Thromboprophylaxis for oncology patients

Due to this increased risk of thrombosis, most in-patients should be considered for thromboprophylaxis with enoxaparin as per the LUHD Antithrombotic Guidelines (Adults) (only accessible when connected to intranet) Common exceptions include: 

• Thrombocytopenia (platelet count <50 x 10⁹/L)
• Recent haemorrhage (within last 3 months) or suspected acute haemorrhage.
• Impaired renal function (CrCl <30mL/min) – discuss with haematology if high thrombosis risk.
• Hepatic failure.

Graduated elastic compression stockings (GECS) are effective prophylaxis and can be used in patients unsuitable for LMWH thromboprophylaxis. They are not recommended for prevention of post-thrombotic syndrome in patients with confirmed thrombosis.  They must be avoided in patients with: 

• massive leg oedema 
• peripheral neuropathy 
• severe peripheral vascular disease 
• major leg deformity 
• dermatitis (active/severe) 
• pulmonary oedema.

The following table provides recommended doses of enoxaparin for thromboprophylaxis including dose adjustments for extremes of body weight and renal impairment. Each patient should be considered on an individual basis for bleeding and VTE risk and discussed as necessary.

Due to limited clinical evidence for prophylactic LWMH in extremes of body weight and renal impairment, all doses recommended are ‘off-label’. Monitoring of LMW Heparin assay is recommended (*) only for patients with a body weight >150kg, see section for LMW Heparin level monitoring in the NHSL Guidance.

On inpatient prescriptions, ‘prophylaxis, not for discharge’ should be annotated on HEPMA, to prevent inadvertent continuation in primary care.  In situations where LMWH thromboprophylaxis is to continue in the community, this should be clearly documented by the team on the drug prescription and within the patient’s clinical notes.

Ambulatory out-patients with active cancer, or receiving SACT, should not routinely be offered thromboprophylaxis. However, patients at high risk of thrombosis could be offered thromboprophylaxis with apixaban. 

The AVERT trial evaluated thromboprophylaxis with apixaban 2.5mg bd in patients with a Khorana score of ≥2 who were initiating chemotherapy.  Patients were not recruited if they were receiving targeted therapy, hormonal therapy or immunotherapy alone. Risk of VTE was significantly lower with apixaban than placebo (4.2% v 10.2%, p=<0.001) although an increased risk of major bleeding was observed with apixaban (3.5% v 1.8% with placebo, p=0.046). Major bleeding was primarily observed in patients with GI or gynaecological malignancies. No fatal bleeding occurred. 

The Khorana score does not account for other risk factors such as a thrombophilia or specific chemotherapy regimens with a high risk of thrombosis.  A patient with a Khorana score <2, but with other factors that could increase their risk of thrombosis to >10% could also be considered for apixaban thromboprophylaxis.  The recent British Society for Haematology Guidelines recommend all patients receiving chemotherapy for pancreatic cancer should be offered routine thromboprophylaxis.  Local data suggest an equally high risk of thrombosis in patients with biliary tract cancer.  For other ambulatory patients receiving chemotherapy, apixaban thromboprophylaxis could be considered in patients with:

• Khorana score ≥2. 
• Thrombophilia – if predates malignancy then discuss with patient’s haematologist. 
• Local audit data demonstrating a SACT regimen has a thrombosis risk of >10%  

*The Khorana score was developed in patients receiving chemotherapy. Its relevance for patients receiving other forms of SACT has not been assessed.