MMI Blood clots in multiple myeloma: Why they happen and how they are treated

MMI Blood clots in multiple myeloma: Why they happen and how they are treated

Danielle Barron reports

Danielle Barron talks to SpR Dr Dawn Swan about the rare but very real risk of thrombosis for multiple myeloma patients

How significant is the risk of thrombosis for people with multiple myeloma?

It’s not well understood in a lot of ways. We know that all cancer types have an increased risk of thrombosis and myeloma patients seem to have a particularly high risk. It isn’t as high as some types such as pancreatic cancer, but it is significant. Even with thromboprophylaxis during treatment, you would expect that roughly 10% of patients would experience pulmonary embolism (PE) or deep vein thrombosis (DVT) or some kind of clot. Every patient with multiple myeloma is at risk especially at the start when their disease is most active but the risk falls when they are in remission.

Why is the risk of thrombosis an issue?

The risk is multifactorial. It is related to factors of the disease itself. The paraprotein can affect clotting and there are factors that are independent of that. On top of that, the treatments can affect a patient’s risk too. Certain treatments will increase the risk more than others.
Steroids can slightly increase risk, but the most “sticky” are the immunomodulatory drugs. These are the big thing when it comes to clotting. One of these agents such as lenalidomide or pomalidomide on its own as a single agent isn’t too bad and if you add in a low-dose steroid that’s mostly okay too. It’s when you add in a high dose steroid, they all start clotting, and if you add in chemotherapy or other agents on top of that the risk becomes quite significant.

It also depends on the status of the disease; if you’ve got somebody presenting for the first time, their risk will be higher than someone who has relapsed. Somebody in remission will have a lower risk, but that will still be higher than the general population.

How is this risk managed – are patients given preventative treatment?

The way that it has been managed hasn’t changed too much over the years. Guidance published in 2008 suggested that patients on an immunomodulatory agent plus a steroid, and with any other risk factors for thrombosis such as immobility, obesity, prior history of DVT, then they ought to be on low molecular weight heparin at the very least and if not possible then they should have aspirin.

Even when we give prophylaxis, we still see a rate of thrombosis of around 20%, no matter what you do. We are still trying to determine how we can predict which patients are at abnormally high risk and those that would be standard high risk, as well as the best way of treating them. From studies in cancer patients, we know that warfarin isn’t great and patients tend to have a higher recurrence rate with warfarin. We also know that heparin is more efficacious than aspirin, but it would be nice not to have to inject patients every day so there are a lot of studies going on looking at the new oral anticoagulants in cancer patients. This would be a nicer option for patient so I am hopeful that going forward this would become the standard.

What is the bottom line for multiple myeloma patients when it comes to thrombosis risk?

It’s something for all patients to be aware of. They need to keep active, stay hydrated; if they go on a flight they need to walk around. They also should talk to their consultant about what medication they are on; there is a tendency for patients to be given aspirin who may actually need stronger prophylaxis.

Patients should always be aware of the signs and symptoms of a DVT; any swelling or redness of one leg, if was painful, or with PE, if they got acute shortness of breath or chest pain. They should always get those symptoms checked out.

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