The objective of the current study was to determine the influence of media information on the opinions and feelings of patients with cancer and to measure the factors that affected the decision-making process and physician–patient communication. The study consisted of a sequence of two nationwide surveys across the same dynamic target population of 2600 unselected patients with cancer who attended one of 13 centres throughout Italy. The authors measured the changes in patients’ opinions and attitudes at the peak of a media campaign promoting the Di Bella therapy, an unproven cancer treatment method, and after the publicised demonstration of its ineffectiveness. The same 10-item questionnaire was used for each survey. Opinions and feelings changed in the two surveys according to the way the media described the efficacy of the treatment, but physician–patient communication and the decision-making process remained unchanged. Multivariate analysis confirmed the enormous influence of the media on patient opinions, feelings of hope and confusion, but not on physician–patient communication or the decision-making process. Educational level influenced almost all of the studied factors, and communication and decision-making were also influenced by the patients’ gender and place of residence. There was no significant correlation with patient age.