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. 2021 Jul 9;11(7):e045160. doi: 10.1136/bmjopen-2020-045160

Table 3.

Changes in lung cancer screening knowledge before and after viewing the decision aid (n=219)

Question Pre, correct answer
n (%)
Post, correct answer
n (%)
Difference n (%) P value
Who do you think is more likely to be diagnosed with lung cancer in their lifetime?
People who get screened*/People are equally likely to be diagnosed/People who do NOT get screened
39 (17.8) 79 (36.1) 40 (+18.3) <0.001
All lung cancers will eventually cause illness and death if they are not found and treated.
True/False*/Don’t know
35 (16.0) 120 (54.8) 115 (+38.8) <0.001
When screening finds cancer, doctors can tell whether it will ever cause harm.
True/False*/Don’t know
44 (20.1) 142 (64.8) 98 (+44.7) <0.001
Even lung cancers that may not cause any health problems are likely to be treated.
True*/False/Don’t know
161 (73.5) 171 (78.1) 10 (+4.6) 0.21
Screening leads some people with a harmless cancer to get treatment they do not need.
True*/False/Don’t know
48 (21.9) 155 (70.8) 107 (+48.9) <0.001
Screening tests find harmless lung cancers about as often as they prevent death from lung cancer.
True*/False/Don’t know
69 (31.5) 125 (57.1) 56 (+25.6) <0.001
Which of these two statements best describes over-detection from screening?
Screening finds an abnormality but extra tests show it is not cancer/ Screening finds a cancer that would never have caused trouble*
38 (17.4) 66 (30.1) 28 (+12.7) <0.01
Out of 1000 people like you who get a low dose CT scan yearly for 3 years, about how many will be diagnosed with lung cancer?
None/Very few (1–10)/Few (11–30)*/Some (31–200)*/Many (201–500)/Most (501–1000)/Don’t know
85 (38.8) 125 (57.1) 40 (+18.3) <0.001
Out of 1000 people like you who get a low dose CT scan yearly for 3 years, about how many will have their lives prolonged from lung cancer screening?
None/Very few (1–10)*/Few (11–30)*/Some (31–200)/Many (201–500)/Most (501–1000)/Don’t know
36 (16.4) 84 (38.4) 48 (+22.0) <0.001
Out of 1000 people like you who get a low dose CT scan yearly for 3 years, about how many will be diagnosed with cancer that would not have needed treatment?
None/Very few (1–10)*/Few (11–30)* /Some (31–200)/Many (201–500)/Most (501–1000)/Don’t know
54 (24.7) 101 (46.1) 47 (+21.4) <0.001

*Correct answer(s).