Purpose Venous thromboembolism (VTE) is common in cancer patients. Evidence has suggested that low molecular weight heparin (LMWH) might improve survival in patients with cancer by preventing both VTE and the progression of metastases. No trial in a single cancer type has been powered to demonstrate a clinically significant survival difference. The aim of this trial was to investigate this question in patients with lung cancer. Patients and Methods We conducted a multicenter, open-label, randomized trial to evaluate the addition of a primary prophylactic dose of LMWH for 24 weeks to standard treatment in patients with newly diagnosed lung cancer of any stage and histology. The primary outcome was 1-year survival. Secondary outcomes included metastasis-free survival, VTE-free survival, toxicity, and quality of life. Results For this trial, 2,202 patients were randomly assigned to the two treatment arms over 4 years. The trial did not reach its intended number of events for the primary analysis (2,047 deaths), and data were analyzed after 2,013 deaths after discussion with the independent data monitoring committee. There was no evidence of a difference in overall or metastasis-free survival between the two arms (hazard ratio [HR], 1.01; 95% CI, 0.93 to 1.10; P = .814; and HR, 0.99; 95% CI, 0.91 to 1.08; P = .864, respectively). There was a reduction in the risk of VTE from 9.7% to 5.5% (HR, 0.57; 95% CI, 0.42 to 0.79; P = .001) in the LMWH arm and no difference in major bleeding events but evidence of an increase in the composite of major and clinically relevant nonmajor bleeding in the LMWH arm. Conclusion LMWH did not improve overall survival in the patients with lung cancer in this trial. A significant reduction in VTE is associated with an increase in clinically relevant nonmajor bleeding. Strategies to target those at greatest risk of VTE are warranted.

Objectives: Chemotherapy increases the risk of thromboembolism in patients with cancer. Although thrombocytopenia is a known side effect of chemotherapy, reactive thrombocytosis related to chemotherapy is uncommonly reported. The present study aimed to determine the incidence of gemcitabine-related thrombocytosis and the associated risk of thromboembolism. Methods: Medical records of 250 consecutive patients with a malignant disease who received gemcitabine-based therapy were reviewed. A multivariate analysis was done to determine factors associated with thromboembolism. Results: A total of 220 eligible patients with a median age of 63 years (range 26–83) were identified. Of these 220 patients, 95% had advanced malignancy and 59% had received prior chemotherapy. A total of 69% of patients received a platinum combination. In all, 46% patients experienced thrombocytosis following chemotherapy, with a median platelet count of 632 × 10⁹/l (range 457–1,385). Twenty-three of the 220 patients experienced a vascular event within 6 weeks of treatment. Eleven patients with thrombocytosis experienced a vascular event compared with 10 patients without thrombocytosis (not significant). On multivariate analysis, leukocytosis (odds ratio 5.8, 95% confidence interval 2.1–15.8) and comorbid illnesses (odds ratio 4.1, 95% confidence interval 1.4–12.6) were correlated with thromboembolism. Conclusions: Although gemcitabine-based therapy has been associated with an increased incidence of thrombocytosis, it does not increase the risk of thromboembolism in cancer patients. Leukocytosis and comorbid illnesses do increase the risk of thromboembolism.