Meta-analyses dealing with the treatment of thoracic malignancy (non-small cell lung cancer, small cell lung cancer and mesothelioma) were reviewed including isolated ones, based on individual data from clinical trials, or conducted in the context of a systematic review of the literature Their results have changed clinical practice, notably by validating radiochemotherapy for patients with unresectable limited diseases, adjuvant chemotherapy for resectable non-small cell lung cancer and by identifying the most active drugs. However it is important to understand the limits of their methodology in order to avoid inappropriate interpretations.