Breast cancer patients face 59% higher stroke risk during first year, study finds

Women newly diagnosed with breast cancer have a 59 per cent higher risk of ischaemic stroke in the first year after diagnosis, research suggests.

Researchers also said survivors who develop sudden stroke symptoms, including one-sided weakness, facial drooping, speech difficulties or vision loss, should seek immediate medical attention.

The multicentre study analysed National Health Insurance Service data from 107,606 women who underwent surgery for newly diagnosed breast cancer and compared them with 322,818 age-matched women with no history of cancer.

The research was conducted by professor Shin Dong-wook of Samsung Medical Center, professor Han Kyung-do of Soongsil University, professor Yong-Moon Mark Park of the University of Arkansas for Medical Sciences and professor Wonyoung Jung of the University of Pennsylvania.

Professor Yong-Moon Mark Park said: “The study demonstrates a time-dependent pattern in which the risk of ischaemic stroke rises sharply immediately after breast cancer diagnosis and treatment before gradually declining.

“The key finding is that we evaluated stroke risk according to different stages following diagnosis and treatment. This suggests that clinicians should consider not only how much the risk increases, but also when it is greatest.”

The study included women aged 18 or older who were newly diagnosed with breast cancer between 2010 and 2016, underwent surgery and had no previous stroke.

Each patient was matched with three women of the same birth year who did not have cancer. Participants were followed for an average of 7.2 years.

The main outcome was ischaemic stroke, also known as cerebral infarction. It occurs when a blocked blood vessel cuts off blood flow to the brain and is a leading cause of death and long-term disability.

During follow-up, ischaemic stroke occurred in 1,155 breast cancer patients, or 1.07 per cent, and 3,698 women in the control group, or 1.15 per cent.

Overall, breast cancer surgery was not linked to a significantly higher long-term risk of ischaemic stroke, and researchers recorded a slight fall in risk over time.

However, a different pattern emerged immediately after diagnosis.

Within one year of diagnosis, patients had a 59 per cent higher risk of ischaemic stroke than women without cancer.

The risk was highest during the first three months, at 2.90 times that of the control group.

It remained elevated within six months, at 2.27 times the control group’s risk, before gradually declining.

The risk was still 17 per cent higher three years after diagnosis.

Researchers said the temporary increase may be linked to cancer-related hypercoagulability, inflammatory responses to surgery and treatment, and cardiovascular stress caused by anticancer therapies.

Hypercoagulability means the blood is more likely than usual to form clots. Cardiovascular refers to the heart and blood vessels.

The increased risk was particularly pronounced among patients with hypertension, type 2 diabetes or a history of current smoking.

Hypertension means high blood pressure. Type 2 diabetes is a long-term condition affecting how the body controls blood sugar.

Breast cancer patients who smoked had a 2.26-fold higher risk of ischaemic stroke than comparable women without cancer.

Principal researcher professor Shin Dong-wook stressed the importance of vigilant care for patients with cardiovascular risk factors, especially during the early phase of breast cancer treatment.

Shin said: “Patients with hypertension, diabetes, or other cardiovascular risk factors, as well as those who smoke, require particularly careful management during the early phase of breast cancer treatment.

“If patients who have undergone breast cancer treatment suddenly develop weakness in one arm or leg, facial drooping, slurred or abnormal speech, or vision loss on one side, ischaemic stroke should be suspected, and they should seek immediate medical evaluation.”

Researchers said survivorship care should include strategies to monitor and manage cardiovascular and cerebrovascular disease risk throughout treatment as advances in breast cancer care continue to improve survival.

Cerebrovascular disease refers to conditions affecting blood flow and blood vessels in the brain.