Venous Thromboembolism Prophylaxis and Treatment in Adults with Cancer

Publication Date: April 19, 2023
Last Updated: May 31, 2023



  • This patient guideline summarizes key takeaways from American Society of Clinical Oncology (ASCO) guidelines for Venous Thromboembolism Prophylaxis and Treatment in Patients with Cancer. The purpose of this guideline is to provide updated recommendations about prophylaxis and treatment of venous thromboembolism (VTE) in adult patients with cancer.

  • Venous thromboembolism (VTE) is a term that refers to blood clots in the veins.

  • There are two types of VTE:
    • Deep vein thrombosis (DVT) - a clot in a deep vein, usually in the leg, but sometimes in the arm or other veins.
    • Pulmonary embolism (PE) - this occurs when a DVT clot breaks free from a vein wall, travels to the lungs and then blocks some or all of the blood supply.

  • VTE is a major cause of health issues and death in patients with cancer.

  • Patients with cancer:
    • are significantly more likely to develop VTE than people without cancer.
    • have higher rates of VTE recurrence and bleeding complications during VTE treatment than patients without cancer.

  • The goal of VTE management is to reduce the risk of VTE or VTE recurrence. VTE comprehensive management includes a combination of prevention strategies and treatment strategies when VTE is present. Prevention of VTE is referred to as VTE prophylaxis, and treatment of VTE is referred to as anticoagulation.

VTE Risk Assessment

VTE Risk Assessment

Your care team should help you learn as much as possible about VTE. This includes understanding situations which may increase your VTE risk, such as major surgery, hospitalization, and certain types of medications. (, , )

There is substantial variation in the risk of VTE between individual cancer patients and cancer settings. (, , )

Your care team should assess you for VTE risk initially, and then periodically afterwards. (, , )

VTE Risk should also be assessed when starting certain medications, such as systemic antineoplastic therapy, (a type of cancer treatment) and any time there is a hospitalization. (, , )

In the ambulatory (non-hospital) setting, among patients with solid tumors treated with systemic therapy, risk assessment can be conducted based on a validated risk assessment tool. This is also called a "Khorana score" (see Table 1). These factors include: the site of your cancer, your platelet count, your hemoglobin level, your prechemotherapy leukocyte count, and your your body mass index (BMI). By using a predictive model (seen here), your care providers can determine whether you fall into high, intermediate or low risk categories. (, , )

Table 1. Khorana Score Predictive Model for Chemotherapy-associated VTE in the Ambulatory Setting

Having trouble viewing table?
Patient Characteristic Points
Site of cancer: Very high risk (stomach, pancreas) 2
Site of cancer: High risk (lung, lymphoma, gynecologic, bladder, testicular, renal) 1
Pre-chemotherapy platelet count ≥350,000/µL 1
Hemoglobin level <10g/dL or use of red cell growth factors 1
Pre-chemotherapy leukocyte count >11,000/µL 1
Body mass index ≥35 kg/m2 1

Calculate the total score, adding points for each criterion in the model.

High-risk = if the score is greater than or equal to 3 points
Intermediate risk = if the score is either 1 or 2 points
Low-risk = 0 points

Prevention of VTE

Prevention of VTE

Hospitalized Patients

Most patients with active cancer who are in the hospital may be offered medication to prevent VTE. (, , )
The exception is if you are only in the hospital for a minor procedure or chemotherapy infusion, or if you have any medical conditions that would prevent you from being able to take the VTE prophylaxis medication. Examples of those who should not take the medication include those who are currently receiving stem cell or bone marrow transplants.

Non-Hospitalized Patients

For most patients with active cancer who are not in the hospital, VTE prophylaxis is not required. (, , )
The exception is if you have active cancer, and are considered "high risk". If you are high risk, and do not have any contraindications to the medication, VTE prophylaxis may be offered before you start a new chemotherapy regimen. The recommended medications for VTE prophylaxis are apixaban, rivaroxaban, or low-molecular-weight heparin (LMWH).
Patients with multiple myeloma receiving thalidomide- or lenalidomide-based regimens with chemotherapy and/or dexamethasone should be offered VTE prophylaxis. (, , )
If you have a lower risk you can take aspirin or LMWH. If you are at a higher risk you can take LMWH.

Before A Major Surgery

All patients with active cancer who have major surgery planned should be offered medications for VTE prophylaxis before surgery. The recommended medications are unfractionated heparin (UFH) or LMWH, unless contraindicated. (, , )
In addition to taking VTE prophylaxis medications prior to surgery, mechanical prophylaxis may also be added. Mechanical methods include intermittent pneumatic compression, graduated compression stockings, and venous foot pumps. (, , )
Unless you are unable to take medication because of contraindications, mechanical methods of VTE prophylaxis should not be used by themselves. They should be an addition to medical prophylaxis. The combination of medication and mechanical methods may improve overall effectiveness, especially if you fall into the higher risk category. (, , )

After A Major Surgery

Most patients should continue taking VTE prophylaxis medications for an additional 7-10 days after their surgery. (, , )
Certain patients may need extended prophylaxis, which means that VTE prophylaxis medications should be taken for up to four weeks after surgery. (, , )
Examples of patients who may require extended prophylaxis are patients who had major open or laparoscopic abdominal or pelvic surgery and have high-risk features, such as restricted mobility, obesity, history of VTE, or with additional risk factors.
The recommended medications for patients who need extended prophylaxis are either LMWH, or rivaroxaban or apixaban after an initial period of LMWH or UFH. (, , )
In lower-risk settings, the decision on the duration of VTE prophylaxis medication post-surgery should be made on a case-by-case basis. (, , )

Treatment of VTE

Treatment of VTE

Initial Treatment

Initial anticoagulation medications for established VTE may include LMWH, UFH, fondaparinux, rivaroxaban, or apixaban. (, , )
For patients with cancer and newly diagnosed VTE without severe kidney problem, LMWH is preferred over UFH for the initial 5 to 10 days of anticoagulation. (, , )

Long-Term Treatment

For long-term anticoagulation, LMWH, edoxaban, rivaroxaban, or apixaban for at least 6 months are preferred over vitamin K antagonists (VKAs). VKAs may be used if LMWH or direct factor Xa inhibitors are not available. (, , )
Direct factor Xa inhibitors are more effective than LMWH for reducing thrombosis, but they come with greater bleeding risks. This is especially true in patients with certain types of cancer or co-occurring conditions, and those taking certain medications. Talk to your care provider prior to starting factor Xa inhibitors
Anticoagulation with LMWH, direct factor Xa inhibitors, or VKAs beyond the initial 6 months may be a therapeutic option for some patients with active cancer, such as those with metastatic disease or those receiving chemotherapy. (, , )
Anticoagulation beyond 6 months needs to be assessed on an intermittent basis to ensure a continued favorable risk-benefit profile.

Vena Cava Filters

Vena cava filters are not recommended for:
  • patients with established or chronic thrombosis (VTE diagnosis more than 4 weeks ago)
  • patients with temporary contraindications to anticoagulant therapy (e.g., surgery).
(, , )
There also is no role for filter insertion for primary prevention or prophylaxis of PE or DVT due to concerns for long-term harm.
Vena cava filters may be a therapeutic option for patients with absolute contraindications to anticoagulant therapy in the acute treatment setting (VTE diagnosis within the past 4 weeks) if the condition is considered life-threatening. (, , )
The insertion of a vena cava filter may be a therapeutic option as an add-on to anticoagulation in patients with progression of thrombosis (recurrent VTE or extension of existing thrombus) despite previous anticoagulant therapy. (, , )

Special Populations

For patients with established VTE and primary or metastatic cancers located in the brain or spinal cord, anticoagulation therapy is a therapeutic option. (, , )
Uncertainties remain about the choice of medications and which patients may benefit most.
Treatment of incidental PE and deep vein thrombosis should be treated in the same manner as symptomatic VTE. (, , )
Treatment of isolated subsegmental PE or splanchnic or visceral vein thrombi diagnosed incidentally should be offered on a case-by-case basis. (, , )
The decision for treatment should be made after considering the potential benefits and risks of anticoagulation.
Anticoagulant use is not recommended to improve survival in patients with cancer without VTE. (, , )


  • DVT: Deep Vein Thrombosis
  • LMWH: Low Molecular Weight Heparin
  • PE: Pulmonary Embolism
  • UFH: Unfractionated Heparin
  • VKA: Vitamin K Antagonist
  • VKAs: Vitamin K Antagonists
  • VTE: Venous Thromboembolism

Source Citation

Key NS, Khorana AA, Kuderer NM, Bohlke K, Lee AYY, Arcelus JI, Wong SL, Balaban EP, Flowers CR, Gates LE, Kakkar AK, Tempero MA, Gupta S, Lyman GH, Falanga A. Venous Thromboembolism Prophylaxis and Treatment in Patients With Cancer: ASCO Guideline Update. J Clin Oncol. 2023 Jun 1;41(16):3063-3071. doi: 10.1200/JCO.23.00294. Epub 2023 Apr 19. PMID: 37075273.

Key NS, Khorana AA, Kuderer NM, Bohlke K, Lee AYY, Arcelus JI, Wong SL, Balaban EP, Flowers CR, Francis CW, Gates LE, Kakkar AK, Levine MN, Liebman HA, Tempero MA, Lyman GH, Falanga A. Venous Thromboembolism Prophylaxis and Treatment in Patients With Cancer: ASCO Clinical Practice Guideline Update. J Clin Oncol. 2020 Feb 10;38(5):496-520. doi: 10.1200/JCO.19.01461. Epub 2019 Aug 5. PMID: 31381464.


The information in this patient summary should not be used as a substitute for professional medical care or advice. Contact a healthcare provider if you have questions about your health.