Venous thromboembolism in cancer patients

Though there is a relative lack of high level evidence regarding this condition we do know that it differs in important ways from VTE in the general population. Below are some key points from a recent review.


Initial treatment

Acceptable alternatives include low molecular weight heparin (LMWH), unfractionated heparin (UFH), and fondaparinux. LMWH seems to be associated with a mortality benefit and is favored over the other two.


Thrombolysis

Little evidence exists to guide clinicians. Though special vigilance is needed to exclude patients with cancer associated bleeding risks (eg CNS involvement) patient selection in general is similar to that in the general population.


Continued management after the first few days

Here is where we have the best evidence. Several open label RCTs and a meta-analysis favor LMWH over warfarin for the next 3 to 6 months at least if the patient has normal renal function.


Duration of treatment

Cancer patients have an increased risk of recurrent VTE on and off treatment. They also have an increased risk of anticoagulant related bleeding in many circumstances. The review states that extended anticoagulation (beyond 3-6 months) “be considered” in this population. So just as with the ACCP guideline recommendation on this question for the general VTE population, considerable wiggle room is given for clinician judgment and patient preference.


IVC filters

IVC filters are thrombogenic and even more so in cancer patients. The review authors recommend against IVC placement unless there is an acute VTE with contraindication to anticoagulation, which is consistent with the more conservative of the various guidelines for the general population.


Management of recurrent VTE while on treatment

True anticoagulant failure is believed to be rare in the general population but according to the review is common in the setting of cancer. Strategies to deal with this situation involve first ruling out HIT, non compliance or subtherapeutic anticoagulation. In the event of true anticoagulant failure increasing the intensity of anticoagulation is recommended, either by switching to a superior anticoagulant or increasing the dose of the existing anticoagulant. An algorithm is presented in the review.


Novel oral anticoagulants

The authors recommend against the use of these agents in cancer associated VTE until more research evidence is available.