Frequency and predictors of cancer in people with a history of stroke

Stroke is a frequent complication of cancer, as the latter may predispose to clot formation in the brain. A proportion of cancer-associated strokes occur during the silent phase of a cancer, before any symptoms may prompt its diagnosis. The early diagnosis of cancer after stroke is essential to improve prognosis. This poses a challenge, since the type and extent of cancer investigations that should be offered after a stroke remain uncertain. Moreover, knowledge on the risk of cancer after stroke in Canada is limited. This study intends to measure the frequency of cancer among people with a history of stroke, as compared to people without a history of stroke. This study also will identify predictors of cancer in people with stroke. Our goal is to shed further light on cancer-associated strokes that may help decision-makers and clinicians improve stroke and cancer care.

We used data on self-reported diagnoses of stroke and cancer from participants in the Comprehensive cohort. We built a retrospective cohort study to assess the hazard of new cancer diagnosis (outcome) in people with and without a prior history of stroke (exposure). We used Cox proportional hazard models to estimate the hazard ratio of new cancer diagnosis.

The hazard of newly diagnosed cancer in the first year following an ischemic stroke was about 2.4 times higher as compared to people without stroke after adjusting for socio-demographics and shared risk factors.

Our study adds to the existing evidence that stroke conveys a higher risk of incident cancer diagnosis shortly after the event. Our results open the door for the study of cancer screening strategies in ischemic stroke.