Superficial venous thrombosis (SVT) is very common in clinical practice. What's more, around 15- 20% of SVTs occur in the context of cancer. Today, cancer patients are excluded from therapeutic trials for DVT. There is therefore no high-level evidence-based treatment recommendation for these patients. Recent data suggest that the course of cancer-associated DVT is similar to that of cancer-associated deep vein thrombosis (DVT). However, there are currently few prospective data on the evolution of cancer-associated DVT in relation to the treatment used. Due to the absence of clear recommendations of treatment in case of SVT associated with cancer the investigators will perform a prospective observational study to evaluate the efficacy of different regiment of anticoagulant treatment ordered in clinical practice.

Inclusion Criteria:

• Patient over 18
• Patient affiliated to a social security scheme
• Patient who understands French
• Patient with superficial venous thrombosis of the lower and upper limbs confirmed by a Doppler ultrasound less than one month old.
• Patient with active cancer:
• Cancer treatment within the last 6 months,
• Detectable tumor disease, cancer treatment within the last 6 months, ongoing hormone therapy for cancer, palliative cancer.
• The patient has received potentially non-curative cancer treatment (notably palliative chemotherapy).
• Progression shows that the cancer treatment was not curative (due to recurrence or progression under treatment) (particularly in the case of recurrence after surgery)

Exclusion Criteria:

• Patients under legal protection
• Patients with concomitant pulmonary embolism
• Patient with proximal or distal deep vein thrombosis
• Patient treated with anticoagulant therapy for another indication
• Patient with a contraindication to anticoagulation: Thrombocytopenia less than 30,000 elements/mm3, active bleeding or history of severe bleeding.
• Patient opposed to participation in research

Patient with active cancer:

• Cancer treatment within the last 6 months,
• Detectable tumor disease, cancer treatment within the last 6 months, ongoing hormone therapy for cancer, palliative cancer.
• The patient has received potentially non-curative cancer treatment (notably palliative chemotherapy).
• Progression shows that the cancer treatment was not curative (due to recurrence or progression under treatment) (particularly in the case of recurrence after surgery)