Cause of Death among Patients with Local or Regional Stage Cancer of the Breast, Colon and Lung Who Develop Venous Thromboembolism (VTE).

Background: Previous data has shown that cancer-related VTE is associated with reduced two-year survival for patients with several tumor types. The reason for the survival difference is not clear.

Methods: Using the California cancer registry and hospital discharge data, we identified all cases diagnosed with colon, breast and lung cancer over a 6-year period. Patients with local or regional stage cancer who developed incident VTE within 2 years after the diagnosis of cancer were identified. The cause of death was determined using a master death registry. Each VTE case was compared to 4 case-controls without VTE after matching for age, race, sex, stage and number of medical co-morbidities. The odds ratio (OR) for dying from any cause and dying due to the underlying cancer in the subsequent 2 years was calculated.

Results (Table): Approximately 40% of all deaths occurred < 30 days of the VTE diagnosis for all cancers. The longer the time interval between cancer diagnosis and VTE, the greater the relative risk of dying of cancer.

Conclusions: Patients with lung, breast and colon cancer who developed VTE < 2 years after cancer diagnosis were significantly more likely to die, and death was attributed to the underlying cancer in a sizable percentage of these cases. This indicates that among patients initially diagnosed with local or regional stage cancer of the breast, colon or lung, VTE is frequently a harbinger or consequence of metastatic stage.