Using an informed consent in mammography screening: a randomized trial

Spanish women do not make an informed choice regarding breast cancer screening (BCS). Our aim was to evaluate the impact of receiving information regarding real BCS benefits and risks on knowledge, attitude, decision, feelings, and worries about cancer. Randomized controlled clinical trial of 355 women aged between 45 and 67 years, 177 and 178 assigned to the intervention group (IG) and control group (CG), respectively. After breast screening, women received either Nordic Cochrane Centre information on BCS or standard information. The primary outcome (knowledge) was determined from questionnaire administered at baseline and after a month. Answers were scored from 0 to 10 and scores of 5 or more indicated that women were well informed (had "good knowledge"). Questionnaires regarding attitudes, future screening intentions, and psychosocial impact were also administered. The Chi-squared and Student's t-tests were used to compare qualitative and quantitative variables, respectively. Good knowledge was acquired by 32 (18.10%) IG women and 15 (8.40%) CG women (P = 0.008). Mean scores from first to second interview increased from 2.97 (SD 1.16) to 3.43 (SD 1.39) in the CG and from and from 2.96 (SD 1.23) to 3.95 (SD 1.78) (P = 0.002) in the IG. No differences were found in the secondary endpoints. Women receiving information based on the Nordic Cochrane Centre document were better informed. This means of providing information is not very efficacious, nor does it modify attitude, decision, feelings, or worries about cancer.