This is one of the first studies to describe the knowledge of and intention to participate in cancer clinical trials among low acculturated, immigrant Latinos. While only one half of the population knew what a clinical trial was, when explained, 65% indicated a willingness to participate in a trial. Our statistics are slightly higher than the Wendler et al.(14)
study which indicated that 56% of Latinos are willing to participate in clinical trials when offered accurate information. We found that several information channels, including the Internet and telephone call centers appear to be effective in conveying information about clinical trials. While providers were cited as the most common source of health information, provider information was not associated with clinical trial knowledge or intent to participate in trials. Finally, psychosocial but not demographic factors were related to intent to join a cancer clinical trial.
This population had a higher than expected rate of Internet use, with 41% reporting access and 78% of these individuals reporting use of Spanish-language Internet sites for health information. Nationally, the Pew Hispanic Center Internet Project reports that 56% of Latinos use the Internet, compared to 71% of non-Hispanic Whites and 60% of non-Hispanic Blacks. (15)
In our sample those using the Internet for health information were more likely to know about clinical trials, and that knowledge, was in turn, associated with intent to participate in a clinical trial. Thus, despite slightly lower use than other ethnic groups, (15), (16)
Spanish-language Internet sites have the potential to reach a large number of Latinos about cancer clinical trials. A study with Latinos has suggested that the internet has proven to be a valuable source for health information and health care decision-making (17)
Use of a national information channel such as the National Cancer Institute’s (NCI) Cancer Information Service (CIS) was very low (4%) in this Latino population, even through services are available in Spanish. However, we did find that contact with the CIS Spanish-call lines was significantly associated with intent to participate in clinical trials. Given the cross-sectional nature of our study, we cannot determine if information imparted by the CIS resulted in interest in clinical trials, or if those who were motivated to join trials were more likely to call CIS. However, even under the latter scenario, it appears that CIS may have provided sufficient information to reinforce the intention to join a clinical trial. The CIS has been a valuable source for health information regarding up-to date information regarding cancer and clinical trials (18), (19),
. In addition, NCI has invested more in health education, including use of lay and professional educators at health fairs and other community outreach venues. We found that individuals who attended health fairs were more likely to report a willingness to enroll in clinical trial than those who did not receive health information in this setting. Therefore, it is possible that community-based health fairs could be used to convey clinical trial information, especially for prevention and screening trials since these events attract largely non-cancer populations.
Physicians are also a critical source of health information and strong motivators of general cancer-related behaviors in Latino and other ethnic minority populations (21), (22), (23), (24), (25), (26)
. In our study, providers were cited as the primary source of health information yet this information source was not
associated with clinical trial knowledge or intent to participate in a trial. This was particularly surprising since our survey was conducted in health care settings. This apparent paradox may have several explanations. Many of the safety net clinics participating in our study rely on volunteer providers. It is possible that these volunteers are too busy to provide cancer health education, since the volume of patients requesting care exceeds capacity in these safety-net clinics. Another explanation for the lack of association between provider information and trial knowledge and interest is that trials are not easily available or offered via safety net clinics. In addition, given the pressing acute health care needs of safety net clinic populations, discussion of clinical trials may not be especially salient. Since Latino providers are considered respected leaders in the Latino community (27), (28)
and were considered a trusted source of health information in our study, there may be a missed opportunity for providers to convey education about clinical trials. Further research is needed to better understand patient-provider communication about clinical trials and how to leverage the potential of the patient-physician relationship to convey cancer clinical trial information to Latinos across a variety of health care delivery systems.
Our results suggest that when Latinos know about RCTs, they are willing to participate. This is similar to the findings of Umatyan et al. (12)
giving credence to the importance of clinical trial awareness prior to participation. The null results for associations between demographic factors and intent to participate in trials may further indicate that media or other information campaigns may not have to be tailored to these characteristics. However, it is possible that we obtained null results because our population was fairly homogenous with respect to demographic characteristics; these competing hypotheses will be important to test in future research with more heterogeneous Latino sub-groups from broader settings.
Our findings do suggest, however, that psychosocial factors have the potential for use in interventions. For instance, those with high trust in health information had higher odds of knowing about and being willing to participate in clinical trials. The fact that our population was receiving care in safety net Latino-focused clinics with bilingual staff may have increased their trust of health information. (21), (24)
If this is confirmed in future research, messages about trials could be linked to trusted information sources like clinics and/or include content that enhance their credibility in the Latino population.(20)
Likewise, enhancing self-efficacy in obtaining trial information or tapping into perceived cancer risk could also be used to leverage interest in clinical trial participation. Other studies have shown that increased self-efficacy plays a role in a variety of behaviors (25), (26), (28)
There are some limitations that should be considered when evaluating our results, including the cross-sectional and quota design, external generalizability, and measurement issues. Due to the cross-sectional nature of this study, we can only estimate associations between variables of interest and clinical trial knowledge. Prospective studies will be important to determine directionality of the results we observed. We employed a quota sampling scheme so that we cannot calculate true clinic-wide prevalence rates. Our sample was a fairly homogenous immigrant, mono-lingual Latinos group from Central and South America who relied on safety net clinics for their care and as such, cannot be generalized to other Central and South American groups or other Latino populations. We used perceived risk measures and did not have data on actual cancer risk. Thus, the perceived risk measures require further investigation. Our measure of knowledge was based on only one question, although this question has been shown to relate to willingness to participate in trials in an earlier study in this same setting (30)
Finally, we do not know how intention to participate in a trial relates to actual behavior, since there were no trials available to offer this population at the time of the study. This will be a critical link to establish prior to developing and testing interventions to increase trial enrollment.
Overall, this study fills an important gap in our knowledge about clinical trial information needs and intentions in the growing Latino immigrant population. Since cancer is the second leading cause of death in this group, it is important that they are represented in clinical trials of cancer-related interventions to ensure generalizability of results and that this group benefits equitably from advances in cancer scientific knowledge and discovery.