Maurer 1997.

Study characteristics
Methods	Trial acronym: CALGB Protocol 8534, run by the Cancer and Leukemia Group B study Design: multicentre RCT; intention‐to‐treat analyses not reported Median duration of follow‐up: 69 months in those still alive
Participants	Patients with limited‐stage small‐cell lung cancer receiving chemotherapy and radiotherapy Participants aged ≥ 60 years: 57.6% Gender, n (%) males: 225 (64.8%) Metastatic disease: none Previous VTE: not reported
Interventions	Intervention: warfarin 10 mg/day for the first 3 days and then at a dose to maintain the prothrombin time between 1.4 and 1.6 times the local institutional control standards Control: no warfarin Warfarin was continued through the complete course of chemotherapy and radiotherapy and stopped 3 weeks after the last cycle of chemotherapy. Warfarin was administered for a median of 112.5 days.
Outcomes	Primary outcomes: overall survival and cancer response to therapy Secondary outcomes: failure‐free survival, disease‐free survival, patterns of relapse, toxicity
Notes	Funding: grants from the National Cancer Institute, Bethesda, MD 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)	Unclear risk	Quote: "Patients were randomized to receive warfarin or no warfarin." Comment: method of sequence generation not reported.
Allocation concealment (selection bias)	Unclear risk	Quote: "Patients were randomized to receive warfarin or no warfarin." Comment: method of allocation concealment not reported.
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	Unclear risk	Comment: Table 6 of the study full‐text indicated that not all randomised participants were analysed, but the exact numbers were not reported.
Selective reporting (reporting bias)	Unclear risk	Comment: only the outcomes of overall survival and complete tumour response were specified in the methods section. All other outcomes were addressed in the results section only, including the survival analyses at 8 months, and 2, 3, and 4 years. Only the 8 months' analyses were reported to be exploratory.