Background
Study objectives and hypotheses
Methods
Study design
Decision aid
Gist information
Extended information
Recruitment
Participants
Study duration
Randomisation
Sample size and assumptions
Ethics
Measures
Demographic and personal information
Knowledge
Attitudes (values) towards taking part in PROMISE
Intention to participate in the PROMISE study
Decisional conflict and anticipated decisional regret
Website usage
Construct | Time of assessment | |
---|---|---|
Before exposure to decision aid | After exposure to decision aid | |
Demographic and personal information | ✓ | ✗ |
Worry about breast and ovarian cancer | ✓ | ✗ |
Genetic literacy | ✓ | ✗ |
Health literacy | ✓ | ✗ |
Perceived risk of ovarian cancer | ✓ | ✓ |
Knowledge about ovarian cancer | ✓ | ✓ |
Knowledge about PROMISE | ✗ | ✓ |
Attitudes towards taking part in PROMISE | ✗ | ✓ |
Intention to take part in PROMISE | ✗ | ✓ |
Decisional conflict | ✗ | ✓ |
Anticipated decisional regret | ✗ | ✓ |
Website usage | ✗ | ✓ |
Statistical analyses
Results
Sample characteristics
Total (n = 1031) | Gist group (n = 512) | Extended group (n = 519) | |
---|---|---|---|
N (%) |
N (%) |
N (%) | |
Age | |||
18–29 | 199 (19.3) | 109 (21.3) | 90 (17.3) |
30–39 | 222 (21.5) | 104 (20.3) | 118 (22.7) |
40–49 | 228 (22.1) | 115 (22.5) | 113 (21.8) |
50–59 | 210 (20.4) | 99 (19.3) | 111 (21.4) |
60+ | 172 (16.7) | 85 (16.6) | 87 (16.8) |
Ethnicity | |||
White | 821 (79.6) | 402 (78.5) | 419 (80.7) |
Asian | 95 (9.2) | 52 (10.1) | 43 (8.3) |
Black | 68 (6.6) | 31 (6.0) | 37 (7.1) |
Mixed | 34 (3.3) | 20 (4.0) | 14 (2.7) |
Other | 8 (0.8) | 6 (1.2) | 2 (0.4) |
First language | |||
English | 937 (90.9) | 460 (89.8) | 477 (91.9) |
Other | 93 (9.0) | 52 (10.2) | 41 (7.9) |
Education | |||
Degree or equivalent | 268 (26.0) | 130 (25.4) | 138 (26.6) |
Higher education | 112 (10.9) | 55 (10.7) | 57 (11.0) |
A Level or equivalent | 235 (22.8) | 112 (21.9) | 123 (23.7) |
GCSEs grades A*-C or equivalent | 256 (24.8) | 140 (27.3) | 116 (22.4) |
Other qualifications | 83 (8.1) | 42 (8.2) | 41 (7.9) |
No formal qualifications | 73 (7.1) | 32 (6.3) | 41 (7.9) |
Family history of breast cancer (yes) | 258 (25.0) | 125 (24.4) | 133 (25.6) |
Family history of ovarian cancer (yes) | 84 (8.1) | 47 (9.2) | 37 (7.1) |
Comparative risk of ovarian cancer | |||
Much lower than others | 79 (7.7) | 37 (7.2) | 42 (8.1) |
Lower than others | 147 (14.3) | 81 (15.8) | 66 (12.7) |
Same as others | 709 (68.8) | 350 (68.4) | 359 (69.2) |
Higher than others | 85 (8.2) | 39 (7.6) | 46 (8.9) |
Much higher than others | 11 (1.1) | 5 (1.0) | 6 (1.2) |
Worry about breast cancer | |||
Never | 102 (9.9) | 43 (8.4) | 59 (11.4) |
Rarely | 270 (26.2) | 139 (27.1) | 131 (25.2) |
Sometimes | 457 (44.3) | 235 (45.9) | 222 (42.8) |
Often | 152 (14.7) | 70 (13.7) | 82 (15.8) |
Always | 50 (4.8) | 25 (4.9) | 25 (4.8) |
Worry about ovarian cancer | |||
Never | 256 (24.8) | 115 (22.5) | 141 (27.2) |
Rarely | 354 (34.3) | 184 (35.9) | 170 (32.8) |
Sometimes | 348 (33.8) | 177 (34.6) | 171 (32.9) |
Often | 53 (5.1) | 22 (4.3) | 31 (6.0) |
Always | 20 (1.9) | 14 (2.7) | 6 (1.2) |
Previous participation in cancer screening tests | |||
Cervical | 774 (75.1) | 377 (73.6) | 397 (76.5) |
Breast | 400 (38.8) | 193 (37.7) | 207 (39.9) |
Colorectal | 162 (15.7) | 79 (15.4) | 83 (16.0) |
None of above | 214 (20.8) | 114 (22.3) | 100 (19.3) |
Knowledge
Pre decision-aid | Post decision-aid | P-value for difference between groups | ||||
---|---|---|---|---|---|---|
Response options | Gist group (n = 512) N (%) | Extended group (n = 519) N (%) | Gist group (n = 512) N (%) | Extended group (n = 519) N (%) | ||
Knowledge | ||||||
Summary scores | ||||||
Knowledge about ovarian cancer (range = 0–10), mean (SD) | 5.75 (1.63) | 5.66 (1.48) | 6.79 (1.84) | 6.76 (1.81) |
t(1029) = 0.30, p = 0.766 | |
Knowledge about PROMISE (range = 0–6), mean (SD) | n/a | n/a | 4.02 (1.73) | 3.92 (1.70) |
t(1029) = 0.87, p = 0.386 | |
Individual item scores | ||||||
Knowledge about ovarian cancer:
| ||||||
The average risk of a woman developing ovarian cancer in her lifetime is (1 in 50) | 1) 1 in 8
2) 1 in 50
3) 1 in 1000 | 141 (27.5)
280 (54.7)
91 (17.8) | 144 (27.7)
256 (49.3)
119 (22.9) | 117 (22.9)
347 (67.8)
48 (9.4) | 105 (20.2)
346 (66.7)
68 (13.1) | |
Ovarian cancer mostly affects older women (True) |
True
Not true Not sure |
106 (20.7)
320 (62.5) 86 (16.8) |
85 (16.4)
330 (63.6) 104 (20.0) |
246 (48.0)
203 (39.6) 63 (12.3) |
211 (40.7)
238 (45.9) 70 (13.5) | |
Ovarian cancer can easily be found early with an ultrasound scan (Not true) | True
Not true
Not sure | 238 (46.5)
89 (17.4)
185 (36.1) | 233 (44.9)
85 (16.4)
201 (38.7) | 211 (41.2)
124 (24.2)
177 (34.6) | 210 (40.5)
147 (28.3)
162 (31.2) | |
There are some factors which increase the risk of ovarian cancer. Please tick all that you think apply: | ||||||
Being over 50 years old (Yes) |
Yes
No |
222 (43.4)
290 (56.6) |
213 (41.0)
306 (59.0) |
340 (66.4)
172 (33.6) |
322 (62.0)
197 (38.0) | |
Being overweight (Yes) |
Yes
No |
270 (52.7)
242 (47.3) |
285 (54.9)
234 (45.1) |
342 (66.8)
170 (33.2) |
356 (68.6)
163 (31.4) | |
Smoking (Yes) |
Yes
No |
293 (57.2)
219 (42.8) |
294 (56.6)
225 (43.4) |
344 (67.2)
168 (32.8) |
351 (67.6)
168 (32.4) | |
Family history (Yes) |
Yes
No |
420 (82.0)
92 (18.0) |
436 (84.0)
83 (16.0) |
413 (80.7)
99 (19.3) |
445 (85.7)
74 (14.3) | |
Taking the pill (No) | Yes
No
| 197 (38.5)
315 (61.5)
| 197 (38.0)
322 (62.0)
| 150 (29.3)
362 (70.7)
| 162 (31.2)
357 (68.8)
| |
Having children (No) | Yes
No
| 67 (13.1)
445 (86.9)
| 58 (11.2)
461 (88.8)
| 53 (10.4)
459 (89.6)
| 50 (9.6)
469 (90.4)
| |
Breastfeeding (No) | Yes
No
| 9 (1.8)
503 (98.2)
| 16 (3.1)
503 (96.9)
| 12 (2.3)
500 (97.7)
| 16 (3.1)
503 (96.9)
| |
Knowledge about PROMISE:
| ||||||
Genetic testing for ovarian cancer involves giving a blood sample (True) |
True
Not true Not sure | n/a | n/a |
279 (54.5)
67 (13.1) 166 (32.4) |
282 (54.3)
69 (13.3) 168 (32.4) | |
PROMISE uses genetic information to estimate the risk of developing ovarian cancer (True) |
True
Not true Not sure | n/a | n/a |
360 (70.3)
29 (5.7) 123 (24.0) |
357 (68.8)
21 (4.0) 141 (27.2) | |
Learning about personal risk of ovarian cancer may affect other family members (True) |
True
Not true Not sure | n/a | n/a |
383 (74.8)
43 (8.4) 86 (16.8) |
392 (75.5)
56 (10.8) 71 (13.7) | |
Most women who take part in PROMISE will learn that they are at high risk of ovarian cancer (Not true) | True
Not true
Not sure | n/a | n/a | 61 (11.9)
336 (65.6)
115 (22.5) | 83 (16.0)
320 (61.7)
116 (22.4) | |
There is nothing that women who are at high risk of ovarian cancer can do to reduce their risk of ovarian cancer (Not true) | True
Not true
Not sure | n/a | n/a | 53 (10.4)
337 (65.8)
122 (23.8) | 56 (10.8)
313 (60.3)
150 (28.9) | |
Women who take part in PROMISE will get some information about their risk of breast cancer (True) |
True
Not true Not sure | n/a | n/a |
361 (70.5)
15 (2.9) 136 (26.6) |
372 (71.7)
27 (5.2) 120 (23.1) | |
Attitudes towards taking part in PROMISE | ||||||
For me, taking part in PROMISE would be: | ||||||
A bad thing (1) not a bad thing (5) | n/a | n/a | 3.93 (0.91) | 3.89 (0.86) | ||
Not beneficial (1) beneficial (5) | n/a | n/a | 3.89 (0.94) | 3.84 (0.90) | ||
Not a good thing (1) a good thing (5) | n/a | n/a | 3.93 (0.91) | 3.89 (0.88) | ||
Not worthwhile (1) worthwhile (5) | n/a | n/a | 3.91 (0.95) | 3.88 (0.93) | ||
Not important (1) important (5) | n/a | n/a | 3.82 (1.0) | 3.82 (0.94) | ||
Harmful (1) not harmful (5) | n/a | n/a | 4.04 (0.88) | 4.03 (0.86) | ||
Total mean (range = 1–5) (SD) | n/a | n/a | 3.92 (0.83) | 3.89 (0.79) | t(1029) = 0.60, p = 0.550 | |
Intention to participate in PROMISE | ||||||
Definitely not | n/a | n/a | 18 (3.5%) | 20 (3.9%) | ||
Probably not | n/a | n/a | 114 (22.3%) | 114 (22.0%) | ||
Yes probably | n/a | n/a | 255 (49.8%) | 267 (51.4%) | ||
Yes definitely | n/a | n/a | 125 (24.4%) | 118 (22.7%) | ||
Mean score (range = 1–4) (SD) | n/a | n/a | 2.95 (0.78%) | 2.93 (0.77%) | t(1029) = 0.43, p = 0.671 |
Attitudes (values) towards participating in PROMISE
Intention to participate in the PROMISE study
Decisional conflict and anticipated decision regret
Item (1 = strongly disagree, 4 = strongly agree) | Overall (n = 1031) | Gist group (n = 512) | Extended group (n = 519) |
---|---|---|---|
Decisional conflict | Mean (SD) % Agree/Strongly agree | ||
I would be satisfied with my decision of whether or not to take part in PROMISE | 1.91 (.51) 92.6 | 1.91 (.52) 91.6 | 1.90 (.49) 93.6 |
I feel I would make an informed choice about taking part in PROMISE | 1.84 (.52) 94.4 | 1.83 (.52) 94.5 | 1.85 (.51) 94.2 |
I know the risks of taking part in PROMISE | 2.10 (.67) 76.9 | 2.09 (.67) 77.3 | 2.11 (.67) 76.5 |
I feel unsure of what I would choose - taking part in PROMISE or not taking part | 2.53 (.76) 53.6 | 2.57 (.78) 52.0 | 2.48 (.74) 55.3 |
The decision about whether or not to take part in PROMISE would be easy for me | 2.22 (.70) 67.4 | 2.18 (.71) 69.5 | 2.25 (.70) 65.3 |
I would expect to stick with my decision of whether or not to take part in PROMISE | 1.93 (.54) 90.5 | 1.94 (.56) 89.5 | 1.91 (.52) 91.5 |
Mean subscale score (range = 1–4) (SD) | 2.09 (0.32) | 2.09 (0.32) | 2.08 (0.32)a
|
Anticipated decisional regret | |||
If I did not take part in PROMISE, I would feel regret | 2.52 (.72) 49.3 | 2.50 (.71) 48.6 | 2.54 (.72) 49.9 |
If I did not take part in PROMISE, I would later wish I had | 2.60 (.72) 54.8 | 2.62 (.71) 56.7 | 2.57 (.73) 52.9 |
Mean subscale score (range = 1–4) (SD) | 2.56 (0.66) | 2.56 (0.66) | 2.56 (0.67)b
|
Website usage
Item | Response options | Total sample (n = 1031)
N (%) | Gist group (n = 512)
N (%) | Extended group (n = 519)
N (%) |
---|---|---|---|---|
I read all the information on the website | Very thoroughly Quite thoroughly Briefly Just the relevant parts | 216 (21.0) 446 (43.3) 268 (26.0) 101 (9.8) | 100 (19.5) 233 (45.5) 134 (26.2) 45 (8.8) | 116 (22.4) 213 (41.0) 134 (25.8) 56 (10.8) |
Mean (range = 1–4) (SD) | 2.25 (0.90) | 2.24 (0.87) | 2.25 (0.92)a
| |
Imagine you were invited to take part in the study described on the website when you answer the following questions. There was enough information on the website to make a decision whether or not to take part in the study. | Strongly agree Agree Disagree Strongly disagree | 281 (27.3) 679 (65.9) 64 (6.2) 7 (0.7) | 141 (27.5) 345 (67.4) 24 (4.7) 2 (0.4) | 140 (27.0) 334 (64.4) 40 (7.7) 5 (1.0) |
Mean (range = 1–4) (SD) | 1.80 (0.57) | 1.78 (0.54) | 1.83 (0.60)b
|