The present systematic review was performed under the auspices of the European Lung Cancer Working Party (ELCWP) in order to determine the role of early intermediate criteria (surrogate markers) in determining treatment efficacy instead of survival in patients with lung cancer.

Preliminarily, the level of evidence for the use of overall survival to evaluate treatment efficacy was reviewed. Nine questions were then formulated by the ELCWP. After reviewing the literature with experts on these questions, it can be concluded that overall survival is still the best criterion for predicting treatment efficacy in lung cancer.

Some intermediate criteria can be early predictors, if not surrogates, for survival despite limitations in their potential application: these include time-to-progression, progression-free survival, objective response, local control after radiotherapy, downstaging in locally advanced non-small cell lung cancer (NSCLC), complete resection and pathological TNM in resected NSCLC, and a few circulating markers.

Other criteria assessed in these recommendations are not currently adequate surrogates of survival in lung cancer.