Increasing the adoption of health behaviors at a population level is essential if we are to significantly decrease the burden of preventable cancer and improve public health. In the United States, more than 600,000 people die of cancer each year [1]. Approximately 30% of these deaths are linked to poor diet, physical inactivity, and carrying too much weight, with another 30% due to tobacco use, comprising nearly two-thirds of US cancer deaths [2-5]. Furthermore, cancer disproportionately impacts non-Hispanic Black populations largely due to inequities stemming from structural racism [6-9]. Evidence suggests that current primary care services do not effectively engage all patients in cancer prevention [10-16]. Therefore, there remains a need for other potential interventions to address this gap, especially among those most at risk.

One strategy to increase cancer prevention health behaviors is goal setting [17,18]. Collaborative goal setting, a process whereby the provider and patient agree upon a health-related specific SMART (specific, measurable, achievable, realistic, and time-bound) goal and action plan [19], has been shown to modify behaviors by directing intention and building self-efficacy [20-22]. However, in primary care, we lack an approach to implement a strategy for collaborative goal setting. A second approach to increase cancer prevention health behaviors is to disseminate health behaviors and knowledge through social networks, which are known to influence behaviors related to cancer risk, such as obesity and smoking [23-26]. Experimental studies suggest that reinforcement from multiple social ties (ie, through a network) increases health behavior adoption more than social reinforcements from single ties [27]. Prior work also suggests that cancer prevention strategies involving some form of social support are more effective in changing behaviors in BIPOC (Black, Indigenous, and People of Color) populations as compared with non-Hispanic White people [28,29]. There is evidence that BIPOC populations have denser social networks, with more reliable and frequent activation of informal social support [12,14].

The objective of this study is to develop and evaluate the content, usability, and acceptability of an electronic decision support tool—ie, a mobile app—that leverages these insights to facilitate cancer prevention goal setting, tracking, and sharing between primary care patients and their social ties. We conducted a series of semistructured interviews to determine the optimal content and app features before piloting the prototype with our priority population: non-Hispanic Black primary care patients. Although non-Hispanic Black populations use health technology at greater rates than their White counterparts [30-32], they remain underrepresented in studies about health technology and health behaviors [33,34]. There is evidence that end user experiences may vary by background and culture with the need for culturally sensitive and effective design [35-37]. In addition, there is a call for evaluating public health interventions with messaging grounded in the understanding of the populations served and without White bias [38,39].

Given that this app will center on facilitating cancer prevention behaviors in populations most at risk, we aimed to ensure the app is culturally attuned to and meets the needs of its targeted end user. We also aimed to test features, such as leveraging social ties, given the evidence that such features may work better among non-Hispanic Black populations [28,29]. Therefore, this study aims to evaluate the content, usability, and acceptability of a cancer prevention app designed with direct input from and specifically for a non-Hispanic Black primary care patient population.

We conducted a multistage, mixed methods study to develop and evaluate the content, usability, and acceptability of a mobile app that facilitates cancer prevention goal setting, goal tracking, and goal sharing. Consistent with mHealth app development best practices [40], this study comprised 2 stages. First, we obtained feedback from potential end users regarding the paper prototypes of the app. Then, we solicited feedback on a beta version of the app, informed by initial feedback, from a new set of participants. Participants completed questionnaires containing both open- and closed-ended questions, which were subsequently analyzed to refine the prototype. The study team guided the design, features, and content of both the paper prototype and the electronic beta version of the mobile app in collaboration with Transmogrify (Conshohocken, PA), a firm that helps create, build, and grow digital products. Figure 1 shows a visual representation of the study design and stages.

Of the 33 non-Hispanic Black primary care patients participating in the study, the mean age was 49 (SD 13) years, and 26 (79%) identified as female. Of the initial stage 1 (n=16) participants, 14 (88%) reported using a smartphone multiple times a day, 7 (44%) specifically used an app or digital fitness tracker to track their health, 13 (81%) reported tracking their health either digitally or manually, 15 (94%) reported sharing “some” or “a lot” of health information with close friends and family, and 13 (81%) said they have relied on friends to accomplish health goals. Only 25% (4/16) of the participants reported that they were comfortable discussing health matters on the internet.

Table 1 summarizes the 3 dominant themes and associated subthemes that emerged from the qualitative content analysis of both stages. Below, we expand on these qualitative themes and add additional insights and changes made during the iterative analysis.

We conducted 2 stages of semistructured interviews with non-Hispanic Black primary care patients to develop and iteratively refine a cancer prevention goal setting mobile app. Our study yielded three primary generalizable insights from our target population: (1) the framing of each goal and its relevance to cancer impacted the likelihood that the goal would be chosen, (2) participants thought that sharing health goals with others facilitates the adoption of healthy behaviors, and (3) most participants found it motivating to see other users’ goal progress, while still collaborating with these users on their health goals. An overarching insight that emerged across themes was the participants’ desire to customize and personalize the app.

Our first theme highlights the importance of framing goals as relevant to cancer prevention. Some participants in our study initially struggled to understand the connection between cancer and lifestyle behaviors, remarking instead that they felt as though “genes” and “God’s will” had a larger role to play. Nonetheless, we maintained the overall cancer prevention framework of the app, as health behavior research has demonstrated that framing behaviors as cancer preventing increases their adoption [54-56]. Moreover, a 2019 meta-analysis found that underserved populations in the United States are comfortable receiving cancer prevention information and interventions on the internet and through mobile devices [57]. In response to the feedback received, we clarified the language on the app to better communicate how changes in behavior can make a difference in cancer risk. We re-enforced this message with links to the ACS lay resources. Following these changes, participants in subsequent rounds did not convey similar confusion, and in fact, many appreciated the link between health behavior and cancer prevention. This change is one example of the numerous adaptations we made to optimize the app for the intended end users.

The second and third themes indicate the values of goal sharing and collaboration, respectively. Although some participants hoped that the app would foster competition among users for completing health goals, most expressed a strong desire for the app to facilitate collaboration with others to achieve their health goals. This tension between competition and collaboration is frequently studied in behavioral economics, with mixed evidence as to which approach yields a greater impact on health behavior [58]. To respect the diverging opinions among our participants, we created a progress board that displays each user’s goal success count, allowing more competitive-minded users a chance to compare their progress to others. We removed any references to “leaderboards” and added new avenues for participants to communicate with each other on the app, responding to most participants who expressed a desire to collaborate with other app users. Brewer et al [59] similarly found a “sharing board” to be a popular feature in their app promoting cardiovascular health among church-going African Americans. Participants in Brewer’s study were likewise motivated by the ability to send and receive encouraging messages while keeping track of other users’ progress.

Finally, we found that participants uniformly valued the ability to customize the app to meet their unique needs, and in response, we provided additional options for goal sharing and goal setting. The desire for customization is common in health app development [60,61], and we aimed to satisfy participant requests while ensuring that the app remained grounded in evidence-based techniques. For example, although we allowed participants to modify the frequency of a particular health goal (eg, dance for 30 minutes three vs four times a week), we did not allow users to write their own health goals. We made this choice to ensure that all of our goals remained consistent with ACS recommendations and an evidence-based SMART [19] set-up.

Given that this study evaluated end user experience with a mobile app exclusively among a non-Hispanic Black population, it is difficult to ascertain whether our findings are unique to this population or perhaps more broadly applicable to other populations. However, we did find a preference for collaboration over competition that aligns with prior evidence of this among non-Hispanic Black populations [59]. In addition, our findings of fatalism in early iterations of app content feedback aligned with prior studies that demonstrate this among non-Hispanic Black populations [62-64]. Future studies should be designed to compare the experiences of apps and messaging between users to determine what features may be uniquely appreciated by one racial/ethnic population as compared with another.

These findings must be considered in the context of several limitations and strengths. First, the study used a nonprobabilistic purposive sampling technique to recruit non-Hispanic black primary care patients from 2 primary care clinics and thus may not be generalizable. Second, we recognize that stated intentions do not always align with future behavior, and we cannot predict the effectiveness of this tool based on this study. The objective of this study is to develop and optimize the features and content of the app with and for our target population. This methodology also has several strengths. In contrast to many other behavior change apps [65], we followed a user-centered design approach to optimize the app for our intended audience, which may have different content wishes than other populations [57,66,67]. We also followed app design best practices by conducting iterative rounds of testing, allowing ample opportunities for usability feedback from potential end users [40,42]. Finally, 2 team members experienced in qualitative research analyzed all participant feedback using more traditional qualitative content analysis techniques to search for generalizable insights that may inform future health intervention research beyond the development of this app.

Cancer prevention in the modern era must include options that are accessible to all, but this does not mean that all options must be universal. A mobile app—or any intervention, importantly—that promotes healthy, cancer-preventing behaviors in population A is not guaranteed to work as well with population B. Accordingly, given the disproportionate burden of cancer and cancer-related mortality among non-Hispanic Black populations in the United States [6-9], our iterative development approach for a cancer prevention mobile app focused uniquely and specifically on goal setting among non-Hispanic Black primary care patients. This iterative process led to the development of a cancer prevention mobile app that potential end users deemed usable and acceptable and yielded noteworthy insights about what intended end users value in health goals and how they may work on these goals with others.