Scientists explain the link between cancer and stroke risk

People with invasive tumors were more likely to have an ischemic stroke than the general population, with the highest risk occurring in the first three months after diagnosis. The association was especially noticeable in pancreatic and lung cancers. About when the risk of stroke after cancer diagnosis is highest and which types of cancer are most associated with it, see the "Izvestia" article.

The most dangerous period is the first three months

Researchers from Israel came to this conclusion after analyzing data from the National Cancer Registry and the National Stroke Registry. The study included 182,221 people over the age of 40 who were first diagnosed with invasive cancer between 2014 and 2021. The researchers tracked cases of first-time ischemic stroke for a year after diagnosis. The results are published in the scientific journal Cancer.

In total, in the first year after cancer was detected, stroke occurred about 80% more often than would be expected based on the indicators in the general population. The absolute figure was 62 cases per 10,000 patients. However, the risk distribution over time turned out to be uneven: it was highest in the first three months after diagnosis — during this period, the incidence of ischemic stroke was 2.5 times higher than expected.

The researchers note that the link between cancer and stroke has already been shown in previous studies, but until now it was not clear enough how quickly the probability of vascular complications changes after diagnosis and which types of cancer are associated with the most pronounced risk. The new work made it possible to evaluate these indicators in a large population and highlight the first months after diagnosis as a particularly important period.

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Which types of cancer have a higher risk?

The most pronounced association was found in patients with pancreatic cancer. In this group, the incidence of ischemic stroke was 5.9 times higher than expected, and the absolute rate was 162 cases per 10,000 people. In lung cancer, the rate was 3.9 times higher than expected. At the same time, the researchers did not find a statistically significant increase in the risk of stroke for breast and prostate cancer.

The risk also varied depending on age and the prevalence of the disease. Among patients aged 40 to 54 years, the incidence of stroke was 3.6 times higher than in the general population, while among people aged 75 years and older it was 1.4 times higher. The authors also found a pronounced dependence on the stage: with localized cancer, the indicator was 1.2, and with metastatic disease it reached 2.8.

Thus, we are not talking about the same risk for all people with cancer: the likelihood of complications varied markedly depending on the type and prevalence of the tumor, as well as the age of the patient.

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Why Cancer can increase the likelihood of stroke

The authors of the study did not set out to establish a mechanism that explains the relationship, so the results do not allow us to say that cancer directly causes stroke. One possible explanation is related to changes in the blood coagulation system that can accompany cancer. In some tumors, the body's tendency to form blood clots increases, which can block blood flow.

Other factors accompanying severe cancer may also be important, but as part of this work, researchers could not separately assess the impact of all cardiovascular risk factors, treatment methods, and medications taken. Therefore, the authors emphasize the need for further research that will help to more accurately determine the causes of the revealed pattern.

According to study author Liebruder, the first months after an oncological diagnosis should be considered as a period of increased attention to the risk of ischemic stroke. This is especially true for patients with pancreatic and lung cancer, as well as people with advanced forms of the disease. The authors believe that a more thorough assessment of cerebrovascular risks may be useful for such groups.