Maurer 1988.

Methods	Method of randomisation not clear (patients randomised within each clinical group)
Participants	413 children (age nm: an inclusion criterion for this study was age < 21 years; 240 males and 173 females) with rhabdomyosarcoma or undifferentiated sarcoma (clinical group III or IV; primary disease) No prior treatment Prior cardiac dysfunction nm
Interventions	Chemotherapy without doxorubicin (N = 208) versus chemotherapy including doxorubicin (N = 205) Cumulative doxorubicin dose nm (according to protocol 300 mg/m2); peak dose (i.e. the maximal dose received in one week) 60 mg/m2; infusion duration nm All patients received radiotherapy to the primary lesion (dose adjusted to age); in case of pulmonary metastases patients received pulmonary irradiation No surgery No cardioprotective interventions
Outcomes	Overall survival (defined as time from start of treatment to death) Tumour response (complete remission defined as complete disappearance of all signs and symptoms of disease; partial remission defined as at least 50% reduction in gross disease in widest diameter) Cardiotoxicity (clinical heart failure defined as congestive heart failure).
Notes	Length of follow‐up nm Exact age in treatment and control group nm, but it was balanced between treatment groups
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	It was stated that this was a randomised study, but no further information on the methods of randomisation was provided
Allocation concealment (selection bias)	Unclear risk	It was stated that this was a randomised study, but no further information on the methods of randomisation was provided
Blinding of participants and personnel (performance bias)	Unclear risk	No information on blinding of participants and personnel was provided
Blinding of outcome assessment (detection bias): overall survival	Low risk	No information on blinding of outcome assessors was provided, but since this is not applicable for overall survival we judged this as a low risk of bias
Blinding of outcome assessment (detection bias): outcomes other than overall survival	Unclear risk	No information on blinding of outcome assessors was provided for tumour response and cardiotoxicity
Incomplete outcome data (attrition bias): overall survival	Unclear risk	It was not clear if all participants were included in the analyses
Incomplete outcome data (attrition bias): tumour response	Low risk	Only 1% of participants were not evaluable for this outcome
Incomplete outcome data (attrition bias): anthracycline‐induced cardiotoxicity	Unclear risk	It was not clear if all participants were included in the analyses
Selective reporting (reporting bias)	Low risk	There was no protocol mentioned in the manuscript (and we did not search for it), but all expected outcomes were reported
Other bias	Unclear risk	Block randomisation in unblinded trials: unclear (see information provided at earlier associated risk of bias items) Baseline imbalance between treatment arms related to outcome (prior cardiotoxic treatment, age, sex and/or prior cardiac dysfunction): unclear (unclear if prior cardiotoxic treatment was balanced between treatment arms; age, sex, prior cardiac dysfunction were balanced between treatment arms) Difference in length of follow‐up between treatment arms: unclear (not reported) Inappropriate influence of funders: unclear (the study was supported by US Public Health Service Grants, but no information on the influence of funders was provided)