Introduction : Despite the large number of clinical trials on breast cancer, patient-related factors such as perioperative anxiety and level of knowledge about the disease and treatment have not been included in mainstream research efforts. This randomized trial was performed to evaluate the impact of information, provided preoperatively, on anxiety and knowledge of women undergoing mastectomy for breast cancer.Methods : Sixty consecutive patients with breast cancer, admitted for a mastectomy, as primary treatment for breast cancer, with no previous cancer history, were randomized to receive structured information (short video about practical aspects of the hospital stay, surgical and adjuvant treatment) in addition to the routine informed consent procedure for surgery or the routine informed consent only. Anxiety and subjective knowledge levels were measured with the visual analogue scales; in addition, knowledge was assessed with a questionnaire.Results : There was no significant effect of the additional information on perioperative anxiety or knowledge (subjective). Significantly more patients in the additional information group correctly listed all major available treatment options compared to the patients that received routine information (preoperatively 54% vs. 19%; p = 0.0101; 7 days postoperatively 50% vs.19%; p = 0.0367).Conclusions : Use of an informational video, preoperatively, did not significantly affect perioperative anxiety or subjective knowledge. Additional research is needed on effective delivery of disease-and treatment-specific information perioperatively.