Heparin use and venous thromboembolism (VTE) among cancer patients receiving chemotherapy with a prior history of VTE

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Background: Heparin is an effective treatment option for the prevention of venous thromboembolism (VTE) in cancer patients on chemotherapy. To date, information on the use of both low molecular weight heparin (LMWH) and non-LMWH in cancer patients receiving chemotherapy that have had a prior VTE is lacking. We evaluated heparin treatment patterns as well as the incidence of VTE in a cohort of cancer patients receiving chemotherapy, who have had a VTE prior to their cancer diagnosis. Methods: We conducted a retrospective cohort study using a large claims database representing the U.S. commercially-insured population. The cohort included all patients 18–64 years old from 2000 to 2007 who were diagnosed with cancer, were on chemotherapy, and who had a VTE occurring up to 12 months before cancer (n=331). We defined a diagnosis of cancer as two ICD-9 claims 30 days apart or more. A combination of ICD-9, HCPCS, and CPT codes were used to capture chemotherapy treatment after cancer. A VTE was identified by a single ICD-9 claim of 415.1, 451.2, 451.81, 451.9, 453.1, 453.2, 453.8, or 453.9. VTE claims occurring within 6 months of the index claim were considered part of the same VTE event. A patient was considered to have a VTE after cancer if they had a VTE claim that occurred both after the cancer diagnosis and at least 6 months beyond the most recent pre-cancer index VTE date. Results: Fifty-one percent of cancer patients with a history of VTE were prescribed an anticoagulant (n = 171). Fewer patients took LMWH compared to non-LMWH (6.7% versus 27.8%) while a portion took both (17.2%). A VTE after cancer was experienced by 49.1% of those on any kind of anticoagulant, 45.4% of those taking LMWH, 43.5% of those taking non-LMWH, and 59.6% of those who had taken both types. Fewer VTEs were reported among those taking no anticoagulants (29.4%). Conclusions: Approximately half of all cancer patients receiving chemotherapy were receiving heparin, with a smaller proportion using only LMWH. Even with prophylaxis, VTE recurs in half of cancer patients with a VTE history who receive chemotherapy. Recurrent VTE is a serious risk despite heparin or LMWH prophylaxis.

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Prevalence of early-stage prostate and estrogen receptor positive (ER+) breast cancer patients receiving primary androgen deprivation therapy (ADT) and aromatase inhibitors (AIs) in the United States (U.S.)

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Background: AIs and ADT are used to prevent recurrence of breast and prostate cancers but have been shown to accelerate bone loss. We estimated the prevalence of early-stage ER+ breast and prostate cancer patients on hormone therapy in the U.S., as this is not well-described in the literature. Methods: Data from the Surveillance, Epidemiology, and End Results (SEER) Program, published literature, clinical practice, and a large claims database were used. We began with the American Cancer Society's estimated number of new breast and prostate cancer cases for the year 2008. We then assessed the number of patients with localized/regional disease and ER+ tumors and those receiving primary ADT (both chemical and surgical) or AI therapy by applying proportions from SEER, published literature, clinical practice, and the claims database. Using these incident case counts, we calculated the 5-year prevalence using appropriate cohort-specific survival rates to sum the number of new and surviving cases over a 5-year period. Results: The estimated 5-year prevalence of early-stage ER+ breast cancer for women aged ≥50 years in the U.S. was 607,411, of which 293,904 (48.4%) were on AI therapy based on the claims database. However, because this data source was limited to women aged <65 years, we also used estimates from clinical practice to capture AI use for women of all ages. Based on clinical practice, 402,637 (66.3%) to 460,156 (75.8%) of early-stage ER+ breast cancer patients were on AI therapy. For early-stage prostate cancer, the estimated 5-year prevalence for all ages was 1,024,238, of which 141,451 (13.8%) were on primary ADT. However, these figures may underestimate current usage of hormone therapies, as our data and the literature show increasing trends in ADT and AI use for early-stage disease. Conclusions: Based on a combination of population-based data and the published literature, approximately half of all early-stage ER+ breast cancer patients and a modest proportion of early-stage prostate cancer patients are on hormone therapy in the U.S.

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