Thousands of patients are surviving cancer every year only to die from blood clots that may have been brought about by their treatment, according to a report by MPs.

Blood clots, or venous thromboembolism (VTE), are a known risk for cancer patients. Both the cancer itself and the chemotherapy that patients undergo increase the danger. Hospitals should warn patients and take action to safeguard them. And yet, says a report from the all-party parliamentary thrombosis group, 4,000 cancer patients die every year with a blood clot identified on the death certificate as a joint cause of death.

“It is a tragedy that in today’s NHS a patient can beat their cancer, only to then die of a clot,” said Andrew Gwynne MP, chair of the group. “We hope that by raising awareness of this overlooked issue, we can drive up patient safety and provide better outcomes for patients.”



The group, supported by the charity AntiCoagulation Europe, gathered data on blood clots on the death certificates of cancer patients through freedom of information requests to hospital trusts in England and Wales: of 157 trusts, 92 responded.

They found that out of all the cancer patients who died in the past three years, 2.6% had VTE recorded as one of the causes of death. That amounts to 3,988 deaths a year, although it is not possible to say whether it was the cancer or the blood clot that was primarily to blame.

Only 41% of trusts had policies in place for the management of patients undergoing chemotherapy with suspected blood clots. Just under half gave cancer patients written and verbal warnings about the risks, so that they could watch out for the danger signs.

Blood clots are more likely in some cancers than in others. Patients with brain, lung and bladder cancers were more likely to die with a blood clot – the rates last year were 2.6%, 2.5% and 2.3% respectively. The incidence was higher in some areas than in others, from 2% in the south of England to 3.6% in Wales.

The risk of a blood clot rises in cancer patients because they tend to have a higher number of platelets and clotting factors in their blood, which can clump together to plug damaged blood vessels and stop bleeding. Chemotherapy drugs kill cancer cells, which may then release substances that promote clotting. It is well known that the breast cancer drug tamoxifen, which many women take for five years after surgery, can cause thromboembolism, although the benefits outweigh the risks.

Surgery and chemotherapy can also damage the walls of blood vessels, increasing the risk. There are also dangers for cancer patients who may be feeling ill because of their treatment in sitting or lying down a lot of the time.

“It is not always widely known that cancer patients have a four- to sevenfold increased risk of developing a blood clot compared with the general population,” said Eve Knight, co-founder and chief executive of AntiCoagulation Europe. “It is vital that we raise awareness of this and the importance of staying on the medication to treat the blood clot for at least six months in order to prevent unnecessary deaths.”