Frequency, Clinical Pattern and Outcome of Thrombosis in Cancer Patients in Saudi Arabia

Objectives: Thrombotic risk is increased in patients with cancer and there are important implications for those who suffer a venous thromboembolism (VTE). We undertook this study to determine the frequency, clinical patterns, and outcome of VTE in Saudi patients with cancer. Methods: Cancer (solid tumors and lymphoma) patients who developed VTE from January 2004 to January 2009 were studied retrospectively. Demographics and clinical characteristics related to thrombosis and cancer were evaluated. Results: A total of 701 patients with cancer were seen during the study period. VTE was diagnosed in 47 (6.7%) patients (median age 52, range 18-80 years). Lower limb DVT was the most common type, seen in 47% patients, followed by PE in 19%, and 19% patients had both DVT & PE. Thrombosis was symptomatic in 72% patients while it was an incidental finding on routine workup in 28%. Cancer and VTE were diagnosed at the same time in 38% of patients, and 47% patients developed VTE during the course of disease after the cancer diagnosis. The majority of VTE post cancer diagnoses occurred during the first year (median 4 months, range 1-14). Additional risk factors for VTE were present in 22 (47%) patients and 14 (30%) of these patients were receiving chemotherapy at the time of thrombosis. Only 5 (10.6%) patients were receiving thrombo-prophylaxis at the time of VTE diagnosis. Most common types of tumors associated with thrombosis were breast cancer, non-Hodgkin's lymphoma and lung cancer. The majority of the affected patients (79%) had advanced stage of cancer. After a median follow-up of 13 (range 0.5-60) months, 38 (81%) patients had died. There was no difference in the mortality of patients with symptomatic or asymptomatic thrombosis (82% vs 78.6%). Conclusions: Thrombotic complications can develop in a significant number of patients with cancer, and almost half of the patients have additional risk factors for VTE. Thrombosis is usually associated with advanced disease and can be asymptomatic in more than a quarter of cases. Thromboprophylaxis in cancer patients is under-utilized. Community based studies are needed to accurately define the extent of this problem and to develop effective prophylactic strategies.