A literature review shows that previously undiagnosed cancer will be detected within 12 months in one in ten patients with a sudden-onset, unprovoked venous thromboembolism (VTE).
Dr. Marc Carrier at the University of Ottawa, Canada, and colleagues reviewed abstracts of observational or randomized controlled trials from a number of large databases to determine the prevalence or incidence of previously undiagnosed cancer after VTE.
They found 36 studies of VTE that documented a first diagnosed cancer within 12 months of VTE.
The prevalence of previously undiagnosed cancer in patients with unprovoked VTE was 6.1 per cent at baseline and 10.0 per cent at 12 months.
"One in ten patients will eventually be diagnosed with cancer in the 12 months following the DVT/PE," Dr. Carrier commented to Reuters Health. "Only approximately two-thirds of patients will be diagnosed at baseline. Therefore, ongoing surveillance is important."
An extensive screening strategy "using computed tomography of the abdomen and pelvis statistically significantly increased the proportion of previously undiagnosed cancer from 49.4 per cent (with limited screening alone) to 69.7 per cent in patients with unprovoked VTE," Dr. Carrier and colleagues report in the September 2 issue of the Annals of Internal Medicine.
In an accompanying editorial, Dr. Deborah L. Ornstein of Yale University in New Haven, Connecticut, writes, "If we look hard enough, we can find hidden cancer in a sizable proportion of patients with idiopathic VTE."
Whether or not extensive screening is cost-effective is unknown, however. "The search can cost thousands of dollars, and we still may not find the cancer," Dr. Ornstein says. "Even if we do find it, we still don't know whether we can improve cancer-related survival in these patients."
"All patients should have a complete medical history and physical examination, basic blood work (including complete blood count, liver function tests, renal function tests and calcium) and a chest X ray," Dr. Carrier advised.
"Physicians should make sure that their patients are up-to-date regarding breast, cervical and prostate cancer screening, according to guidelines. Any abnormalities on the above tests should be investigated as appropriate. It is still unclear if any other or more extensive tests should be performed for all patients with unprovoked DVT/PE," he continued.
"Decisions should be made on an individual basis after assessing the patient. If further tests are warranted, then computed tomography of the abdomen and pelvis gives you the best yield."
Dr. Carrier echoed Dr. Ornstein's concerns. "Although CT of the abdomen and pelvis finds more cancers, it is unknown if this will lead to a better cancer outcome, with a decrease in mortality or morbidity for your patient."
Ann Intern Med 2008;149:323-333, 350-352
