Kubista 2007.

Methods	Randomised placebo‐controlled trial
Participants	102 postmenopausal women with initially stage I or II, oestrogen receptor–positive (ER+), previously untreated, core‐biopsy proven, invasive breast cancer without evidence of metastatic spread; any endocrine or enzyme modulator therapy was stopped ≥ 3 months before randomisation. Mean age 65 years. Mean time since menopause 17 years
Interventions	Tibolone 2.5 mg Placebo Administered for 14 days
Outcomes	Ischaemic stroke, breast tumoural markers
Notes	Tumoural markers (surrogate outcome) measured as median/mean Timing: March 2003 to April 2005 Location: unclear Multi‐centre: 14 sites in 5 countries (not provided)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided
Allocation concealment (selection bias)	Unclear risk	No information provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo‐controlled and defined as "double‐blind" (1 pill administered per day)
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not specified, but given the nature of the outcome assessed (stroke), its evaluation is likely to be "objective"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Stroke evaluated referring to the "all subject treated group"
Selective reporting (reporting bias)	Low risk	Some of the outcomes indicated in the protocol were assessed and reported in the study publication. Those not reported were of no interest for the review. Additional data on ischaemic stroke were available in the study publication and were included in this review
Conflict of interest	High risk	Financed by the drug manufacturer. Two study authors were employees of the drug manufacturer