The latest guidelines for venous thromboembolism in patients with solid tumors from the Italian Association of Medical Oncology (AIOM) have recently been released. These guidelines summarize literature data regarding the clinical–epidemiological link between solid cancer and thrombosis, and determine the current evidence to be transferred to clinical practice regarding the following aspects:
- Screening for hidden cancer in patients suffering from idiopathic venous thromboembolism
- Venous thromboembolism prophylaxis in cancer patients who have undergone surgery, chemotherapy or hormonal therapy, or have been hospitalized for an acute event
- Venous thromboembolism therapy for patients with solid tumors
- Impact of anticoagulant therapy on prognosis.
The association between cancer and the occurrence of thrombosis has recently become evident from the analysis of patients’ clinical data and has been reinforced by autoptic studies, highlighting a correlation that may have been concealed in the past. Moreover, the cases of relapse of both thrombosis and embolism are higher in cancer patients; patients who suffered from idiopathic thrombosis are at higher risk of developing neoplasia in the first year after the event.
In addition, some conditions typical in patients with cancer (surgery, chemotherapy and hormonal therapy, presence of a central venous catheter) greatly enhance the chances of thrombotic events.
Why are patients with cancer affected by the occurrence of thrombotic events?
The alteration of hemostasis and hemostasis-related players (vascular wall integrity, leukocytes and platelet numbers and activity, and coagulation factors) are typical of the tumor condition and the fact that cancer cells themselves have prothrombotic features, make these individuals better candidates.
Indeed, cancer patients often display an altered level of circulating markers of clotting activation, which so far has not been predictive of thrombotic events in cancer patients.
Here is a summary of the recommendation on prophylaxes:
- The risk of hidden malignancies in patients who have suffered from idiopathic venous thromboembolism is higher compared with patients with secondary venous thromboembolism. The combination of careful anamnesis, hematic tests, mammography or thoracic scan within 1 year from the thrombotic event could be as effective as CT or CT/PET in diagnostic outcome.
- After surgery, the use of low-molecular-weight heparin at a high dose is recommended as the first therapeutic choice, followed by non-fractionated heparin and Fondaparinux. The length of the treatment depends on the presence of risk factors (long length of stay in bed, previous thrombotic events, obesity).
- There is a weak recommendation of an anti-thrombotic prophylaxis in patients subjected to chemotherapy or hormonal therapy. This is mainly due to the lack of well-designed studies that select the patients according to well-defined criteria.
- No specific antithrombotic routine is indicated in patients with a central venous catheter whether an anticoagulant prophylaxis is recommended after hospitalization of a cancer patient with an acute medical event.
- In case of renal failure, the use of non-fractionated heparin is recommended. The anticoagulant therapy must be adjusted according to the platelet count.
- For the length of the anticoagulant treatment and the type of anticoagulant used in case of thrombosis relapse, the guidelines suggest frequent re-evaluation of the state of the patient.
- The influence of the anticoagulant treatment on the prognosis is still controversial and the data published are mainly based on retrospective studies. More prospective ad hoc studies are needed to confirm the positive prognostic role of low-molecular-weight heparin.
Despite the existence of precise indications for the thrombotic prophylaxis, there is a need for further studies to precisely define recommendations for all the clinical settings.
The Italian guideline can be download here.