Relearning an old lesson: stopping trials early

A well designed and delivered clinical trial is the main tool to define whether medical interventions ‘work’, and how well. As such, they are potent weapons in the armoury of medical progress—and like all potent weapons need to be used with care. In this month's Thorax, Koegelenberg et al ( see page 857 ) report the findings of a trial comparing the diagnostic accuracy of closed pleural biopsy (Abrams needle) and cutting needle pleural biopsy...