Barriers to participation in cancer prevention clinical trials

Figures & data

Table I. First-degree relative perceived and practical barriers to participation in cancer prevention clinical trials subscale items and Cronbach's alphas.

Information Sources Scale Items	α=.89
I would be interested in participating in a cancer prevention clinical trial that:
I heard about on the news
I learned about on the internet.
A family member told me about.
My doctor told me about.
My relative's cancer doctor told me about.
Preferences for Prevention Approaches Scale Items	α=.92
I would be interested in participating in a cancer prevention clinical trial if:
I had to take vitamins or minerals.
I had to follow a specific diet or exercise program.
It involved complementary or alternative medicine approaches.
I had to take a prescribed medicine by mouth daily.
I had to take an injection in my arm for only three months.
I had to take an injection in my arm each week.
I had to take an injection in my arm each month for the rest of my life.
Psychosocial Factors Scale Items	α = .79
Learning about cancer prevention clinical trials would make me worry about getting cancer.
The thought of participating in clinical research makes me hopeful.
I feel hopeful when I think about how a cancer prevention trial might benefit me in particular.
I find it stressful to think about getting an experimental or investigational treatment.
I would be able to handle the requirements of taking part in a cancer prevention clinical trial.
I believe that participating in a cancer prevention clinical trial:
Would harm me.
Is important to find ways to prevent cancer.
Would benefit me.
Would benefit others.
I believe that:
I would get good care if I participated in a cancer prevention clinical trial.
Taking part in a cancer prevention clinical trial would decrease my risk of getting cancer.
I would get a placebo (sugar pill) if I participated in a clinical trial.
I would be likely to experience side effects if I took part in a cancer prevention clinical trial.

Abbreviations: α=Cronbach's alpha.

Figure 1. Reasons why oncologists do not participate in clinical prevention trials. (N=126) (p < 0.001)^a.

Table II. Oncologist demographic and practice characteristics (n=137)

Demographic	Frequency	Percentage
Age (years)	Median 49	Min 32	Max 71
Sex
Male	111	81%
Female	26	19%
Ethnicity
Hispanic or Latino	1	1%
Non-Hispanic or Latino	134	99%
Race
White	118	86%
Asian	14	10%
African American or Black	2	1.5%
Native American/Pacific	2	1.5%
Islander
Unknown	1	1%
Professional Setting
Private practice or community/other hospital-based	85	62%
Academic Medical Center	52	38%
Board certified:
Medical Oncology	124	91%
Hematology	80	59%
Practice^a	Median	Quartiles
Oncology patients seen in the past year	700	400,2000
New oncology patients in past year	200	100,300
Patients on cancer prevention clinical trials	0	0,10
Active prevention clinical trials	2	2,5

Abbreviations: Min, minimum; Max, maximum.

^aIncludes all oncology patients in each provider practice.

Table III. First-degree relative background and demographic characteristics (n=82)

	Frequency	Percentage
Age (years)	Median 46	Min 18	Max 83
Gender
Male	23	28%
Female	59	72%
Ethnicity
No response	7	9%
Non-Hispanic or Latino	75	91%
Race
White	73	89%
Non-white	9	11%
Education
High School or Below	31	38%
Above High School	51	62%
Marital
Married	48	59%
Not Married	33	40%
No response	1	1%
Employment
Working	63	77%
Not Working	19	23%
Income
<$30 000	34	42%
>$30 000	43	53%
No response	5	6%
Health Insurance
Yes	73	89%
No	8	10%
Relatives with Cancer
1	33	40%
2–3	36	44%
>3	13	16%
How often are you involved in the care of your relative: (the index patient)?
Never	14	17%
Rarely	17	21%
Monthly	13	16%
Weekly	18	22%
Daily	19	23%
No response	1	1%

Table IV. Association of cancer prevention clinical trial barrier subscale items to first-degree relative responses to: “I would participate in a cancer prevention clinical trial if it was offered to me.”

Cancer prevention clinical trial barrier subscales and subscale items	Agreement with the statement,“I would participate in a cancer prevention clinical trial if it was offered to me.” ^a
	Less willing to participate^b 37 (45%)	More willing to participate^b 45 (55%)	Total 82 (100%)	p
Information Sources
I would be interested in a cancer prevention clinical trial that:
My relatives cancer doctor told me about.	11/37 (30%)	31/44 (70%)	42/81 (52%)	<0.001
My doctor told me about.	10/37 (27%)	31/44 (70%)	41/81 (51%)	<0.001
A family member told me about.	4/37 (11%)	25/44 (57%)	29/81 (36%)	<0.001
I heard about on the news.	2/27 (5%)	13/44 (30%)	15/81 (19%)	0.026
I learned about on the Internet.	0/36 (0%)	8/44 (18%)	8/80 (10%)	0.025
Preferences for Prevention Approaches
I would be interested in a cancer prevention clinical trial even if:
I had to take vitamins or minerals.	12/37 (32%)	30/43 (70%)	42/80 (53%)	<0.001
I had to follow a special diet or exercise program.	12/37 (32%)	31/45 (69%)	43/82 (53%)	<0.001
It involved complementary/alternative medicine approaches.	9/37 (24%)	21/44 (48%)	30/81 (37%)	0.039
There was a chance of taking a placebo.	4/37 (11%)	25/43 (58%)	29/80 (37%)	<0.001
I might experience side effects from the treatment.	4/37 (11%)	16/43 (37%)	20/80 (25%)	0.035
I had to take a prescribed medicine by mouth daily.	2/36 (6%)	17/44 (39%)	19/80 (24%)	0.001
I had to take an injection in my arm for only three months.	2/37 (5%)	16/44 (36%)	18/81 (22%)	0.003
I had to take an injection in my arm each week.	1/37 (3%)	13/43 (30%)	14/80 (18%)	0.004
I had to take an injection in my arm monthly for the rest of life.	2/37 (5%)	12/44 (27%)	14/81 (17%)	0.042
Experimental treatments were riskier than standard approach.	2/36 (6%)	12/43 (28%)	14/79 (18%)	0.039
Psychosocial Factors
I believe that participating in cancer prevention clinical trials:
Is important to find ways to prevent cancer.	20/37 (54%)	41/45 (91%)	61/82 (74%)	<0.001
Would benefit others.	24/37 (65%)	39/43 (91%)	63/80 (79%)	0.009
Would benefit me.	9/37 (24%)	37/43 (86%)	46/80 (58%)	<0.001
Would decrease my risk of cancer.	3/37 (8%)	20/44 (45%)	23/80 (29%)	0.001
The thought of participating in clinical research makes me hopeful.	7/37 (19%)	25/44 (57%)	32/80 (40%)	0.003
I feel hopeful when I think about how a cancer prevention clinical trial might benefit me in particular.	12/37 (32%)	26/45 (58%)	38/82 (47%)	0.006
I would be able to handle the requirements of taking part in a cancer prevention clinical trial.	6/37 (17%)	31/44 (70%)	37/80 (46%)	<0.001
I [do not] believe that participating in a cancer prevention clinical trial would harm me.	24/37 (65%)	40/44 (91%)	64/80 (80%)	0.006

^aParticipants were asked to rate their agreement with statement. Five choices were offered in Likert fashion (Not at all, A little, Some, Moderately, and A lot). “Less willing to participate” includes those responding Not at all, A little, or Some, while “More willing to participate” includes those responding Moderately and A lot.

^bColumn percents for subscale items. Some denominators may be reduced due to non-response by participants.

Table V. Association of cancer prevention clinical trial barrier subscales and demographic factors to interest in first-degree relatives in participation in a cancer prevention clinical trial (n=60 complete data)^a

Variable	Odds Ratio	95% Confidence Interval
Information sources scale	3.36^b	(1.04, 10.84)
Preferences for prevention approaches scale	0.97^c	(0.38, 2.48)
Psychosocial factors scale	2.47^d	(1.15, 5.31)
Confounders
Sex (Female)	0.94	(0.25, 3.61)
Age	1.12	(0.90, 1.39)
Education (Some college)	0.96	(0.29, 3.17)
Married/partnered	2.55	(0.63, 10.36)
Number of relatives with cancer	1.27	(0.54, 3.00)
How often FDR is involved with care of patient	0.92	(0.59, 1.44)
Employed/seeking employment	0.20	(0.01, 3.29)

^aCumulative logistic regression slope estimates for 3-level ordinal variable: “I would participate in a cancer prevention clinical trial if it was offered to me.” ^bOdds ratio for individuals who are more information source responsive versus less. ^cOdds ratio for individuals who are less averse to treatments versus more. ^dOdds ratio for individuals who report fewer psychosocial barriers versus more

Figure 2. Reasons why FDRs do not participate in clinical prevention trials. (N=61) (p<0.001)^a.