Synopsis
Recognise venous thromboembolism in a high-risk cancer population, confirm it with the correct first-line imaging and individualise anticoagulation around bleeding, thrombocytopenia, interactions, procedures and ongoing tumour activity.
- Cancer increases thrombosis through tumour procoagulants, inflammation, platelets, stasis, surgery, systemic therapy and central venous devices; risk persists while cancer is active.
- Key presentations are unilateral leg or arm swelling and pain, unexplained breathlessness, pleuritic pain, haemoptysis, syncope or catheter dysfunction; fever does not exclude clot.
- First-line DVT imaging is proximal leg-vein ultrasound and first-line PE imaging is CTPA when suitable; D-dimer is often raised by cancer and is useful only within a validated low-probability algorithm.
Key red flags
Hypotension, rising lactate, syncope, severe hypoxaemia or right-ventricular strain suggests high-risk pulmonary embolism.
Unexplained dyspnoea, pleuritic pain, tachycardia, hypoxaemia, haemoptysis or syncope can occur with a normal chest examination.
Investigation priorities
Confirm or exclude clinically suspected proximal lower-limb DVT without contrast or radiation.
Demonstrate pulmonary arterial thrombus and assess right heart and alternative thoracic causes.
Management branches
A cancer patient develops a compatible limb, chest or catheter symptom.
- Assess haemodynamic and bleeding risk, use the validated DVT or PE probability pathway and obtain ultrasound or CTPA without attributing symptoms automatically to malignancy.
- Start interim therapeutic anticoagulation if clinical probability is significant and imaging is delayed, after platelet, renal, bleeding and procedure assessment.
Key medicines
ApixabanGive 10 mg orally twice daily for 7 days, then 5 mg twice daily for treatment of acute DVT or PE; any reduction after 6 months is a deliberate recurrence-versus-bleeding decision under the cancer thrombosis plan.
Low-molecular-weight heparinUse the product-specific weight-based treatment regimen; for dalteparin in cancer-associated VTE a licensed course uses 200 IU/kg subcutaneously once daily for the first 30 days, then approximately 150 IU/kg once daily for months 2 to 6, subject to product maximums and platelet or renal adjustment.