Background: Outcome-expectation beliefs and knowledge may ultimately influence behavior for cancerprevention. The aims of this study were to measure changes in knowledge and beliefs about cancer preventionbefore and after viewing a television advertisement and identify the factors affecting receptivity to its messages.Materials and
Methods: A one-group pretest-posttest design was used in this study of 1,000 individuals aged 20to 65 years who were recruited online in November 2014. The outcome variables included cancer preventionbeliefs based on the Health Belief Model (five items) and knowledge about risk factors for cancer (seven items).
Results: Perceived susceptibility, perceived benefits, and self-efficacy increased significantly and their perceivedseverity and perceived barriers decreased significantly, after participants viewed the television advertisement.Correct responses to questions about risk factors also increased significantly, except for smoking. The mainfactors affecting changes in the outcome variables were age, interest in cancer prevention, social network,satisfaction with the ad, and pretest scores.
Conclusions: Television advertisements with positive frameworkscan be an efficient channel of improving beliefs and knowledge about cancer prevention in a short period. Thecontinuous development of intervention materials that consider the demographics, needs, and satisfaction ofthe target group will be necessary for future studies.