The quality of informed consent forms for oncology clinical trials
Authors: W. Y. Cheung, G. R. Pond, R. J. Heslegrave, L. Potanina, L. L. Siu
Journal: Journal of Clinical Oncology (2008)

6544 Background: Informed consent forms (ICF) play an integral role in the consent process for clinical trials (CT) by serving as a guide for discussion between the research team and study subjects. Our aims were to compare the quality of ICF among different 1) trial phases, 2) funding sources, 3) oncology subspecialties, 4) disease settings and 5) intervention modalities. Methods: ICF for prospectively conducted CT approved at the Princess Margaret Hospital from 2005–2007 were examined for their content on benefits and risks, alternatives, voluntary participation and confidentiality. Readability was assessed with the Flesch Reading Ease (FRE) score (range 0 to 100 with higher scores denoting greater reading ease) and Reading Grade Level (RGL). Results: Of the 262 evaluable CT, ICF contained an average of 3,982 words, 379 sentences and 10.5 pages. The mean FRE score and RGL were 61.2 and 7.4, respectively. All ICF explicitly stated that the CT was investigational. Only 2 (1%) promised direct personal benefits, 16 (6%) suggested the chance of cure or prolonged survival and 89 (34%) indicated a potential for tumor response. Conversely, 239 (91%) mentioned the risk of serious harms, 217 (83%) admitted that some side effects could be unknown or unpredictable and 126 (48%) reported hospitalization or death as a possibility. Alternatives to participation, right to withdraw from study and data confidentiality were addressed in 242 (92%), 254 (97%) and 260 (99%) ICF, respectively. Multivariate comparisons of benefit and risk descriptions and readability were tabulated (see table). ICF for hematology CT were most likely to highlight major risks (p=0.02), while readability was better in phase I CT and in those which were conducted by medical oncology, sponsored by governmental agencies and involved systemic therapy (all p<0.05). Conclusions: ICF provided a realistic overview of the benefits and risks of CT, although the risk of hospitalization or fatality was underreported. While readability was acceptable in most ICF, these documents remained lengthy. Parameter N Description of Benefits and Risks Readability % of CFs Stating CA May Improve p-value % of CFs Stating Risk of Death p-value Mean FRE p-value Mean RGL p-value Phase I I/II II III 57 25 90 90 26.3 24.0 33.3 42.2 0.12 43.9 44.0 48.9 51.1 0.28 62.9 58.5 61.2 60.8 0.002 7.1 7.8 7.3 7.5 0.001 Funding Academic Gov't Industry Unknown 36 39 158 29 38.9 41.0 29.1 42.9 0.27 27.8 51.3 56.3 25.0 0.16 60.4 64.1 60.8 60.8 0.003 7.5 6.9 7.5 7.4 <0.001 Specialty MedOnc Heme RadOnc Surgery 101 60 52 49 38.6 26.7 42.3 24.5 0.14 51.5 70.0 28.9 34.7 0.02 62.4 61.2 60.2 59.8 0.003 7.2 7.4 7.5 7.6 0.002 Setting Diagnostic Curative Metastatic 28 73 161 32.1 34.3 34.2 0.95 17.9 38.4 57.8 0.23 59.8 60.3 61.8 0.47 7.6 7.5 7.3 0.56 Modality SystemicTx Other 193 69 34.2 33.3 0.20 87.3 12.7 0.06 61.8 59.6 0.02 7.3 7.7 0.001 %: percentage; CFs: consent forms; CA: cancer; FRE: Flesch Reading Ease score; RGL: Reading Grade Level; Gov't: government; MedOnc: medical oncology; Heme: hematology; RadOnc: radiation oncology; SystemicTx: systemic therapy; p-values listed are based on multivariate analyses. No significant financial relationships to disclose.