# Background Prostate-specific antigen (PSA) testing is a common method for the early detection of prostate cancer. The test measures the level of PSA, a protein produced by the prostate, in the blood. Elevated PSA levels can indicate the presence of prostate cancer but can also result from other conditions such as prostatitis, benign prostatic hyperplasia, or even recent physical activities like cycling. While PSA testing can detect cancer early, potentially improving outcomes by enabling early treatment, it is also associated with significant risks and limitations. One of the primary benefits of PSA screening is its potential to reduce the mortality rate from prostate cancer. Studies suggest that PSA testing can prevent approximately three out of every thousand men from dying of prostate cancer. However, the test is not without its drawbacks. The specificity and sensitivity of the PSA test are not optimal, leading to a high rate of false positives. This can result in unnecessary anxiety, biopsies, and treatments for many men. For instance, out of 1000 men undergoing PSA screening, around 380 may receive an elevated PSA result, but only about 130 will actually have cancer. This means a significant number of men are exposed to unnecessary diagnostic procedures and treatments, which can have side effects such as incontinence and erectile dysfunction. The issue of overdiagnosis is particularly concerning. Prostate cancer often progresses very slowly, and many detected cases might not have caused symptoms or affected life expectancy if left undiagnosed. Overdiagnosis can lead to overtreatment, where men undergo treatments for cancers that would not have become clinically significant. This aspect raises ethical concerns about the balance between the benefits of potentially life-saving treatment and the harms of unnecessary medical intervention. The decision to undergo PSA screening is influenced by various factors. These include demographic variables such as age and family history of prostate cancer, personal and cultural beliefs, level of knowledge about the test and its implications, and psychosocial factors like fear of cancer, perceived risk, and influence from healthcare providers or peers. For instance, men with a family history of prostate cancer or those experiencing anxiety about their health are more likely to participate in regular screening. Conversely, concerns about the side effects of treatment, distrust in the healthcare system, or a belief that the test is unnecessary at an older age can deter men from undergoing PSA screening. Despite the controversies surrounding PSA screening, it remains a recommended practice by several health organizations, albeit with varying guidelines on the age and frequency of testing. The American Urologic Association, for example, suggests screening up to age 76, aligning with findings that competing mortality risks eventually outweigh the benefits of screening at older ages. In summary, PSA testing for prostate cancer involves a complex interplay of potential benefits and harms. This study seeks to delve into the preferences and decision-making processes of men regarding PSA screening, providing insights into the psychosocial and informational factors that influence their choices. This understanding can aid in developing better communication strategies and decision aids, ensuring that men make informed choices about their health. # Preference Epidemiology as a Method Preference epidemiology is an emerging field that integrates individuals' preferences and values into epidemiological research. This approach is particularly relevant in the context of medical decisions that involve significant trade-offs between benefits and harms, as is the case with prostate-specific antigen (PSA) screening for prostate cancer. Traditional epidemiology focuses on quantifying the risks and benefits of medical interventions using population-level data. In contrast, preference epidemiology emphasizes understanding the diverse perspectives and values of individuals, which can vary widely based on cultural, psychosocial, and informational factors. ## Ethical Considerations Incorporating preference epidemiology into public health research and policy-making may bring several ethical benefits. It ensures that health interventions are not only scientifically justified but also aligned with the values and preferences of the target population. This is particularly important in preventive health measures like PSA screening, where the decision to screen involves weighing the benefits of early cancer detection against the risks of overdiagnosis and overtreatment. By capturing the nuanced preferences of individuals, preference epidemiology respects patient autonomy and supports informed decision-making, which are core ethical principles in healthcare. Moreover, this approach acknowledges and addresses the variability in individual preferences that may be influenced by factors such as age, cultural background, health literacy, and personal experiences with healthcare. It helps identify groups with specific concerns or values that might not be adequately represented in traditional epidemiological studies. This inclusivity ensures that public health policies are more equitable and responsive to the needs of diverse populations, reducing health disparities. However, it is essential to distinguish between descriptive and prescriptive or normative ethics when considering preference epidemiology. Descriptive ethics involves understanding what people believe and how they behave, while prescriptive or normative ethics concerns what people ought to do. The preferences and opinions of the population, as revealed through preference epidemiology, do not inherently establish what is morally right or wrong. The opinion of the majority is not necessarily a source of moral normativity; it simply reflects what most people think or desire. While this data is crucial for understanding public sentiments and ensuring that health interventions are culturally sensitive and acceptable, it must be carefully weighed against ethical principles such as justice, autonomy, beneficence, and non-maleficence. Policymakers must ensure that the design and implementation of public health interventions are not solely driven by popular opinion but are also grounded in ethical reasoning that considers the well-being of all individuals, including vulnerable populations who may not have a strong voice in expressing their preferences. ## Relevance to Public Health Policy In the context of public health policy, preference epidemiology can provide valuable insights that can enhance the design and implementation of health interventions. For example, understanding the reasons why certain demographics may be less inclined to participate in PSA screening can inform targeted education and outreach efforts. It can also help policymakers design decision aids that better communicate the risks and benefits of screening, tailored to different levels of health literacy and cultural contexts. Evidence from preference epidemiology can guide the allocation of healthcare resources more efficiently by prioritizing interventions that align with public values. This approach can also reveal potential ethical dilemmas or public resistance to certain policies, allowing for more transparent and inclusive decision-making processes. For instance, if a significant portion of the population is concerned about the risks of overdiagnosis associated with PSA screening, this insight can prompt policymakers to invest in improved diagnostic technologies or alternative screening methods that mitigate these concerns. ## Evidence and Application Research in preference epidemiology can employ methods such as discrete choice experiments, conjoint analysis, and surveys to quantify how individuals value different aspects of healthcare interventions. In the case of PSA screening, studies might explore how much weight individuals place on factors like the reduction of cancer mortality, the risk of overdiagnosis, the potential side effects of treatments, and the psychological impact of a cancer diagnosis. These methods can provide quantitative data that offer a more comprehensive understanding of the potential impact of public health interventions. By integrating preference epidemiology into the study of PSA screening, this research can inform more person-centered guidelines and policies. For example, public health campaigns can be tailored to emphasize the aspects of screening most valued by the target audience, such as the peace of mind provided by knowing one's cancer risk or the potential to avoid unnecessary treatments. Conversely, a preference epidemiology approach might also reveal a significant portion of the population that prioritizes avoiding the anxiety and potential harm associated with false positives and overtreatment. This insight could lead to public health guidelines that recommend against routine PSA screening for low-risk groups, aligning with individuals' preferences to avoid unnecessary medical interventions and associated burdens. Additionally, the data can support the development of decision aids that help men make informed choices based on their personal values and circumstances, providing a balanced view that respects both the desire for proactive health management and the concerns about the risks of overdiagnosis and overtreatment. In summary, preference epidemiology can enhance the relevance and effectiveness of public health policies by ensuring they are not only evidence-based, but also that they keep in account the values and preferences of the population. This study specifically aims to provide a nuanced understanding of decision-making processes and perceptions of what constitutes an (non-)acceptable burden, which is crucial for interventions like PSA screening where the benefits and harms must be carefully balanced. Incorporating this approach into public health research and policy can lead to more ethical, inclusive, and responsive healthcare systems. # Ethics clearance The study has received ethics clearance from the University of Zurich's Faculty of Medicine Ethics Committee. The ethical review process ensured that the study adheres to the highest standards of ethical conduct, particularly in terms of participant consent, data protection, and the handling of sensitive information. The approval reference number for this project is 2024-255652.