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. Author manuscript; available in PMC: 2020 Dec 1.
Published in final edited form as: West J Nurs Res. 2019 Feb 19;41(12):1747–1760. doi: 10.1177/0193945919829145

A national study of oncology nurses discussing cancer clinical trials with patients

Susan A Flocke 1, Nora L Nock 2, Sarah Fulton 3, Seunghee Margevicius 4, Sharon Manne 5, Neal J Meropol 6, Barbara J Daly 7
PMCID: PMC6699918  NIHMSID: NIHMS1029309  PMID: 30782111

Abstract

In the United States less than 10% of cancer patients engage in clinical trials. Although most oncology nurses have multiple opportunities to discuss clinical trials with patients, barriers including attitudes and social norms may impede these discussions. Guided by the Theory of Planned Behavior, we developed and evaluated measures for attitudes, subjective norms and perceived behavioral control of nurses for discussing clinical trials with cancer patients. Of the 18,000 Oncology Nurse Society members invited, 1,964 completed the survey. Structural equation modeling and internal consistency reliability were used to evaluate items and constructs. We found that overall model fit and reliability was good: Confirmatory Fit Index (CFI)=0.91, Root Mean Square Error of Approximation (RMSEA)=0.05; attitudes, 21 items, alpha=0.84; perceived behavioral control, 10 items, alpha=0.85; and subjective norms, 9 items, alpha=0.89. These measures of attitudes, subjective norms and perceived behavioral control show good reliability and initial evidence of validity.

Keywords: clinical trials, nurses, communication, measurement

Clinical trials provide the evidence base for clinical practice, however less than 10% of cancer patients participate (Al-Refaie et al., 2011; Institute of Medicine, 2010; Murthy, Krumholz, & Gross, 2004; Unger et al., 2013). Clinical trials may include evaluation of a new drug or treatment approach, but also can include studies about new cancer diagnostics, prevention, or supportive care interventions. Oncology nurses spend a substantial amount of time with patients and often develop relationships over time. This presents opportunities to raise patient awareness about the potential to participate in clinical trials. Specifically, oncology nurses are in a key position to engage patients and increase awareness and accurate understanding of clinical trials through patient education, counseling, and support for informed decision making (Jenerette & Mayer, 2016).

However, little is known about the degree to which oncology nurses discuss clinical trials with patients. Much of the literature is focused on the role of nurses as clinical trial coordinators (Hastings et al., 2012); much less is known about attitudes and behaviors of nurses who serve in traditional patient care roles. One study found that the vast majority of nurses believe that patient participation in clinical trials is important, but only about half thought that patients should be encouraged to participate (Burnett et al., 2001). Among nurse practitioners surveyed about cancer clinical trials, barriers include ethical concerns, lack of education about how to hold discussions, and discomfort discussing clinical trials with patients (Ulrich et al., 2012). Oncology nurse initiation of general discussions about clinical trials was not common, and barriers to such discussions include lack of knowledge, strategies for addressing common patient misconceptions, and uncertainty with regard to timing of discussions (Flocke et al., 2017). Further, nurses commonly define their roles as patient educators and advocates, which includes providing information, support, and assistance to the patient after an initial discussion about available trials had taken place (Flocke et al., 2017).

Oncology nurses have an opportunity to play a central role in assuring that patients are educated about the option of taking part in a clinical trial, have questions and concerns addressed, and receive support for making an informed decision. However, we lack data regarding the extent to which practicing nurses see this as part of their role, what their attitudes and beliefs are, and what challenges may exist to fulfilling these important responsibilities. Our prior work used qualitative interviews to begin to understand perceptions and attitudes towards initiating discussions of clinical trials. Understanding attitudes and perceptions from a broader sample of oncology nurses requires the development of valid and reliable measures. The Theory of Planned Behavior (TPB) provides a framework for understanding what directs intention and behavior. The TPB posits that attitudes toward the behavior, perceptions of behavior norms of key peers towards the behavior and perceived behavioral control (i.e., the extent to which an individual believes he/she can perform the behavior), are essential characteristics associated with performing a behavior (Ajzen, 1985; Ajzen & Fishbein, 1972; Armitage & Conner, 2001).

Purpose

Guided by the TPB, this study aimed to establish measures and to assess oncology nurses’ attitudes, subjective norms and perceived behavioral control (PBC) for discussing cancer clinical trials with patients.

Methods

Design

Data for this cross-sectional analysis are drawn from the baseline cohort of oncology nurses participating in a larger study of an educational intervention about clinical trials. Participants were drawn from the Oncology Nursing Society (ONS) active membership rolls and include a national sample of oncology nurses actively engaged in providing patient care.

Sampling frame and inclusion criteria

Invitations to participate were sent to all ONS members and included both a handwritten letter and an emailed invitation containing a link to a web-based survey. The web-link led to an introduction and an informed consent page. Individuals who completed the consent process were then directed to a web-based survey that included questions to assess eligibility, with the key inclusion criterion being currently engaged in direct patient care. Those who indicated that they were unemployed, retired, a clinical trials/research nurse, a nurse working for a pharmaceutical or device company, or a nurse working in a non-patient care setting were not eligible, and the survey ended at this screen. Eligible participants were asked to complete an online battery of instruments that included assessment of attitudes, perceived behavioral control, and social norms towards discussing clinical trials with patients.

Measures

Demographics included age, gender, degree(s) and work setting (e.g., community outpatient, radiation, etc.). Measures for the study were based on the Theory of Planned Behavior (Francis et al., 2004) and were adapted from prior studies assessing patient barriers to clinical trial accrual (Burnett et al., 2001; Meropol et al., 2007); and qualitative interviews with oncology nurses to more deeply understand how clinical trials are discussed in a range of clinical settings (Flocke et al., 2017). Three main concepts were measured: attitudes, perceived behavioral control and subjective norms. Item development was guided by “Constructing questionnaires based on the theory of planned behaviour: A manual for health services researchers” by Francis et al. (2004) which is highly prescriptive about item content, format and response format. Candidate items were evaluated by the multidisciplinary study team for content and clarity; two practicing nurses then reviewed the items for clarity, and finally items were pilot tested. The pilot test involved administering the survey items to 112 nurses. The goal of the pilot testing was to assess the general performance of items including readability, clarity of items of instructions and response formats for the item blocks, and to assess the range of responses.

Attitudes.

A total of 21 items were included to assess attitudes and all had a seven-point Likert response format of strongly disagree to strongly agree. Item content included attitudes about operational aspects (e.g., “Discussing information about clinical trials will fit within the time I have to complete my work”) and attitudes about the impact on patients (e.g., “Discussing clinical trials with patients may encourage them to go elsewhere for their care”). Items were summed to create an attitude score.

Subjective Norms.

Items designed to measure subjective norms used seven normative groups identified as relevant to oncology nurses: nurse managers, patients, physicians, work institution, other nurses at work, patients’ families, and professional organization. For each normative group two items were assessed as illustrated by the following example: “My nurse manager thinks I should talk about clinical trials with patients” (evaluated on a seven-point Likert scale, strongly disagree to strongly agree), and “Doing what my nurse manager think I should do is:” (scored on a seven-point scale: not at all important, of little importance, slightly important, of average importance, moderately important, very important and extremely important). In the evaluation of these items, we assess the degree to which the subjective norm items hang together as a latent variable and construct two summary scores. The first summary score is the total of the first set of 10 items, the second score is the sum of the product of the paired items (e.g., my nurse manager thinks I should talk about clinical trials with patients * doing what my nurse manager things I should do is…). High scores indicate a high level of subjective norms to engage in discussing clinical trials with patients.

Perceived Behavioral Control.

Assessment of perceived behavioral control included 10 items focused on confidence about discussing clinical trials with patients. Example items include “I feel confident that I can explain to patients how clinical trials generally work,” and “I know where to direct patients to find out more about clinical trials.” Additional items assessed perception of how difficult each action is (e.g., “Explaining to patients how clinical trials generally work is:”) with response options of difficult, moderately difficult, slightly difficult, neutral, slightly easy, moderately easy, easy. The 10 items about confidence were summed to create a total score. Six items to assess difficulty are scored and reported separately.

All data collection procedures for this study were approved by the Institutional Review Board of University Hospitals of Cleveland (protocol # 04–14-08C).

Analyses

Data analysis included descriptive statistics of participant characteristics. Internal consistency reliability was evaluated using Cronbach’s alpha, and a target of greater than 0.80 used as very good reliability. We used confirmatory factor analysis (CFA), which is a form of latent variable structural equation modeling, to evaluate the overall fit of our hypothesized measurement model. In this model, we allowed all factors/latent constructs to correlate freely and imposed no constraints on how the factors were related to each other, allowing for residual correlations between items that had substantive impact on model fit; however, we did not allow for cross loadings of items (i.e., loadings between items on different constructs). Specifically, we used a robust maximum likelihood estimator (MLR), which provides test statistics and standard errors robust to non-independence of observations and non-normality (Muthén & Muthén 2017), to formally test our CFA model. All P-values reported were from 2-sided tests, and statistical significance was set at ≤ 0.05. To assess the overall goodness-of-fit of the CFA model to the data, the comparative fit index (CFI), root mean square error of approximation (RMSEA), and standardized root mean square residual (SRMR) were evaluated (Kline, 2005). The χ2 test, which evaluates whether the covariance matrix is equal to the model-implied covariance matrix predicted by the parameters, is very sensitive to sample size and model complexity; thus, we used the CFI, RMSEA, and SRMR to evaluate overall model fit. Values for the CFI (which is relatively insensitive to sample size and model complexity) of 0.90– 0.95 are suggested to represent acceptable-to-good model fit, respectively (Hair, Black, Babin, Anderson, & Tatham, 2005; Hu & Bentler, 1999). RMSEA is an index that is less sensitive to sample size and favors more parsimonious models, and RMSEA values of 0.06 or less represent good model fit, whereas values exceeding 0.10 represent unacceptable fit (Hair et al., 2005; Hu & Bentler, 1999). For the SRMR, which accounts for differences in scale in computing residuals, values of 0.08 or less and less than 0.10 represent good and acceptable fit, respectively (Hu & Bentler, 1999; Kline, 2005).

Summary scores were computed by summing items for each construct and transforming to a T score (i.e., a mean of 50 and standard deviation of 10). For each measure, the mean, standard deviation, range are reported.

Results

Of the 18,000 individuals invited to participate in this study, 2,453 consented to the study and 1,964 were eligible and completed the survey. Descriptive characteristics of the baseline sample are reported in Table 1. The sample is predominately female and has a mean age of 45.6. Most (80.1%) have an education of a bachelor’s degree or higher. About one quarter provide patient care in an inpatient setting and 74.6% provide care in an outpatient setting. On average, participants have been in an oncology nurse role for 15.1 years (standard deviation of 9.9). Participants are similar in gender, age and degree to those that were invited and did not participate (data not shown).

Table 1.

Baseline Study Sample Characteristics (N=1964)

Characteristic   N (%)
Female 1912 (97.4%)
Race
 Caucasian 1707 (87.0)
 African-American    52 (2.7%)
 Asian  102 (5.2%)
 Other  100 (5.1%)
Highest Level of Education
 High School Diploma    89 (4.5%)
 Associate Degree  303 (15.4%)
 Bachelor’s Degree 1060 (54.0%)
 Master’s Degree  476 (24.3%)
 Doctoral (DNP or PhD)    35 (1.8%)
Primary Work Setting
 Out-Patient 1465 (74.6)
 In-Patient  499 (25.4%)
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The completion rate of the items to assess attitudes, perceived behavioral control and subjective norms was 99%. All response categories were used for each of the items, and the mean and standard deviation for each item are reported in Table 2.

Table 2.

IMPACT Measurement Model Constructs and Properties

TPB
Construct		 Items for each construct Mean ± SD Factor
loading1 ±
SE
Attitudes2
1. If I bring up clinical trials, patients will think their treatments are not working * 4.31 ± 1.58 0.66 ± 0.02
2. If I discuss clinical trials with patients, they will become upset * 5.33 ± 1.36 0.65 ± 0.02
3. If I bring up clinical trials, I may add to conflict that may exist between patients and their family members* 4.29 ± 1.46 0.60 ± 0.02
4. Discussing clinical trials with patients who have not exhausted all available standard therapies will result in worse health outcomes * 5.77 ± 1.35 0.59 ± 0.02
5. If I discuss clinical trials with patients, they will think they are being asked to be “guinea pigs” * 4.62 ± 1.60 0.56 ± 0.02
6. Discussing clinical trials with patients may encourage them to go elsewhere for care* 5.26 ± 1.48 0.54 ± 0.02
7. Discussing clinical trials with patients will introduce them to riskier treatment options * 5.42 ± 1.43 0.53 ± 0.02
8. I am discouraged from discussing clinical trials because the patient might seek care elsewhere * 6.03 ± 1.26 0.53 ± 0.02
9. If I discuss clinical trials with patients, I will get some of the facts wrong * 4.47 ± 1.65 0.52 ± 0.02
10. My interactions with patients are too limited to feel comfortable discussing clinical trials with them * 4.88 ± 1.80 0.51 ± 0.02
11. If I bring up clinical trials, patients will think I want them to participate * 3.93 ± 1.48 0.45 ± 0.02
12. Discussing information about clinical trials will give some patients unrealistic hope * 5.04 ± 1.56 0.44 ± 0.02
13. Clinical trials are too burdensome for patients * 4.64 ± 1.39 0.43 ± 0.02
14. Clinical trials are good for the patients who participate 4.92 ± 1.16 0.37 ± 0.02
15. Discussing clinical trials with patients will ease their concerns about having a computer choose their treatment instead of a doctor 4.21 ± 1.45 0.36 ± 0.03
16. Discussing clinical trials with patients will encourage more of them to participate 5.12 ± 1/34 0.35 ± 0.03
17. Discussing information about clinical trials will help patients ask the physician questions 5.61 ± 1.30 0.30 ± 0.03
18. If I discuss clinical trials with patients, I am doing something positive for them 3 5.17 ± 1.95 0.26 ± 0.02
19. I am concerned clinical trials are too expensive for patient * 4.85 ± 1.62 0.26 ± 0.02
20. Discussing information about clinical trials will fit in the time I have to compete my work 3.97 ± 1.69 0.25 ± 0.03
21. If I discuss clinical trials with patients, it will ease their concerns about getting placebo 4.23 ± 1.57 0.24 ± 0.03
Subjective Norms
1. Other nurses I work with think I should discuss clinical trials with patients 3.32 ± 1.89 0.85 ± 0.01
2. My institution encourages me to present basic information about clinical trials 3.85 ± 2.09 0.83 ± 0.01
3. My nurse managers think I should talk about clinical trials with patients 3.38 ± 1.90 0.74 ± 0.01
4. Patients’ families think I should provide patients with information about clinical trials 3.48 ± 1.67 0.72 ± 0.01
5. My professional organization(s) encourages me to discuss clinical trials with patients 4.53 ± 1.94 0.67 ± 0.01
6. Patients think I should provide them information about clinical trials 3.57 ± 1.74 0.66 ± 0.02
7. The physicians with whom I work would approve of my discussing clinical trials with patients 4.90 ± 1.80 0.60 ± 0.02
8. I am expected to discuss clinical trials with patients 2.81 ± 1.97 0.44 ± 0.14
Perceived Behavioral Control
1. For me, talking about clinical trials is *different response format* 3.98 ± 1.75 0.75 ± 0.01
2. I feel confident that I can explain to patient how clinical trials generally work 4.37 ± 1.91 0.74 ± 0.01
3. I have access to general patient education materials about clinical trials to provide to patients 4.09 ± 2.11 0.65 ± 0.02
4. I feel confident that I can let the medical team know what the patient thinks about taking part in clinical trials 5.28 ± 1.63 0.64 ± 0.02
5. It is a standard part of the nurse’s role to talk to patients about clinical trials 3.72 ± 1.85 0.64 ± 0.02
6. I know where to direct patient to find out more about clinical trials 5.22 ± 1.93 0.54 ± 0.02
7. It is part of my role to support patients to make an informed decision about participating in clinical trials 5.08 ± 1.91 0.53 ± 0.02
8. I have the time to talk to patients about clinical trials 4.05 ± 1.79 0.48 ± 0.02
9. I am confident that I can discuss clinical trials with patients if I want to 4.65 ± 1.94 0.38 ± 0.14
10. Whether or not I discuss clinical trials with patients is entirely up to me 4.60 ± 1.87 0.20 ± 0.03
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1

Standardized factor loading in SEM model; all p-values <0.01

2

Summary statistics for each scale: Attitudes, 21 items, mean=50 std dev=10, range 11–79, internal consistency =0.84; Subjective norms, 7 items, mean=50 std dev=10, range 27–72, internal consistency =0.89; Perceived behavioral control, 10 items, mean=50 std dev=10, range 23–78, internal consistency =0.85.

*

Item reverse scored

The hypothesized underlying measurement model of attitudes, perceived behavioral control and subjective norms constructs had good overall model fit (CFI=0.91; RMSEA=0.048 (95% CI: 0.046–0.049); SRMR=0.06). The standardized factor loadings (Table 2) for all items on their respective constructs were highly significant (p<0.001). The magnitude and significance of the standardized factor loadings can be used to help evaluate the strength of the relationship between the observed item and the underlying factor. For attitudes, perceived behavioral control and subjective norms, items are displayed in descending order of the standardized factor loading on their respective construct; loadings ranged from 0.20 to 0.85. In the CFA model, we allowed the three constructs to freely vary and included residual correlations between items that had substantive impact on model fit (e.g., between Attitude Item 12 and Attitude Item 13; between Subjective Norm Item 4 and Subjective Norm Item 8). Correlations between constructs ranged from r=0.45 to 0.78 with all p<0.001 (Subjective Norms and Attitudes: 0.45 ± 0.03; Subjective Norms and Perceived Behavioral Control: 0.78 ± 0.01; Perceived Behavioral Control and Attitudes: 0.65 ± 0.02).

Summary statistics for computed scores and descriptive statistics for each item contributing to each construct are presented in Table 2. Overall, the internal consistency reliability for each of the measures was excellent and ranged from 0.80 to 0.89. Most of the summary T scores range from −2 to +2 standard deviations from the mean, indicating a good spread.

Discussion

Clinical trials serve an important purpose, informing the effectiveness of treatments and intervention strategies, with the ultimate goal of building evidence to guide clinical practice towards improved care and outcomes. However, even among patients who are eligible, very few participate in a clinical trial. (Hastings et al., 2012; Haugen et al., 2016; Ocker & Plank, 2000; Spilsbury et al., 2008; Sun & Borneman, 2007). Ensuring that all patients have access to trials is a high priority. Multiple strategies of reaching patients have been proposed including patient education and outreach (Treweek et al., 2018) and recruiter communication strategies (Mills et al., 2018; Townsend, Mills, Savovic, & Donovan, 2015). However, given the amount of contact and public trust that nurses have, nurses can play a substantial role to increase the number of patients that have an opportunity to participate in clinical trials. This study substantially adds to the literature about oncology nurse attitudes and norms of discussing clinical trials with patients by providing measures that have good psychometric properties and reporting the distribution of scores across a national sample of oncology nurses.

The measures developed for this study are rooted in theory and informed from formative qualitative work to highlight the issues of relevance to discussing clinical trials by oncology nurses in a variety of care settings. This study indicates that the brief measures can reliably assess oncology nurse attitudes, subjective norms and perceived behavioral control towards discussing clinical trials with patients. The majority of items meet evaluation criteria and substantially contribute to the validity and internal consistency reliability of the measures. Specifically, the observed pattern of loadings of items designed to measure each latent construct provides some evidence of construct validity. The measures also show good spread of scores across this diverse pool of study participants indicating that these measures have good potential to co-vary with other characteristics that could help to further establish the validity of the measures. Overall, the internal consistency of the measures was very good, even for the measure of subjective norms which only included seven items. Given the large number of items and very high internal consistency, the measure of attitudes maintains an internal consistency reliability of 0.80 with as few as 10 items. Overall, these measures could be used in other settings and could serve as the basis for assessing attitudes and behaviors to inform training needs, to assess the impact of training or to compare groups with different backgrounds and training in addressing clinical trials.

The ability to reliably measure these constructs provides the basis for developing and implementing programs and trainings to go beyond knowledge of aspects of clinical trials and moves towards the factors that facilitate and support behavior change. In this national sample, we observe wide ranging scores on these constructs that are important to supporting the behavior of discussing clinical trials with patients. We know from a vast amount of literature on behavior change that knowledge is not sufficient; belief that the behavior is important and that it is one’s role, that other social normative groups are in support, and self-efficacy and confidence to do the behavior are critical components to initiating and sustaining behavior change.

While this study has many strengths including the large national sample, items rooted in theory and qualitative formative work, a few limitations are noteworthy. The primary limitation is the low response rate to the invitation to participate in the study. The findings in this report are drawn from the baseline data collection effort of a large randomized control trial and multiple points of data collection. Thus, participation involved approximately two hours of time for which individuals received continuing education credits as an incentive. Analysis of the characteristics of participants vs. non-participants show no differences in gender, age and education. The participant rate is similar to prior studies conducted by ONS (Personal communication, Marc Irwin). It is possible that individuals with greater interest, knowledge and experience with discussing clinical trials were more likely to participate in this study. Given that the measures already have a wide distribution of scores, we would not expect the rate of participation to influence the observed measurement properties. The work of this study is a good first step toward establishing measures of nurse attitudes, subjective norms and perceived behavioral control; these measures could be used in a variety of research and quality improvement contexts. However, additional evaluation is desirable; specifically, the measurement property of responsiveness was not assessed as part of this study. Responsiveness is a property of a measure that reflects change in scores when the individual’s level of the underlying construct changes. For example, one would expect that participation in an evidence-based intervention to increase oncology nurses’ perceived behavioral control to discuss clinical trials will result in increased perceived behavioral control scores vs. no change in scores for individuals exposed to an attention control intervention. In summary, the measures presented in this study are reliable, have initial evidence of validity and have good potential for utility as there is wide variability in scores on the measures across this national sample. An ongoing study is using these measures to test the value of a tailored video-based educational intervention designed to increase oncology nurse intention to discuss clinical trials with patients.

Acknowledgements:

Research reported in this publication was supported by the National Cancer Institute of the National Institutes of Health under Award Number R25CA177574 (Meropol, Daly). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Footnotes

Research Ethics: Trial registration number and trial register: NCT02129517

Conflicts of Interests: The authors declare no conflict of interests.

Contributor Information

Susan A. Flocke, Department of Family Medicine, Oregon Health & Science University, Portland OR

Nora L. Nock, Department of Population & Quantitative Health Sciences, Case Western Reserve University, Cleveland OH

Sarah Fulton, Begun Center for Violence Prevention Research and Education Case Western Reserve University.

Seunghee Margevicius, Department of Population & Quantitative Health Sciences, Case Western Reserve University, Cleveland OH.

Sharon Manne, Department of Medicine, Rutgers, New Brunswick, NJ.

Neal J. Meropol, Flatiron Health, New York, NY; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH

Barbara J. Daly, School of Nursing, Case Western Reserve University, Cleveland Ohio

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