Revisiting Prevention of Blood Clots in Chemotherapy Patients

A new study just published online in The Oncologist shows that outpatients receiving chemotherapy are at high risk of developing venous thromboembolism (VTE) and of major bleeding complications, especially those with pancreas, stomach and lung cancer. The authors therefore conclude that thromboprophylaxis, or blood thinning treatments, should be considered for such patients, after carefully assessing the risks and benefits of treatment.

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...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.

Durham, NC (PRWEB) November 08, 2013

A large-scale analysis assessing the real-world risk of venous thromboembolism (VTE), commonly called blood clots, among chemotherapy patients shows a greater occurrence of VTE than identified in clinical trials, with a progressively increased risk during the year following treatment initiation. The study shows that 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 therefore conclude that thromboprophylaxis, or blood thinning treatments, should be considered for such patients, after carefully assessing the risks and benefits of treatment.

The study, led by Gary H. Lyman, MD, at the Duke University School of Medicine and Duke Cancer Institute, in collaboration with scientists from Sanofi and King’s College Hospital in London, UK was published online this week in The Oncologist. The team of researchers hypothesized that 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, which recent studies have found to be safe and effective for use in the prevention of VTE in chemotherapy patients.

The study involved a random sample of approximately 27,500 patients with high-VTE-risk cancer types (i.e., lung, pancreas, stomach, colon/rectum, bladder or ovary) who had undergone chemotherapy. The group retrospectively evaluated the patients’ VTE risk as well as their risk of bleeding and the economic burden borne by the patient 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 3 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, and the overall incidence of the complication was 13.5% 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%, compared with 9.6% in patients without VTE. These rates are higher than has been reported with anticoagulation use in clinical trials, again likely reflecting how clinical claims data can be more representative of actual practice than clinical trial data. Moreover, while the baseline healthcare costs of patients who would develop VTE were comparable to those of patients who would not, 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.

The authors discussed the fact that the incidence of VTE reported in this study is inconsistent with those previously reported for placebo groups in randomized clinical trials, which may be due to the selection of lower-risk patients for participation in these studies. “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,” said Dr. Lyman, head researcher of the study and co-chair of the recently published American Society of Clinical Oncology Guideline’s on VTE Treatment and Prevention. He added, “[The] risk continues to increase over time during the year following initial treatment.” This observation highlights the importance of using an unselected population to evaluate the true risk of a disease.

According to Dr. Lyman, “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.”

Lecia V. Sequist, MD, Deputy Editor of The Oncologist adds, “This report illustrates the frequency, complications and costs of blood clots in everyday clinical practice. While prophylactic anticoagulation during chemotherapy is not currently recommended, the authors demonstrate inherent shortcomings in studying selected patients on clinical trials. Ideally, future studies on this issue will be able to better approximate the real world, and most importantly identify the patients at highest risk for subsequent VTE.”

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The full article, titled “Venous Thromboembolism Risk in Patients with Cancer Receiving Chemotherapy: A Real-World Analysis,” can be accessed at http://www.TheOncologist.com.

About The Oncologist
Established by oncologists to help physicians better manage their practices in an ever-changing environment, The Oncologist® is the official journal of the Society for Translational Oncology (STO). Now in its 18th year, this internationally peer-reviewed journal focuses on clear and concise interpretation addressing the multimodality diagnosis, treatment, and quality of life of the cancer patient. Each issue is meant to impact the practice of oncology and to facilitate significant communication in the introduction of new medical treatments and technologies. For more information, visit http://www.TheOncologist.com.

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Article: TE Risk in Cancer Patients Receiving Chemotherapy