An accompanying editorial notes that residual vein thrombosis (RVT), measured by compression ultrasound, reflects venous stasis and vessel wall damage; two important components in the pathogenesis of venous thrombosis. In this study the researchers measured RVT after six months of low molecular weight heparin (LMWH) to guide the duration of therapy, in a population of patients with active cancer and a first DVT. Those with no RVT stopped treatment at 6 months and were followed for a further 12 months; this group had a low rate of recurrent VTE (2.8%). For those with RVT, the rate of recurrent VTE was 18% in those randomised to a further six months of LMWH compared to 22% in those who stopped treatment (no statistically significant difference between the two strategies).
The editorial considers the limitations of the current study, including the open-label nature, small sample size and the different lengths of follow-up for treatment groups, and the authors note that reproducibility of the RVT test is a potential source of variability of recurrence. Another important point to consider is the generalisability of the results, as anyone who had not reached the 6-month point following their initial thrombotic event (including any patients who developed recurrence or had a bleed whilst on anticoagulants) would not have been included. The authors conclude that further research is required to define the utility of RVT for guiding the optimal duration of anticoagulant therapy in a patient with cancer with VTE.
A ‘Grand Round’ article discussing extended anticoagulation for the treatment of cancer-associated DVT has also been published and is available via the link below.