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Transcript: Thrombosis

Last updated:20th May 2024
Published:20th May 2024

Dr Gary Lyman

All transcripts are created from interview footage and directly reflect the content of the interview at the time. The content is that of the speaker and is not adjusted by Medthority.


Yeah, cancer-associated thrombosis has emerged as a another very important adverse event associated with cancer therapies. Both, again, traditional cytotoxic therapies, and some of the newer novel therapies. And, in fact, our own data would suggest, after the cancer, cancer-associated thrombosis, as well as febrile neutropenia, are the second leading cause of mortality in patients receiving cancer chemotherapy.
So, it has emerged as a very important factor. Some 15 years ago, we launched the first guidelines on this topic from the American Society of Clinical Oncology, for guiding both the prevention and treatment of patients with cancer-associated thrombosis. We developed the major risk model that's now used globally, and both within guidelines, but also for determining clinical trial eligibility for high-risk patients.
This is called the Khorana score, and it's based on the type of cancer, the body mass index, patients with a low haemoglobin, or the use of a potent alpha, as well as patients with high white blood count or platelet count, and all this assessed prior to chemotherapy. And, this risk tool has, again, been extensively validated globally.
So, the traditional approach to treating and preventing chemotherapy-induced thrombosis, venous thromboembolism, has been the use of low-molecular-weight heparins. Of course, even early on, the use of unfractionated heparin was used, but it's pretty much been replaced by the low-molecular-weight heparins, which are effective and safe. However, they require daily injections. And, the most recent version of the clinical practice guidelines have integrated the newer agents, what we call, the direct oral anticoagulants, or DOACs, as effective and generally safe options for patients with cancer who are at particularly high risk for cancer-associated thrombosis.
There are remaining issues around these new oral agents. Although they've, of course, improved compliance and are favoured by patients, they do pose a greater risk of drug-drug interactions, as well as in some cases, GI bleeding. So, it's important that the clinician who's considering whether to use a low-molecular-weight heparin or a DOAC, an oral agent, in high-risk patients with a score of three or greater, consider, again, this potential for drug-drug interactions or GI bleeding, particularly in patients with upper gastrointestinal malignancies. The guidelines also recommend considering prophylaxis with these agents in those with a Khorana score of two, low risk as opposed to very... excuse me, high risk, as opposed to very high risk for the three or greater patients. But, it's also very clear that the majority of patients will be at lower risk for venous thromboembolism. And, the guidelines currently recommend no prophylaxis with these agents, both because of the risk of major bleeding, although uncommon, it does occur, and, of course, the cost and inconvenience associated with these agents.
So, pretty much consistent recommendations across the guidelines, again, including the American Society of Clinical Oncology, the European Society of Medical Oncology, the NCCN here in the US, all of them pretty much recommend appraising the risk based on a validated risk score and then targeting the very high-risk patients, and now those with a chronic score of two with either a low-molecular-weight heparin or with an oral anticoagulant. And, then not using these agents in patients at lower risk. And with this, we hope that this will become much less of a issue compromising patients' quality of life and clinical outcomes.

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