Screening for Occult Cancer in Patients With Unprovoked Venous Thromboembolism: A Systematic Review and Meta-analysis of Individual Patient Data.

BACKGROUND: Screening for cancer in patients with unprovoked venous thromboembolism (VTE) often is considered, but clinicians need precise data on cancer prevalence, risk factors, and the effect of different types of screening strategies.

PURPOSE: To estimate the prevalence of occult cancer in patients with unprovoked VTE, including in subgroups of different ages or those that have had different types of screening.

DATA SOURCES: MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials up to 19 January 2016.

STUDY SELECTION: Prospective studies evaluating cancer screening strategies in adults with unprovoked VTE that began enrolling patients after 1 January 2000 and had at least 12 months of follow-up.

DATA EXTRACTION: 2 investigators independently reviewed abstracts and full-text articles and independently assessed risk of bias.

DATA SYNTHESIS: 10 eligible studies were identified. Individual data were obtained for all 2316 patients. Mean age was 60 years; 58% of patients received extensive screening. The 12-month period prevalence of cancer after VTE diagnosis was 5.2% (95% CI, 4.1% to 6.5%). The point prevalence of cancer was higher in patients who had extensive screening than in those who had more limited screening initially (odds ratio [OR], 2.0 [CI, 1.2 to 3.4]) but not at 12 months (OR, 1.4 [CI, 0.89 to 2.1]). Cancer prevalence increased linearly with age and was 7-fold higher in patients aged 50 years or older than in younger patients (OR, 7.1 [CI, 3.1 to 16]).

LIMITATION: Variation in patient characteristics and extensive screening strategies; unavailability of long-term mortality data.

CONCLUSION: Occult cancer is detected in 1 in 20 patients within a year of receiving a diagnosis of unprovoked VTE. Older age is associated with a higher cancer prevalence. Although an extensive screening strategy initially may detect more cancer cases than limited screening, whether this translates into improved patient outcomes remains unclear.

PRIMARY FUNDING SOURCE: None. (PROSPERO: CRD42016033371).