Responsiveness of a Brief Measure of Lung Cancer Screening Knowledge

Our aim was to examine the responsiveness of a lung cancer screening brief knowledge measure (LCS-12). Eligible participants were aged 55-80 years, current smokers or had quit within 15 years, and English speaking. They completed a baseline pretest survey, viewed a lung cancer screening video-based patient decision aid, and then filled out a follow-up posttest survey. We performed a paired samples t-test, calculated effect size, and calculated absolute and relative percent improvement for each item. Participants (n = 30) were primarily White (63%) with less than a college degree (63%), and half were female (50%). Mean age was 61.5 years (standard deviation [SD] = 4.67) and average smoking history was 30.4 pack-years (range = 4.6-90.0). Mean score on the 12-item measure increased from 47.3% correct on the pretest to 80.3% correct on the posttest (mean pretest score = 5.67 vs. mean posttest score = 9.63; mean score difference = 3.97, SD = 2.87, 95% CI = 2.90, 5.04). Total knowledge scores improved significantly and were responsive to the decision aid intervention (paired samples t-test = 7.57, p < .001; Cohen's effect size = 1.59; standard response mean [SRM] = 1.38). All individual items were responsive, yet two items had lower absolute responsiveness than the others (item 8: Without screening, is lung cancer often found at a later stage when cure is less likely? pretest correct = 83.3% vs. posttest = 96.7%, responsiveness = 13.4%; and item 10: Can a CT scan find lung disease that is not cancer? pretest correct = 80.0% vs. posttest = 93.3%, responsiveness = 13.3%). The LCS-12 knowledge measure may be a useful outcome measure of shared decision making for lung cancer screening.