Background Psychosocial impacts of lung cancer screening with low-dose computed tomography (LDCT) are still under evaluation. The questionnaire Consequences Of Screening Lung Cancer (COS-LC) has high content validity in the Danish setting, and is the only condition-specific questionnaire to have been used in published lung cancer screening trials.

Aim To validate an Australian English version of the COS-LC.

Methods Danish versions of the COS-LC questionnaires were translated into Australian English and tested in focus groups for content validity and functionality. Construct validity was assessed with participants of the International Lung Screen Trial (ILST; NCT02871856) Australian cohort. The translated COS-LC was administered before screening and approximately one month after baseline results.

Results COS-LC has four core themes (anxiety, behaviour, dejection, and negative impact on sleep) and twelve lung cancer screening specific themes (focus on symptoms, stigmatisation, introvert, harms of smoking, self-blame, lung cancer, calm, social relations, existential values, impulsivity, empathy, and regretful still smoking). All core themes fit the Rasch model indicating construct validity. Four themes (negative impact on sleep, focus on symptoms, self-blame, and empathy) demonstrated some differential item functioning, which improved with modification of the scales. The remaining themes fit the Rasch model without modification. 

Conclusions The Australian English version of the COS-LC demonstrated high content and construct validity as a condition-specific measure of the psychosocial consequences of lung cancer screening.