Table 3.

Guideline recommendations for VTE prevention in ambulatory medical oncology patients

Guideline	Recommendations
American Society of Clinical Oncology 2020	Routine pharmacological thromboprophylaxis should not be offered to all outpatients with cancer. (Recommendation type: evidence‐based; evidence quality: intermediate to high; strength of recommendation: strong.) High‐risk outpatients with cancer (KRS ≥2) prior to starting a new systemic chemotherapy regimen may be offered thromboprophylaxis with apixaban, rivaroxaban, or LMWH if no significant risk factors for bleeding and no drug interactions. Provider should discuss with patient the benefits and harms, drug cost, and duration of prophylaxis. (Recommendation type: evidence‐based; evidence quality: intermediate to high for apixaban and rivaroxaban, intermediate for LMWH; strength of recommendation: moderate.) Patients with multiple myeloma receiving thalidomide‐ or lenalidomide‐based regimens with chemotherapy and/or dexamethasone should be offered thromboprophylaxis with either aspirin or LMWH (lower‐risk patients) or LMWH (higher‐risk patients). (Recommendation type: evidence‐based; evidence quality: intermediate; strength of recommendation: strong.)
International Society of Thrombosis and Hemostasis 2019	Suggest apixaban or rivaroxaban for primary thromboprophylaxis in high‐risk ambulatory patients (KRS ≥2) starting chemotherapy if no contraindications or drug‐drug interactions for up to 6 months. Treatment decision should be made after considering the risk of VTE and bleeding as well as patient preferences/values. Suggest LMWH be considered for high‐risk patients with contraindications to apixaban or rivaroxaban.
International Initiative on Thrombosis and Cancer 2019	Primary prophylaxis with LMWH, VKAs, or DOACs is not recommended routinely in ambulatory patients on systemic anticancer therapy (grade 1B). Primary prophylaxis with LMWH is indicated in ambulatory patients with locally advanced or metastatic pancreatic cancer on systemic anticancer therapy who have a low risk of bleeding (grade 1B). Primary prophylaxis with LMWH is not recommended outside a clinical trial for patients with locally advanced or metastatic lung cancer on systemic anticancer therapy (guidance). Primary prophylaxis with DOAC (apixaban or rivaroxaban) is recommended in ambulatory patients on systemic anticancer therapy at intermediate‐to‐high VTE risk, identified by cancer type (i.e., pancreatic) or by a validated risk assessment model (i.e., KRS ≥2), and not actively bleeding or at a high risk of bleeding (grade 1B). In patients treated with immunomodulatory drugs combined with steroids or other systemic cancer therapies, primary prophylaxis is recommended (grade 1A). In this setting, VKAs at low or therapeutic doses, LMWH at prophylactic doses, and low‐dose aspirin have been effective (grade 2C).
National Comprehensive Cancer Network 2020	Consider apixaban or rivaroxaban for up to 6 months in high‐risk patients with cancer (KRS ≥2) starting a new chemotherapy regimen (grade 2A). Recommend LMWH or VKA (INR 2–3) for high‐risk patients with myeloma (IMPEDE‐VTE score >3 points or SAVED score ≥2 points) (grade 2A). Recommend aspirin (81–325 mg daily) or no prophylaxis for low‐risk patients with myeloma (IMPEDE‐VTE score ≤3 points or SAVED <2 points) (grade 2A).
Spanish Society of Medical Oncology 2018	A validated risk assessment model should be used to assess VTE risk at the initiation of systemic therapy and during the evolution of treatment and disease (grade 2C). Routine thromboprophylaxis is not recommended in ambulatory patients with cancer (grade 1B). Thromboprophylaxis with LMWH or DOACs may be considered in high‐risk ambulatory patients with cancer such as those with advanced pancreatic cancer, NSCLC with ROS‐1 and ALK rearrangements, patients with KRS ≥2, or high‐risk according to another validated risk model initiating systemic therapy and no contraindications and low risk of bleeding. No consensus on dose or duration of thromboprophylaxis, but at least 12 weeks is suggested. If DOAC thromboprophylaxis is planned, must assess drug‐drug interactions. Recommend discussing the indication for thromboprophylaxis and the risks and benefits. Patients should be closely monitored (grade 1B). Recommend educating patients about risk factors and symptoms of VTE (grade 2A).

Abbreviations: ALK, anaplastic lymphoma kinase; DOAC, direct oral anticoagulant; INR, international normalized ratio; KRS, Khorana risk score; LMWH, low‐molecular‐weight heparin; NSCLC, non‐small cell lung cancer; ROS‐1, c‐ros oncogene; VKA, vitamin K antagonist; VTE, venous thromboembolism.