Retrospective, single-centre study with modest sample size and surrogate endpoint (mutation status prediction); requires prospective multicentre validation before clinical use, as stated by the authors.
Post hoc analysis of a phase II trial with small sample (n=29) and surrogate/exploratory endpoints; findings are hypothesis-generating and require validation in larger populations.
A well-designed secondary analysis of prospectively acquired imaging data with independent expert assessment and rigorous statistical methods, but limited to a single-centre cohort of 35 patients evaluating a surrogate imaging quality endpoint rather than clinical outcomes.