Increased Prevalence but Reduced Mortality of Venous Thromboembolism After Major Cancer Surgery
In a study reported in JAMA Surgery, Vincent Q. Trinh, BSc, of the University of Montreal Health Centre, and colleagues assessed trends in incidence and mortality of venous thromboembolism after major cancer surgery in the United States between 1999 and 2009. They found that venous thromboembolism rates have increased and that venous thromboembolism mortality rates have decreased over this period. Overall, venous thromboembolism was associated with a 5.3-fold increased risk of death. Factors associated with increased risk of venous thromboembolism included older age, female sex, Medicare insurance, and Medicaid insurance and urban location, teaching status, and Northeast region for hospitals.
Study Details
In the study, patients undergoing colectomy, cystectomy, esophagectomy, gastrectomy, hysterectomy, lung resection, pancreatectomy, or prostatectomy for cancer were identified retrospectively from the Nationwide Inpatient Sample for between January 1999 and December 2009. Venous thromboembolism following surgery was assessed according to date, patient, and hospital characteristics, and determinants of in-hospital venous thromboembolism were investigated using logistic regression analysis.
Venous Thromboembolism and Mortality Rates
Among a weighted estimate of 2,508,916 patients undergoing major cancer surgery, in-hospital venous thromboembolism after surgery occurred in 33,409 patients (1.3%). The estimated annual prevalence of venous thromboembolism increased by 4.0% (P < .001), whereas mortality from venous thromboembolism exhibited a decline in estimated annual prevalence of 2.4% (P = .03). Over the same period, mortality after major surgery also exhibited a 2.4% decline in annual prevalence (P < .001).
Factors in Venous Thromboembolism Risk
In multivariate logistic regression analysis adjusting for year of surgery, age, race, baseline Charlson comorbidity index, median zip code household income, hospital location, hospital region, and hospital teaching status, factors associated with significantly increased risk of venous thromboembolism were older age (odds ratio [OR] = 1.03, P < .001), female sex (OR = 1.25, P < .001), black race (OR = 1.56, P < .001, vs white), Charlson comorbidity index score of 3 or more (OR = 1.85, P < .001), and Medicaid insurance (OR = 2.04, P < .001), Medicare insurance (OR = 1.39, P < .001), and no insurance (OR = 1.49, P < .001; all vs private insurance). Nonwhite and nonblack race was associated with reduced risk of venous thromboembolism (OR = 0.75, P < .001).
Treatment in urban hospitals (OR = 1.32, P < .001) and teaching hospitals (OR = 1.08, P = .01) was associated with significantly increased risk of venous thromboembolism and treatment in hospitals in the Midwest (OR = 0.90, P = .01), South (OR = 0.89, P = .001), and West (OR = 0.88, P = .001) was associated with significantly reduced risk compared with hospitals in the Northeast. There were no differences in risk according to hospital volume.
Mortality Rates
Overall, mortality after major cancer surgery was 2.0%, with rates of 7.2% after esophagectomy, 5.7% after gastrectomy, 4.9% after pancreatectomy, 3.1% after colectomy, 2.9% after lung resection, 2.5% after cystectomy, 0.4% after hysterectomy, and 0.1% after prostatectomy.
On multivariate analysis, patients with vs without venous thromboembolism had a 5.3-fold greater risk of mortality overall (12.0% vs 1.9%, OR = 5.30, P < .001) and a significantly increased risk after every evaluated procedure, with odds ratios of 3.74 for colectomy (11.3% vs 2.9%, P < .001), 4.58 for cystectomy (9.6% vs 2.3%, P < .001), 2.01 for esophagectomy (13.6% vs 6.9%, P = .02), 2.81 for gastrectomy (14.7% vs 5.5%, P < .001), 10.93 for hysterectomy (5.2% vs 0.3%, P < .001), 8.73 for lung resection (19.8% vs 2.6%, P < .001), 3.08 for pancreatectomy (13.2% vs 4.7%, P < .001), and 56.42 for prostatectomy (3.9% vs 0.1%, P < .001).
The investigators concluded, “During our study period, [venous thromboembolism] events following major cancer surgery increased in frequency; however, associated [venous thromboembolism] mortality decreased. Changing [venous thromboembolism] detection guidelines and better management of this condition may explain our findings.”
The study was supported by the University of Montreal Health Centre Urology Specialists, Fonds de la Recherche en Santé du Québec, the University of Montreal Department of Surgery, and the University of Montreal Health Centre Foundation.
Quoc-Dien Trinh, MD, of Dana-Farber Cancer Institute and Harvard Medical School is the corresponding author for the JAMA Surgery article.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
