Cancer patients face many heightened health risks after their initial diagnosis. While the disease itself is a leading cause of death worldwide, it is critical to consider other conditions that may cause dangerous and potentially fatal complications in cancer patients.
Thrombosis is the second leading cause of death in patients with cancer, after the cancer itself. One in five cancer patients will develop a blood clot; in some of these cancer patients, that clot can prove to be fatal.
Cancer patients are four times more likely than people without cancer to develop a potentially fatal blood clot. Risk factors that increase the incidence of thrombosis include the type of cancer, the cancer treatment, the patient’s Body Mass Index (BMI), age, smoking history, lifestyle (active or sedentary), and more. For example, a patient with pancreatic cancer is at a greater risk of experiencing a blood clot compared to someone with breast cancer. Cancer patients who are overweight are more at risk than those with a normal BMI, and patients who need to be treated with surgery are at greater risk than patients being treated with chemotherapy alone.
As a result, it is crucial to evaluate a patient’s numerous risk factors before deciding whether their cancer alone poses the greatest threat to their lifespan and quality of life, or if it is their risk of developing a fatal blood clot. In general, bleeding risk should also be considered as patients with cancer have an increased risk of bleeding with anticoagulation than patients without cancer on anticoagulation, although the risk of a recurrent blood clot is higher than the risk of bleeding. Since cancer is often treated with a multi-modality treatment method, an oncologist may decide to treat with chemotherapy to shrink a patient’s tumor before opting for surgery. Some types of treatments are also associated with an increased risk for developing a blood clot, including radiation and immunotherapy.
Identifying Personal Risk
As modern medicine continues to advance, so do our capabilities for evaluating someone’s risk factors prior to deciding on a treatment plan. Recent studies have selected cancer patients based on their Khorana Risk Assessment Score to further evaluate whether the score is an accurate predictor of their risk for developing a blood clot. For someone recently diagnosed with cancer, this risk prediction score uses a number of factors to determine if they have a low, intermediate or high risk of developing a blood clot. Essentially, it identifies a patient’s baseline risk for developing thrombosis based on cancer type, some lab test results, and BMI. Since a patient’s risk of developing thrombosis is one of the most overlooked related conditions, this assessment score gives medical practitioners a way to determine if patients would benefit from starting low dose anticoagulation to prevent blood clots before they develop.
The Khorana Risk Assessment Score is a key validated tool in the thrombosis and cancer space. Within the last decade, there has been a huge shift in cancer prognoses because of treatment advancements. Direct oral anticoagulants (DOAC) are proven to prevent the formation of blood clots and to treat blood clots in cancer patients. According to studies published in the last five years, DOACs are an effective treatment for thrombosis in cancer patients, compared to the previously used low molecular weight heparin, decreasing the burden of the need for daily injections.
As we look ahead, it is likely that the medical community will begin to actively identify high risk patients to prevent clots from ever forming, using DOACs at a lower dose than the treatment dose. It is crucial to try and prevent thrombosis in these patients, as blood clots may delay chemotherapy or cause other complications which can affect their cancer treatments.
The Path Forward
In addition to medical advances and appropriate medical assessment, patient advocacy and awareness is also a key element of prevention and early identification. The World Thrombosis Day campaign, dedicated annually on October 13, spreads life-saving awareness about the signs, symptoms, and risk factors for thrombosis. Patients can advocate for their own well-being by informing medical professionals of their family health history, personal risk factors and normal physical state.
It is equally important for primary care doctors and oncologists to be cognizant of the heightened risk factors for cancer patients and be diligent in informing them of all these risks to ensure they understand their treatment and can take proper precautions and preventative measures.
Taking Preventative Action
Awareness has the power to prevent the occurrence of thrombosis in patients with cancer. As cancer treatments improve, patients are living longer with cancer. However, as cancer evolves into more of a chronic condition, patients are at risk of developing related conditions for a much longer period. If you or someone you know has cancer, resources like this, from World Thrombosis Day, can ensure you are prepared to combat the second leading cause of death for cancer patients.
Jean Connors, M.D., is a hematology attending physician at Brigham and Women’s Hospital and Dana Farber Cancer Institute; the Medical Director of the Anticoagulation Management Services, and the Hemostatic Antithrombotic Stewardship Program; and an Associate Professor of Medicine at Harvard Medical School. She is also a Scientific Steering Committee member for the World Thrombosis Day Campaign.
She received a medical degree from The Johns Hopkins University in Baltimore, MD, completed her residency in internal medicine at Beth Israel Deaconess Medical Center in Boston, MA, as well as fellowships in transfusion medicine and hematology and oncology from Brigham and Women’s Hospital.
Dr. Connors is an Associate Editor for the Journal of Thrombosis and Haemostasis (JTH) and she is a member of many professional societies, including the American Society of Hematology (ASH) and the International Society on Thrombosis and Haemostasis (ISTH). She has participated in numerous clinical trials for patients with venous thrombosis in cancer and anticoagulation questions in general.
