Prandoni 2016

Methods	Study design: multicentre, randomised controlled trial.
Participants	Country: Italy. Setting: hospital. Number of centres: 5. Number of participants: 195 Age (mean (SD)): extensive screening group: 69.3 (14) years; control group: 69.0 (14) years. Sex: extensive screening group: 54 M/44 F; control group: 47 M/50 F. Inclusion criteria: people with an objectively diagnosed, first episode of unprovoked VTE, in whom a routine initial screening for cancer was normal. Exclusion criteria: history of previous documented episodes of VTE, aged < 18 years, pregnant, unable to attend follow‐up visits because of geographic inaccessibility, had known allergy to contrast medium or had a CT scan of torso for any reasons within 6 months from presentation.
Interventions	Screening procedure: extensive screening with mandatory CT scan of thorax, abdomen and pelvis together with haemoccult test or any test at physician's discretion according to good clinical practice. Control: personalised strategy consisting of additional testing based on physicians' judgements and participants' preferences, including a 'no‐further testing' option. Duration: 3, 6, 12 and 24 months' follow‐up in which participants were asked about general health, history of recent hospital admissions and occurrence of signs and symptoms suggestive of cancer. Cancer outcomes that presented during follow‐up were detected based on clinical features that would prompt diagnostic imaging or cancers that were occasionally detected by screening that was independent of the diagnosis of VTE.
Outcomes	Primary outcomes: cancer‐related mortality (defined as death due to malignancy or death due to the complications of the diagnostic or surgical procedures performed to diagnose or treat cancer) and incidence of newly discovered cancer. Secondary outcomes: cancer stage, using the TNM classification, at which tumours were diagnosed in the 2 study groups; and incidence of cancer‐related mortality in the 2 randomisation groups.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Concealed allocation was ensured by employing serially numbered, opaque, sealed envelopes. Each participating centre was initially assigned a lot of 20 envelopes, while subsequent allocations were in lots of 10, as needed."
Allocation concealment (selection bias)	Low risk	Quote: "Concealed allocation was ensured by employing serially numbered, opaque, sealed envelopes. Each participating centre was initially assigned a lot of 20 envelopes, while subsequent allocations were in lots of 10, as needed."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Comment: blinding of participants in extensive screening group and study personnel not done but review authors judged that outcome and outcome measurement were not likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: investigators performing the follow‐up visits blinded to participants' randomisation groups'.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: all losses to follow‐up accounted for.
Selective reporting (reporting bias)	Low risk	Comment: primary and secondary outcomes clearly prespecified and reported.
Other bias	High risk	Comment: interim analysis scheduled after inclusion of approximately half of planned sample size. Based on results of this analysis, study promoters decided to stop study enrolment because of low recruitment rate and of failure to show an appreciable advantage of CT‐based strategy over control strategy for detection of occult cancers.