[Analysis of the effect of selection in a therapy study]

282 patients with SCLC were treated for the first time at the Chest-Hospital Heidelberg-Rohrbach from July 1981 until November 1983. Only 85 were integrated into a German randomized multicenter study of combined chemo- and radiotherapy, the other 197 were treated with individual therapeutic regimens. Generally, randomized and non-randomized patients were similar with respect to the prognostic factors and survival, but the group of excluded patients was more heterogeneous. Further analysis revealed prognostic relevance to surgical treatment, emergency treatment, various contra-indications and a poor general condition, but patients older than 70 years should not be generally excluded. General implications for clinical trials are that the clinical and methodological relevance of each criterion of exclusion should be critically examined and the baseline data on all excluded patients collected prospectively.