Novel biomarkers to detect occult cancer in patients with unprovoked venous thromboembolism: Rationale and design of the PLATO-VTE study

Occult cancer is detected in about 5% of patients with unprovoked venous thromboembolism (VTE) in the 12 months following VTE diagnosis. Current guidance suggests conducting a ‘limited’ cancer screening in these patients, consisting of medical history taking, physical examination, routine blood tests, chest X-ray, and age- and gender-specific testing, over full-body imaging. However, almost half of underlying cancers remain undetected with this approach. Blood-based liquid biopsies may provide an attractive addition or alternative to current cancer screening strategies, with a potentially higher detection rate while avoiding radiation or invasive testing. The PLATO-VTE study is an ongoing, investigator-initiated, multinational, prospective, observational cohort study comparing the sensitivity of novel biomarkers for detecting cancer with that of limited cancer screening in the setting of unprovoked VTE. Patients older than 40 years with a first episode of unprovoked VTE are eligible, while those with major and minor transient provoking risk factors for VTE are excluded. Patients undergo standard-of-care ‘limited’ cancer screening and are followed for 12 months for the occurrence of cancer. A blood sample for biomarker analysis is drawn within 10 days; a second sample is taken at 3 months to assess test result consistency over time. Three biomarkers are assessed: platelet mRNA, circulating tumor DNA, and plasma proteomics analysis. The sensitivity and predictive value of the biomarkers at baseline will be compared with those of limited screening. The results from the PLATO-VTE study may lead to reconsider current approaches for cancer screening in patients with unprovoked VTE.