EXPERT COMMENT
Normalising cancer associated thrombosis
Professor Simon Noble discusses the importance of normalising cancer associated thrombosis among cancer patients and the steps pharmacists can take to avoid patient distress
The first time I became aware of the association between cancer and thrombosis was as a junior doctor , when I admitted a patient who had developed atrial fibrillation caused by a pulmonary embolism ( PE ). I noticed that the patient had painless jaundice – a tell-tale sign of pancreatic cancer , which a scan confirmed .
As I went on to do some oncology and palliative care , I realised that cancer associated thrombosis ( CAT ) was a massive problem in our population that was not being managed properly . Even today , 20 years later , there is still significant work to do in raising awareness of the condition .
With this in mind , there are two main areas I want to discuss in this piece :
The first is the crucial role that pharmacists can play in increasing cancer patients ’ awareness of thrombosis . Pharmacists have an integral role in the administration of anti-cancer therapies and information giving ahead of cancer treatment . This is the best time to share additional information about the risk and symptoms of thrombosis .
The second is to ensure the safe prescribing of anticoagulants for patients who have been diagnosed with CAT . That is , giving information on how specific drugs should be taken and ensuring that there are no significant drug – drug interactions with anti-cancer therapies .
The risk of CAT for cancer patients Thrombosis is the second leading cause of death in cancer patients , second only to cancer progression . 1 Cancer patients are at very high risk of developing thrombosis for several reasons .
First , the tumours themselves secrete procoagulants , which makes the blood stickier . However , different cancers have different thrombotic effects . For instance , pancreatic cancer , primary brain cancer , and lung cancer can increase the risk of thrombosis twentyfold . 2 Other cancers , such as breast cancer and prostate cancer , are less thrombotic but we see more of these patients with clots because these are such common cancers .
8 | Issue 101 | hospitalpharmacyeurope . com
The pharmacy community has an integral role in the management of CAT , starting with the patient who is receiving systemic treatments
Simon Noble MD FRCP Marie Curie Professor in Supportive and Palliative Medicine , Division of Population Medicine , Cardiff University , UK
Disease progression is another factor which makes the cancer patient at greater risk of thrombosis . Patients with metastatic disease will have a twentyfold increase in risk of developing CAT compared to someone with early-stage cancer . 3
We also have the impact of systemic anti-cancer therapies ( SACT ). Chemotherapies , targeted therapies , immunotherapies , and all the newer agents increase the risk of CAT . A patient ’ s risk of developing a blood clot with stage one breast cancer is 0.2 % – only double the risk of a healthy person developing a clot . However , if you give that breast cancer patient adjuvant chemotherapy , which we commonly do , that risk increases tenfold to 2 %. 4 Around 55,000 women and 370 men are diagnosed with breast cancer every year in the UK , so that is a lot of clots . 5
A period of immobility , dehydration or an infection can increase the thrombotic risk further . This leaves us with a patient with an underlying high risk of cancer and any illness can tip them over the threshold until they develop a clot .
The evidence for prevention of clots Despite the prevalence of CAT , the evidence for prevention of clots in ambulant cancer patients receiving SACT is unclear . There are certain cancers known to be so thrombotic when treated that we should be giving prophylaxis . For example , haematologists will routinely give primary thromboprophylaxis to patients with myeloma receiving lenalidomide and steroids , because we know up to 25 % of these patients would get a clot otherwise . 6 There are also strong data to recommend the use of primary thromboprophylaxis in pancreatic cancer patients receiving chemotherapy . However , despite it being in the National Institute for Health and Care Excellence ( NICE ) guidelines , the uptake of this in clinical practice in the UK is still poor .
In terms of risk assessment tools , the Khorana Score can tell us which patients are at higher risk of venous thromboembolism ( VTE ). It assesses patients according to primary cancer , platelet count , haemoglobin , and