¹ Death due to any cause.
² Defined as death due to malignant disease itself, or death due to complications of treatments or procedures to diagnose or treat cancer.
³ Risk of bias was high in two included studies (Piccioli 2004b; Prandoni 2016). Piccioli 2004b terminated early after inclusion of only 201 participants after 5 years for several reasons. First, only five of more than 40 potential participating centres could contribute participants to study. Second, some medical ethics committees rejected the protocol because of absence of screening for occult cancer in the control group, other centres could not start because the proposed extensive screening was judged unethical. Finally, identification of cancer at an apparent early stage in extensive screening group led to an increasing tendency among physicians in participating hospitals to initiate screening for cancer in control participants. Prandoni 2016 study terminated early due to low recruitment rate and failure to show an appreciable advantage of CT‐based strategy over control strategy for detection of cancer.
⁴ Fatal pulmonary embolism (PE). PE diagnosed "on the basis of a lung scan indicating a high probability of its presence, as indicated by the presence of new or enlarged areas of segmental perfusion defects with ventilation‐perfusion mismatch; an abnormal perfusion scan with documentation of new or recurrent deep vein thrombosis (DVT); the presence of non‐enhancing filling defects in the central pulmonary vasculature on helical computed tomography; a finding of intraluminal filling defects on pulmonary angiography; or evidence of fresh PE at autopsy" (Lee 2003b). Fatal PE including probable fatal PE and unexplained sudden death used if reported, as defined by individual studies.
⁵ Frequency of recurrent VTE. Recurrent PE or DVT diagnosed if a previously compressible proximal venous segment or segments could no longer be compressed on ultrasonography or if there were constant intraluminal filling defects in two or more projections on venography. Unequivocal extension of the thrombus required for diagnosis of recurrence if results abnormal on previous testing (Lee 2003b)
⁶ Early‐stage malignancies, defined as T1 or T2 without locoregional or distant metastases (N0 M0).
⁷ Quality of evidence downgraded for imprecision due to low number of events. Evidence downgraded further as risk of bias high in Piccioli 2004b. Study terminated early after inclusion of only 201 participants after five years for several reasons. First, only five of more than 40 potential participating centres could contribute participants to study. Second, some medical ethics committees rejected the protocol because of absence of screening for occult cancer in the control group, other centres could not start because the proposed extensive screening was judged unethical. Finally, identification of cancer at an apparent early stage in extensive screening group led to an increasing tendency among physicians in participating hospitals to initiate screening for cancer in control participants.
⁸ Advanced‐stage malignancies, defined as T3 with locoregional or distant metastases (N1 or M1).
⁹ Time to cancer diagnosis, as defined in included studies.
¹⁰ Frequency of an underlying cancer diagnosis (i.e. number of times cancer diagnosed through screening following an unprovoked VTE as defined in included studies) at time of VTE presentation and overall over follow‐up period.

¹ Death due to any cause.
² Quality of evidence downgraded as risk of detection bias high for one study as outcome assessors not blinded to treatment (Robin 2016).
³ Defined as death due to malignant disease itself, or death due to complications of treatments or procedures to diagnose or treat cancer.
⁴ Fatal pulmonary embolism (PE). PE diagnosed "on the basis of a lung scan indicating a high probability of its presence, as indicated by the presence of new or enlarged areas of segmental perfusion defects with ventilation‐perfusion mismatch; an abnormal perfusion scan with documentation of new or recurrent deep vein thrombosis (DVT); the presence of non‐enhancing filling defects in the central pulmonary vasculature on helical computed tomography; a finding of intraluminal filling defects on pulmonary angiography; or evidence of fresh PE at autopsy" (Lee 2003b). Fatal PE including probable fatal PE and unexplained sudden death used if reported, as defined by individual studies.
⁵ Frequency of recurrent VTE. Recurrent PE or DVT diagnosed if a previously compressible proximal venous segment or segments could no longer be compressed on ultrasonography or if there were constant intraluminal filling defects in two or more projections on venography.
⁶ Quality of evidence downgraded for imprecision due to low number of events.
⁷ Time to cancer diagnosis, as defined in included studies.
⁸ Frequency of an underlying cancer diagnosis (i.e. number of times cancer diagnosed through screening following an unprovoked VTE as defined in included studies) at time of VTE presentation and overall over follow‐up period.