In this respect retrolective studies have been applied to examine the therapeutic potential of adjuvant mistletoe treatment.
Material and methods: The databases PubMED, EMBASE, AMED, and CAMbase were used to identify retrolective studies in mistletoe treatment.
From these, 10 duplicates and 3 descriptive literature and popular articles had to be removed, leaving 4 retrolective studies on mistletoe preparations and patients' survival conducted between 1985 and 2002, with a total of 3324 patients (2454 per protocol) recruited in 17-35 German and Swiss hospitals, wards and private practices.
Discussion: Although we found a positive treatment effect, there are several methodological limitations with respect to the retrolective study design.
According to Feinstein (1985), a cohort study is described as retrolective
if the treatment had already been started before the study, and as prolective if allocation to the study or control treatment was made only after the study had commenced.