February 3, 2014 — A large-scale analysis assessing the real-world risk of venous thromboembolism (VTE) in chemotherapy patients shows a greater occurrence of VTE than identified in clinical trials. Risk progressively increases during the year following treatment initiation, according to the report.
The study shows outpatients receiving chemotherapy are at high risk of developing VTE and of major bleeding complications, especially those with pancreas, stomach and lung cancer. The authors conclude thromboprophylaxis should be considered for such patients after carefully assessing risks and benefits.
The Oncologist published the study, which is led by Gary H. Lyman, M.D., Duke University School of Medicine and Duke Cancer Institute, in collaboration with scientists from Sanofi and King’s College Hospital in London, U.K. The team of researchers hypothesized there is a definable high-risk cohort of patients who would benefit from thromboprophylactic treatment for VTE, and that the scope of this risk warrants consideration for the use of prophylaxes such as low- and ultra-low-molecular-weight heparins.
The study involved a random sample of approximately 27,500 patients with high-VTE-risk cancer types, such as lung, pancreas, stomach, colon/rectum, bladder or ovary, who had undergone chemotherapy. The group retrospectively evaluated the patients’ VTE risk, risk of bleeding and economic as a result of the disease.
The risk of VTE increased over time, with a greater percentage of patients developing the complication at 12 months after initiation of chemotherapy than at three months; this held true across three definitions of VTE considered. According to definition A, the least conservative of the three, VTE was most frequently observed in cancers of the pancreas, lung and stomach. The overall incidence of the complication was 13.5 percent at a year, with no indication of plateau or tapering at that time point. Patients with VTE showed a higher risk of major bleeding events in the year following chemotherapy initiation. According to definition A, that risk was 19.8 percent, compared with 9.6 percent in patients without VTE. These rates are higher than has been reported with anticoagulation use in clinical trials. Baseline healthcare costs of patients who would develop VTE were comparable to those who would not, and the costs of the VTE patients soared over the year following chemotherapy initiation. On average, patients with VTE had $110,719 in expenses compared with $76,804 for patients without VTE, a difference primarily accounted for by VTE-related inpatient, outpatient and emergency room expenses.
“Importantly, this observational study suggests that the observed rates of symptomatic VTE in real-world practice are considerably greater than reported in patients eligible for randomized clinical trials,” Lyman said. “Clinical oncologists need to be aware of the increased risk of this serious complication of cancer and cancer treatment, and when the risk is sufficiently great and the balance of benefits and harms acceptable, oncologists should consider prophylactic anticoagulation.”
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