A 53-year-old man comes to the office due to a 3-day history of right leg swelling and pain. He has had no chest pain or dyspnea. The patient describes himself as healthy, and his last visit to the doctor was 10 years ago. He has had no weight loss or abdominal pain. The patient smokes and has a 30-pack-year history. He has an active lifestyle and has not recently traveled. The patient's mother died of breast cancer, and his father has congestive heart failure. Temperature is 37 C (98.6 F), blood pressure is 140/80 mm Hg, pulse is 70/min, and respirations are 14/min. Oxygen saturation is 97% on room air. Normal vesicular breath sounds and cardiac sounds are heard on chest auscultation. Abdominal examination is unremarkable. The right leg is swollen and tender up to midthigh. Results of complete blood cell count and coagulation studies are within normal limits. Duplex ultrasonography demonstrates incompressible popliteal and femoral veins, and anticoagulation is started immediately. Chest x-ray is unremarkable. Which of the following is most appropriate in evaluation of this patient's current condition?
This patient has deep venous thrombosis (DVT) of the popliteal and femoral veins. Risk factors for venous thromboembolism (VTE) include inherited (eg, factor V Leiden, prothrombin gene mutation, protein C deficiency) and acquired (eg, immobilization, surgery, malignancy, medications) factors. Initial evaluation is directed at identifying major causes of VTE or factors that can increase the risks of anticoagulation therapy; evaluation should include careful history, physical examination, and limited diagnostic testing (eg, blood counts, serum chemistries, coagulation studies, fecal occult blood testing, chest x-ray).
In the absence of any clear provoking factors (eg, recent surgery, immobilization), patients with a first episode of VTE, such as this man, should be referred for age-appropriate cancer screening (eg, colonoscopy) to evaluate for malignancy as a potential risk factor for VTE. In addition, any suspicious symptoms of malignancy (eg, weight loss, unexplained pain) warrant consideration for more extensive cancer evaluation (eg, CT scan of the abdomen) (Choice B).
(Choice C) Because of this patient's smoking history, he should be offered screening for lung cancer with low-dose CT scan of the chest. However, he has a normal chest x-ray and no symptoms concerning for lung cancer (eg, hemoptysis, cough), so positron emission tomography of the chest would not be appropriate.
(Choice D) Testing for an inherited thrombophilia (eg, factor V Leiden; deficiency of protein C, protein S, or antithrombin III) is generally considered only if the patient's history is suggestive of a genetic predisposition (eg, recurrent VTE; multiple or unusual sites of thrombosis; family history of VTE, particularly at a young age).
(Choice E) Carbohydrate antigen (CA) 19-9 and carcinoembryonic antigen are tumor markers generally used to trend disease progression in patients with diagnosed pancreatic and gastrointestinal tract cancer, respectively. They are not effective screening tests.
Educational objective:
In the absence of any clear provoking factors (eg, recent surgery, immobilization), patients with a first episode of venous thromboembolism should be referred for age-appropriate cancer screening (eg, colonoscopy) to evaluate for malignancy as a potential risk factor for this disease.