Zacharski 1981.

Study characteristics
Methods	Trial acronym: Veterans Administration Study No. 75 Design: multicentre RCT, type of analyses not reported Median duration of follow‐up: not reported, maximum follow‐up was approximately 95 weeks in warfarin group and 94 weeks in control group (approximated from figure)
Participants	Patients with small‐cell lung carcinoma treated with chemotherapy and radiotherapy Mean age: 58.9 (SD not reported) in warfarin group: 59.8 (SD not reported) in control group Gender, n (%) males: 50 (100%) Metastatic disease: extensive cancer in 13 (52%) in warfarin group; 12 (48%) in control group Previous VTE: not reported
Interventions	Intervention: warfarin at doses to prolong the prothrombin time to approximately 2 times the control value Control: no warfarin Median duration of warfarin administration: 27 weeks
Outcomes	Primary efficacy outcomes: survival and cancer response to treatment
Notes	Funding: VA Cooperative Studies Program Disclosure of potential conflicts of interest: not reported, no COI forms available Publication format: full‐text publication
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "subjected to computer randomization." Comment: adequate method of sequence generation.
Allocation concealment (selection bias)	Low risk	Quote: "subjected to computer randomization." Comment: adequate method of allocation concealment.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Comment: it is not reported whether participants, physicians, and outcome assessors were blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "No patient has been lost to follow‐up." Comment: all enrolled participants were included in the analysis.
Selective reporting (reporting bias)	Unclear risk	Comment: bleeding was addressed in the results section, but not mentioned in the methods section.