[Etretinate in the prevention of recurrences of superficial bladder tumors. Clinical trial using the double-blind method].

The authors undertook a double blind study in a group of 20 patients of the possible effectiveness of etretinate in the prevention of recurrences of superficial tumours of the bladder (with the exception of class IV carcinomas). No difference was seen in the course of the two series. These conclusions were not in agreement with those previously published.