Recurrence-free survival as a putative surrogate for overall survival in phase III trials of curative-intent treatment of colorectal liver metastases: Systematic review

Table 1 Quality assessment of selected randomized clinical trials evaluated by Cochrane Risk-of-Bias Tool (Risk of bias per study)

Criteria	Langer	Portier	Nordlinger	Ychou	Primrose
Random sequence generation	Unclear	Low	Low	Low	Low
Allocation concealments	Low	Low	Low	Low	Low
Blinding of participants and personnel1	Low	Low	Unclear	Low	Low
Blinding of outcome assessment1,2	Low	Low	Low	Low	Low
Incomplete outcome data	Unclear	Low	Low	Unclear	Low
Selective reporting	Low	Low	Low	Low	Low
Other bias	Unclear	Low	Low	Low	Low

¹Blinding is not possible;

²Implementation of a protocol for postoperative management was considered the best alternative.