VTE: Up to 10% with unexplained embolus will have cancer
In patients with unprovoked venous thromboembolism, what is the likelihood that they will also have an undiagnosed cancer?
Approximately 1 in 17 patients with a venous thromboembolism (VTE) not immediately relatable to a specific cause will have cancer diagnosed at the time of the episode. One in 10 patients will have cancer diagnosed within 1 year. The authors argue that all episodes of unprovoked VTE should be accompanied with extensive screening to identify cancer. (LOE = 1a)
Carrier M, Le Gal G, Wells PS, Fergusson D, Ramsay T, Rodger MA. Systematic review: The Trousseau Syndrome revisited: Should we screen extensively for cancer in patients with venous thromboembolism? Ann Intern Med 2008;149(5):323-333. [PMID:18765702]
The researchers conducting this study searched 4 databases, including the Cochrane trials registry, and hand searched conference proceedings to identify observational or randomized trials that reported the incidence or prevalence of previously undiagnosed cancer following a VTE. They included studies in any language and reviewed reference lists of retrieved articles to find other studies. Two researchers independently selected the articles and abstracted the data. Thirty-six studies reported on a total of 9516 patients with VTE. Of these patients, 35% had unprovoked VTE, the definition of "unprovoked" as defined by the original researchers. A total of 6.1% of patients with unprovoked VTE had cancer identified within 1 month of the episode (95% CI, 5.0% - 7.1%). Ten percent of patients with unprovoked VTE had cancer diagnosed within 1 year (8.6% - 11.3%). Half the cases of cancer were found using limited screening at the time of the embolus; that is, history and physical, blood testing, and chest radiography. Extensive screening identified 70% of the cancers; tomography of the abdomen was best test. The researchers argue that extensive screening should be performed in patients with unprovoked VTE, reasoning that earlier detection could lead to better outcomes if cancer-related VTE is treated differently than idiopathic VTE.
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