Therefore at the current time, the clinical practice of VTE prophylaxis in thoracic surgery includes administration of unfractionated or low molecular weight heparin starting at the perioperative period and finishing at the time of patients' discharge. Prolonged thromboprophylaxis in orthopaedic surgery beyond 10 days and up to 35 days has become the standard of care and has Grade 1A recommendations from ACCP. This approach has never been tested or validated in thoracic surgery, where major lung resection exposes the patient to an increased VTE risk not only due to the surgical stress and existence of malignancy, but also due to direct in-situ vascular injury secondary to resection of pulmonary arterial branches during the lung resection. Hence, there is a clear need to systematically evaluate the incidence of VTE after resection of lung malignancies and to evaluate the role of extended VTE prophylaxis in preventing DVT and pulmonary embolus (PE) after those major lung resections.