age 52) found first-ever stroke as an initial presentation of systemic cancer in 0.4% suggesting it is a rare event. Should we nevertheless be prompted to act considering the unfavorable survival among this cohort of young stroke patients? While a systemic cancer workup is costly and should not be routinely performed, this study suggests that it could be considered in young patients in whom a stroke etiology is unclear.