The purpose was to determine the incidence and prevalence of venous thromboembolism (VTE) in acute leukemia patients from our institution. We conducted a retrospective study on newly diagnosed acute leukemia patients who presented at our institution from November 1999 to May 2005. Descriptive statistics and cross-tabulation were used to describe patient characteristics. Measures of morbidity were used to address VTE risk. Chi-square testing, Fisher's exact testing, Mann–Whitney analyses, or median testing were used to determine between-group differences. Data analyses were conducted using Stata version 11 (Stata Corp., College Station, TX). Two hundred and ninety-nine patients with acute lymphoblastic leukemia (ALL) and 996 patients with acute myeloid leukemia (AML) were included. After excluding patients diagnosed with VTE prior to or at the time of leukemia diagnosis, during the mean time follow-up period of 2.5 years (range: 0.0025–10.3 years), the overall incidence rate of VTE was 3.7 per 100 person-years: 4.2 per 100 person-years for ALL and 3.4 per 100 person-years for AML. Among all patients, the majority (80.6%) developed VTE within 12 months after diagnosis and during thrombocytopenia. The most common VTE was central venous catheter (CVC)-associated upper-extremity deep venous thrombosis. Pulmonary embolism occurred in 15% of ALL patients and 8% of AML patients. VTE recurred in 20.7% of ALL patients and 18.6% of AML patients. VTE occurs frequently in patients with acute leukemia. Studies are needed to identify risk factors for the development and recurrence of VTE among patients with acute leukemia and to establish more effective methods for preventing and treating VTEs in leukemia patients who have thrombocytopenia and/or CVC.

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It has been reported that cancer increases the risk of VTE 4-6-fold. The incidence of VTE in cancer pts has been estimated at 1 in 200 per year and has been well documented in solid tumors. Far less is known about the incidence of VTE in pts with hematological malignancies although a recent publication (Blom et al, JAMA293:715, 2005) suggested that pts with hematological malignancies such as lymphoma and multiple myeloma may be at a higher risk of developing VTE than pts with solid tumors. The incidence and risk of VTE has not been well studied in acute leukemias, a population in which prophylaxis is underutilized given the thrombocytopenia associated with intensive chemotherapy. To evaluate the incidence of VTE in pts with hematological malignancies further and to assess the need for VTE prophylaxis, we conducted a retrospective chart review of 299 pts with ALL, BL, or LL who were seen at M.D. Anderson Cancer Center Center from November 1999 to May 2005. Pts received a hyper-CVAD based regimen (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone alternating with methotrexate and high-dose cytarabine). The median observation period was 188 weeks (range 1–328 wks) and included post-consolidation chemotherapy, allogeneic stem cell transplant, and/or salvage chemotherapy. Among 298 evaluable pts, 52 (17%) had confirmed VTE by imaging studies. In 7 pts, VTE was the presenting sign of the malignancy. The median age of pts who developed VTE was significantly higher than of those who did not develop VTE, 48.5 yrs (range 19–75) vs. 42 yrs (range 15–83), respectively (p=0.04). With each year increase in age, the risk of having VTE increased approximately by 1.7% (p=0.059). ALL pts with Philadelphia chromosome (Ph) had a higher incidence of VTE than all other pts (p=0.02), and were 1.8 times more likely to have VTE than non-Ph ALL pts (p=0.007). Caucasian pts or those with history of prior VTE had a significantly higher incidence of VTE (p=0.03 and p=0.002, respectively). The risk was 2 fold higher for Caucasians and 12 fold higher for those with a prior history of VTE. At the time of VTE, platelet counts were below 50 x 109/L in 33%, 50–100 x 109/L in 10%, and greater than 100 x 109/L in 57%. VTE occurs in a significant proportion of pts with ALL, BL, and LL. Thrombocytopenia does not preclude the development of VTE. Older age, Ph positivity, race, and history of prior VTE were significantly associated with the development of VTE. Further analysis of other known risk factors such as the use of erythropoiesis-stimulating agents, hormonal therapy, and other comorbidities is underway to better refine the subpopulation at risk.

Background: Pts with cancer are at increased risk of thromboembolic events with potentially life-threatening consequences. The incidence of VTE in cancer pts has been estimated at 1 in 250. Although most of these episodes are associated with solid tumors, VTE is also observed in pts with acute leukemias, even in the presence of thrombocytopenia. Anticoagulation in this pt population can be particularly problematic if pts are undergoing myelosuppressive chemotherapy. VTE prophylaxis is often not given because of the perceived high risk of bleeding with a presumed low risk of VTE. Method: As little is known about the incidence and significance of VTE in pts with acute leukemia, we conducted a retrospective chart review of 223 pts with ALL, BL, or LL who received a hyper-CVAD regimen (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone alternating with methotrexate and cytarabine) with or without rituximab, maintenance chemotherapy (with L-asparaginase only months #7 & 18), allogeneic stem cell transplant (SCT), or salvage chemotherapy at our institution from November 1999 to May 2005. The median observation period was 112 weeks (range 1–328). Results: The median age was 51 yrs (range 19–75). 70% were ALL, (50% were Philadelphia positive ALL), 20% Burkitt’s or Burkitt’s-like, and 10% LL. Thirty nine of 223 pts (18%) had confirmed VTE by imaging studies: 12.5% prior to or at the time of diagnosis, 57.5% during consolidation chemotherapy, and 27.5% during maintenance chemotherapy, SCT, or supportive care. Location of VTE varied by site: 3/39 (8%) pulmonary embolus, 16/39 (41%) lower extremity, 2/39 (5%) central venous catheter (CVC), and 18/39 (46%) upper extremity. Two of the 18 with upper extremity VTEs did not have CVC, and an additional 2 had bilateral upper extremity thromboses. The platelet counts were reviewed near the time of VTE diagnosis: 22/39 (56%) had greater than 100 × 109/L, 17/39 (44%) were less than that value, with 76% below 50,000 × 109/L. Conclusion: Pts with ALL, BL, and LL undergoing therapy are at risk for developing VTE. Thrombocytopenia does not preclude development of VTE. A more detailed analysis will be forthcoming regarding the risk factors for VTE in this pt population, the current medical practices and bleeding complications with VTE prophylaxis and treatment, and the effect on therapy administration and overall survival. Practice guidelines for management of acute leukemia pts with thromboembolic events should be pursued.