An innovative analysis from a team of Cochrane France researchers suggests that systematic reviews of multiple treatments provide a fragmented, out-of-date panorama of the available evidence. These findings question the current approach to synthesizing evidence and suggest that it does not fully address the needs of patients and clinicians.

The article, recently published in BMC Medicine, is co-authored by Perrine Créquit, Ludovic Trinquart, Amélie Yavchitz, and Philippe Ravaud, from Cochrane France and INSERM U1153 METHODS team, Paris, France.

Multiple treatments are now frequently available for the same disease. Patients and physicians need a comprehensive, up-to-date synthesis of evidence for all competing treatments to know which treatments work best. The author team took a specific example - second-line treatments of advanced non-small cell lung cancer and attempted to assess whether such a complete and up-to-date evidence synthesis was available over time.

To carry out this assessment, the authors performed a series of systematic overviews and networks of randomized trials to assess the gap between evidence covered by systematic reviews and available trials. They also propose a new approach to evidence synthesis, called “live cumulative network meta-analysis”, which outlines how to switch from a series of systematic reviews — performed at different points in time, frequently out-of-date, and focusing on specific treatments (many treatments being not considered) – to a single systematic review covering all treatments, with network meta-analyses, and updated continuously to incorporate the results of new trials when they become available.