Effects of the Timing of Venous Thromboembolic Events on Survival of Patients with Uterine Cancer

Background: Cancer patients are at high risk for venous thromboembolic event (VTE), and the occurrence of VTE can affect the prognosis. However, it is unclear if the timing of VTE can influence the prognosis. The purpose of this study was to evaluate the incidence and impact of the timing of VTE (early vs late) on the survival of patients with uterine cancers.

Methods: A retrospective cohort study was conducted. The study population included all uterine cancer patients who had newly diagnosed episode of VTE from January 1^st 2006 to December 31^st2007 at MD Anderson Cancer Center. Medical records of these patients were reviewed for cancer diagnosis, patient demographics, metastasis, date of diagnosis of VTE, type of VTE, the site of VTE, and any recurrences during the follow up period of 2 years since the first VTE. Clinical and laboratory parameters predictive for survival were also reviewed. All VTE episodes, including symptomatic as well as incidental VTEs were confirmed by the radiological studies using CT ANGIO, CT scan, Doppler compression ultrasound or V/Q perfusion scans. The survival time was defined as the time from the date of cancer diagnosis to the date of death, or to the date of last follow up. Survival analysis was conducted using Kaplan-Meier method and Cox proportional hazard models.

Results: Of the 2151 patients with newly diagnosed VTEs within the 2 years study period, 33 patients were found to have uterine cancers. The median age was 60 years (range 41-84 years). Among all the primary VTEs, 42% were pulmonary embolus (PE); 45% were deep vein thrombosis (DVT), and 12% were concurrent PE/DVT (diagnosed on the same day). The median time of VTE from the date of cancer diagnosis was 8 months (range 0 - 88 months). The majority of these VTE events (55%) were found to occur within 1 year from the date of cancer diagnosis. A total of 8 patients had 10 recurrent episodes of VTE (2 patients had 2 recurrent VTE episodes) during the follow up period. The median survival time was 33 months (range 2.6-121.6 months); 82% of these patients had a metastatic disease. Multivariate proportional hazards model showed that the diagnosis of VTE within 6 months from the cancer diagnosis [Hazard ratio: 3.8, 95% CI (1.1-12.9), p=0.03] and the presence of baseline white blood cell (WBC) count of greater than 11,000/uL [Hazard ratio: 3.5, 95% CI (1.0-12.2), p=0.045] were statistically significant independent predictors for 2 year survival adjusting for age, presence of central venous catheter (CVC), and the baseline platelet count of greater than 350,000/uL.

Conclusion: These findings suggest that the timing of VTE is an important indicator of prognosis in patients with uterine cancer; patients who had VTE within 6 months from cancer diagnosis had a shorter 2 year survival. Future larger studies may better define the impact of timing of VTE on survival of patients with Uterine Cancers.