ASCO recommends that doctors determine the risk of a blood clot for all patients, especially before starting or changing chemotherapy. ASCO also recommends the following for preventing and treating blood clots for patients with cancer:

• Most patients with cancer who are in the hospital should receive treatment with an anticoagulant to prevent blood clots during their hospital stay.
• Many patients who have to stay in the hospital for just a few days, such as for a minor procedure, do not need blood clot prevention, except for those patients who have a high risk of blood clots.
• To prevent blood clots, heparin or low doses of aspirin are recommended for patients with multiple myeloma who are receiving both antiangiogenic drugs and chemotherapy and/or the drug dexamethasone (multiple brand names).
• Patients who will have major surgery for cancer should receive treatment to prevent blood clots before surgery, continuing for at least seven to ten days after surgery. Treatment may continue for up to four weeks for patients who have a higher risk of blood clots.

Heparin is recommended to treat DVT and PE for the first five to ten days, as well as long-term (longer than six months) prevention of blood clots.