The length of consent documents in oncological trials is doubled in twenty years.

BACKGROUND The aim of the study was to investigate whether the length of informed consent documents (ICDs) for oncological trials have increased from 1987 to 2007 and analyze the content of the ICDs. DESIGN In total, 87 ICDs from oncological trials approved by the Regional Committee for Medical and Health Research Ethics (REC) in the central region of Norway from 1987 to 2007 were analyzed. A list of 17 basic (fundamental medical and ethical aspects) and 30 formal (juridical aspects, financing, insurance and storage of data) content components was constructed based upon international and REC guidelines for ICDs. The number of words and presence of components were registered for all ICDs. RESULTS The mean length of the ICDs increased from 338 (range 276-464) words in 1987-1990 to 1087 words (range 399-2345) in 2005-2007. The number of components increased from nine to 25 during the same period. Basic components increased steadily from seven in 1987-1989 to 14 in 2005-2007 while the components concerning formalities increased substantially from two to 11. CONCLUSIONS The increased length of the ICDs is explained by an increased complexity of the documents and especially more information about formalities. This development increasingly demands competent readers and might prohibit truly informed consents.