Results of classical anticoagulant therapy in cancer patients with venous thromboembolism (VT) are highly discussed. We retrospectively analysed the outcome of 43 patients with VT and cancer: 32% developed specific complications during either i.v. heparin therapy (10 +/- 0.9 days) or treatment by antivitamin K (106 +/- 14.9 days). Recurrence of thromboembolism (16%) and/or hemorrhages (16%) were much more frequent than in patients without cancer, underlying need for alternative therapy in cancer patients with VT.