Deep Venous Thrombosis in Patients with Lung Cancer: Patterns and Predictors of Thrombosis and Prognostic Implications.

Deep venous thrombosis (DVT) is a relatively common complication in patients with cancer. The occurrence of DVT may a play a role in the over all prognosis of these patients. We retrospectively reviewed a cohort of 276 patients with lung cancer of various histologies with regards to demographics, types of thrombosis and survival. These patients were followed in our clinic from 1997 to 2004. Median age of patients was 62 and the male to female ratio was 1.59 to 1. Small cell lung cancer (SCLC) was the histology among 39 patients (14 %) and non small cell lung cancer (NSCLC) among the remaining 237 patients (86 %). Among NSCLC, the distribution of various sub types was: 95(34 %) adenocarcinoma, 64(23 %) squamous cell, 5 (1%) large cells and 73(26%) non-small cell, not other wise specified. Metastatic disease was present in 28 % (67/237) of NSCLC and 51% (20/39) of SCLC patients. Most (83%) had an excellent performance status of 0 or 1 and only 27% had weight loss at the initial time of diagnosis. Among 276 patients, 44 (16 %) had DVT. Of these, 7 patients had DVT prior to the diagnosis of lung cancer. The remaining 37 (85 %) had DVT during the course of their lung cancer. Among patients with thrombosis, 17 patients (39 %) developed pulmonary thromboembolism (PTE). The incidence of thrombosis in SCLC (13 %) was not statistically different from NSCLC (16 %). However there was increased incidence of thrombosis among patients with adenocarcinoma or when histology was only characterized as non small cell, not other wise specified; 20% (34/168) compared to 9 % (10/108) among all other histological subtypes (P= 0.015). Among patients with metastatic disease, 18% (16/87) had DVT compared to 15% (28/189) in those with early stage disease (P= 0.451). The median survival (MS) of patients with SCLC and DVT was 10 months compared to those without DVT and SCLC of 16 months (P = 0.4135). The MS of patients with NSCLC and DVT was 16 months compared those without DVT and NSCLC of 21 months (P = 0.1262). There is only limited literature specifically looking at various factors affecting the incidence of and the prognostic value of DVT in patients with lung cancer. We found in this study that the incidence of DVT among lung cancer patients was 16 %. The incidence of DVT among lung cancer patients when histology was adenocarcinoma or when histology was only characterized as non small cell, not other wise specified was twice compared to other histologic sub types. In those who develop DVT associated with lung cancer, a very high proportion (39 %) developed PTE. Even with anticoagulation, the overall survival of those patients who developed DVT was shorter than those who did not develop DVT but the difference did not reach statistical significance. Most of our patients with lung cancer and DVT were treated with low molecular weight heparin and whether this aggressive anticoagulant approach provided additional anti neoplastic benefit is debatable. Currently there are therapeutic trials looking at the role of prophylactic use of low molecular weight heparins as a means to enhance the survival in patients with lung cancer.