Because unprovoked venous thromboembolism (VTE) may herald an occult cancer, researchers have been interested in uncovering patterns that may link these phenomena. However, a recent report in Thrombosis Research found no relationship between the location of an unprovoked VTE and the location of cancer within the body.
The study was a post hoc meta-analysis of data from 2300 adult patients who had experienced unprovoked VTE. Sixteen patients with deep vein thrombosis (DVT) in upper extremities had been excluded from the original dataset of 2316 patients. The primary study outcome was 12-month period prevalence of occult cancer following unprovoked VTE (DVT, pulmonary embolism [PE], or both). Associations between location of VTE and occult cancer were also evaluated.
The most common type of unprovoked VTE in this study population was DVT only, which affected 53% of patients. PE alone affected 31% of patients and a combination of DVT and PE affected 16% of patients.
Patients with DVT only showed a pooled 12-month period prevalence of cancer of 5.6% (95% confidence interval [CI]: 4.4%-7.2%). For those with PE only, this rate was 4.3% (95% CI: 2.7%-6.9%), and for those experiencing both DVT and PE, this rate was 5.6% (95% CI: 1.7%-15.5%). The abdomen was the most common location for occult cancers, reflecting 68.4% of cancer cases.
Of patients who had cancer and experienced DVT only, 68.4% (95% CI: 57%-78%) of these cancers were abdominal or pelvic. For patients who had PE only, this location represented 65% (95% CI: 48%-79%) of cancers, and for patients with DVT and PE, this location represented 81.2% (95% CI: 54.3%-96%) of cancers.
The thoracic region accounted for 25.3% of cancers in patients with DVT only, 30% in patients with PE only, and 12.5% in patients with DVT and PE. For each type of VTE, areas other than thoracic or abdominal and pelvic regions accounted for 5% to 6.3% of cancer cases.
The study authors concluded that although approximately two-thirds of occult cancers were identified in the abdomen during the 12-month period following unprovoked VTE, the location of an unprovoked VTE was not found to be associated with a cancer’s location in the body.
1. Jara-Palomares L, van Es N, Praena-Fernandez JM, et al. Relationship between type of unprovoked venous thromboembolism and cancer location: an individual patient data meta-analysis [published online February 13, 2019]. Thromb Res. doi: 10.1016/j.thromres.2019.02.011