SUMMARYCommunicating personalized, risk-based breast cancer screening information is challenging. In co-creation with women, information needs were assessed and information prototypes and visualizations were developed. Explaining risk-based screening with underlying risk factors should be done through unambiguous information with a cordial/personal tone, accompanied by visualizations. To meet women’s needs and experts’ views, layered information is recommended. KEYWORDS: Citizen participation, risk communication, personalized cancer screening, co-creationBACKGROUNDBreast Cancer (BC) screening will likely become more personalized, based on risk categories (i.e., risk stratification) (RIVM, 2022). This implies that complex information needs to be communicated, including multifaceted risk information (i.e. no breast abnormality found, risk category with probability information, and corresponding advice for follow-up screening interval/method). This risk information is difficult for women to understand (Fagerlin et al., 2007; Zikmund-Fisher, 2012), especially for those with lower health literacy (HL) levels. This study aimed to design informational materials, including (interactive) visualizations, of risk information in personalized BC screening through co-creation with women from the target group. METHODSThree co-creation sessions were conducted with women between 40-50 yrs not yet invited for BC screening (session 1 n=4, 2 low HL; session 2-3 n=6, 3 low HL) to gain insight into information needs and to co-design informational materials, including risk visualizations. During the sessions, women completed creative assignments (e.g., sensitizing booklet, process mapping of screening process, 5W1H method) and created/evaluated visualizations of risk information. Resulting prototypes were further evaluated by women between 54-62 yrs familiar with BC screening in two additional co-creation sessions (session 1 n=2, 1 low HL; session 2 n=2, 0 low HL). Experts in epidemiology and personalized screening evaluated prototype content on accuracy. Adapted prototypes were tested through think-aloud interviews in a new group of women (n=9, 40-74 yrs). The three-phase structure for generative data analysis was used for analysis (Visser et al., 2005). Notes, photos, created materials, and interviews were summarized, and main themes were identified. RESULTSWomen had a positive attitude towards personalized, risk-based BC screening. However, the concept of risk-based screening was not fully understood in the initial co-creation sessions. Women wrongly believed it would help them identify personally relevant and modifiable risk factors. But actually, personalization is at group level (i.e., risk category) and not on individual level, therefore feedback on individual risk factors is not possible. Besides, many risk factors cannot be influenced (e.g. age of first menstruation). Nonetheless, women indicated that they needed an elaboration on the implications of being assigned to a risk category. They said to initially only want information applying to their own risk category, but at the same time also need a comparison to the other categories. There were some inconsistencies between women’s and experts’ views. For example, the classification of risk categories did not match women’s perceptions (i.e., absolute numbers indicating high risk were not perceived as high risk). Experts stressed the importance of precise and nuanced information (e.g., a range to indicate absolute risks instead of one number) where women wanted unambiguous information (e.g., no range to indicate absolute risks but one number). Concerning information presentation, women appreciated comprehensible language with a cordial and personal tone, accompanied by visualizations. Prototypes tested during think-aloud interviews contained layered information to emphasize the personalized risk-based information first and later provide the context information about the risk-based BC screening program. These prototypes were generally well understood and evaluated, although some visualizations (e.g., the risk factors hormones and breast tissue and the flow-chart of the procedure for risk-based screening) need further improvement to improve understanding. DISCUSSIONThe positive attitude towards personalized, risk-based BC screening is in line with previous studies (Rainey et al., 2020). What our study adds are specific insights into information needs and the complexities involved in adequately understanding the complex message that women will receive. Both aspects prioritized by women (e.g., indicating global risk factors) and by experts (e.g., absolute risk categories with explanations) were addressed in the final prototypes created. Layered information seems needed, e.g., providing only the information of the specific risk category with additional information about the other categories for those interested. CONCLUSIONSInformational materials about personalized BC screening should emphasize the idea of risk stratification into categories instead of on a personal level, including general instead of personal risk factors. Layered information is recommended to meet both women’s needs and experts’ views. Developed materials, including the risk visualizations, were well understood and evaluated, although some visualizations need further improvement. ACKNOWLEDGEMENTSThe authors would like to thank the participants in the co-creation sessions and think-aloud interviews. We also thank the RIVM Centre for Population Screening (RIVM-CvB) and the Dutch Breast Cancer Association (BVN) for their advisory role in the study. Mirjam Fransen, Ellen Uiters, Mireille Broeders, Carla van Gils, Linda Rainey, Harry de Koning, Lidewij Henneman, and Yasmina Okan are thanked for their expert opinion. This study was supported by ZonMw (50-53125-98-163). REFERENCES Fagerlin, A., Zikmund-Fisher, B. J., & Ubel, P. A. (2007). "If I'm better than average, then I'm ok?": Comparative information influences beliefs about risk and benefits. Patient Education and Counseling, 69(1-3), 140-144. Doi: 10.1016/j.pec.2007.08.008 Rainey, L., van der Waal, D., & Broeders, M. J. M. (2020). Dutch women's intended participation in a risk-based breast cancer screening and prevention programme: a survey study identifying preferences, facilitators and barriers. BMC Cancer, 20(1), 965. Doi: 10.1186/s12885-020-07464-2RIVM. (2022). Bevolkingsonderzoek borstkanker - professionals: actuele ontwikkelingen. National Institute for Public Health and the Environment. Retrieved June 2022 from https://www.rivm.nl/bevolkingsonderzoek-borstkanker/professionals/actuele-ontwikkelingenVisser, F. S., Stappers, P. J., van der Lugt, R., & Sanders, E. B. N. (2005). Contextmapping: experiences from practice. CoDesign, 1(2), 119-149. Doi: 10.1080/15710880500135987 Zikmund-Fisher, B. J. (2012). The Right Tool Is What They Need, Not What We Have: A Taxonomy of Appropriate Levels of Precision in Patient Risk Communication. Medical Care Research and Review, 70(1_suppl), 37S-49S. Doi: 10.1177/1077558712458541