Residual Vein Thrombosis Improves Screening for Occult Cancer: Results On 537 Patients with Idiopathic Deep Vein Thrombosis

Background: Clinical advantage of extensive screening for occult cancer in patients with idiopathic Deep Vein Thrombosis (DVT) is unknown. We have demonstrated that the Residual Vein Thrombosis (RVT)-based screening for occult cancer improves early detection as well as cancer-related mortality (Siragusa S et al. Blood 2007;110(699):OC). Here we report on final analysis of 537 patients over a period of 8 years. Objective of the study: We conducted a prospective study evaluating whether a RVT-based screening for cancer is sensitive and influences cancer-related mortality. Study design: Prospective with two cohorts of DVT patients: the first cohort was monitored for clinical overt cancer only (Group A), while the second (Group B) received complete screening for occult neoplasm and subsequent surveillance. Materials and methods: Consecutive patients with a first episode of DVT who presented RVT after 3 month of anticoagulation and without signs and/or symptoms for overt cancer. Screening for occult cancer was based on: ultrasound and/or CT scan of the abdomen and pelvis, gastroscopy, colonoscopy or sigmoidoscopy, hemoccult, sputum cytology and tumor markers. These tests were extended with mammography and Pap smear for women and ultrasound of the prostate and total specific prostatic antigen (PSA) for men. All investigations had to be completed within four-weeks from the assessment of RVT. All patients were followed-up for at least 2 years. Incidence and cancer-related mortality was compared between the two groups by survival curves (Kaplan-Mayer) and related Breslow test for statistics. Results: Over a period of 8 years, 537 patients were included in the analysis: first cohort included 346 patients (Group A), second cohort 191 (Group B). Clinical characteristics between groups were homogenous. During the follow-up, 8.3% of patients developed overt cancer in group A; in group B, 7.8% of patients had diagnosed cancer at the moment of extensive screening while 2 new cases (0.7%) occurred during the follow-up (Table). The sensitivity of this approach was 92.1% (95% confidence intervals 75.2-104.2). Cancer-related mortality was 7.5% in group A and 3.6% in group B (p< 0.001). Conclusions: The RVT-based screening for occult cancer is highly effective for improving early detection as well as cancer-related mortality in a cohort of 537 patient with DVT of the lower limbs.