Psychosocial consequences of false positives in the Danish Lung Cancer CT Screening Trial: a nested matched cohort study

Abstract

Objectives: Lung cancer CT screening can reduce lung cancer mortality, but high false-positive rates may cause adverse psychosocial consequences. The aim was to analyse the psychosocial consequences of false-positive lung cancer CT screening using the lung cancer screening-specific questionnaire, Consequences of Screening in Lung Cancer (COS-LC).

Design and setting: This study was a matched cohort study, nested in the randomised Danish Lung Cancer Screening Trial (DLCST).

Participants: Our study included all 130 participants in the DLCST with positive CT results in screening rounds 2-5, who had completed the COS-LC questionnaire. Participants were split into a true-positive and a false-positive group and were then matched 1:2 with a control group (n=248) on sex, age (±3 years) and the time of screening for the positive CT groups or clinic visit for the control group. The true positives and false positives were also matched 1:2 with participants with negative CT screening results (n=252).

Primary outcomes: Primary outcomes were psychosocial consequences measured at five time points.

Results: False positives experienced significantly more negative psychosocial consequences in seven outcomes at 1 week and in three outcomes at 1 month compared with the control group and the true-negative group (mean ∆ score >0 and p<0.001). True positives experienced significantly more negative psychosocial consequences in one outcome at 1 week (mean ∆ score 2.86 (95% CI 1.01 to 4.70), p=0.0024) and in five outcomes at 1 month (mean ∆ score >0 and p<0.004) compared with the true-negative group and the control group. No long-term psychosocial consequences were identified either in false positives or true positives.

Conclusions: Receiving a false-positive result in lung cancer screening was associated with negative short-term psychosocial consequences. These findings contribute to the evidence on harms of screening and should be taken into account when considering implementation of lung cancer screening programmes.

Trial registration number: NCT00496977.

Keywords: computed tomography; preventive medicine; public health; thoracic medicine.

Conflict of interest statement

Competing interests: None declared.

© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Distribution of screening results and final diagnoses in the DLCST, and response rates of the matched groups at five time points: baseline, 1 week, 1, 6 and 18 months. COS-LC, Consequences of Screening in Lung Cancer; DLCST, Danish Lung Cancer Screening Trial.

Figure 2

The mean score of the nine psychosocial outcomes of Consequences of Screening in Lung Cancer (COS-LC) part I for the diagnostic groups and the control group in the Danish Lung Cancer Screening Trial at five time points: baseline, 1 week, 1, 6 and 18 months. The means of COS-LC part I scales are compared between all groups at each time point and significant differences between the groups are described below each scale (see online supplementary appendix 1 for details of the adjusted analyses). After adjustment for multiple testing by the method of Benjamini-Hochberg, the level of statistical significance was assessed at 0.0043; 0=baseline; 1 w=1 week after screening; 1 m, 6 ms and 18 ms=1, 6 and 18 months after final diagnostic result; the higher the score the more negative psychosocial reaction.

Figure 3

The mean score of the six psychosocial outcomes of Consequences of Screening in Lung Cancer (COS-LC) part II for the diagnostic groups in the Danish Lung Cancer Screening Trial at three time points: 1, 6 and 18 months. The means of COS-LS Part II scales are compared between the three screened groups at each time point after the final diagnostic result and significant differences between the groups are described below each scale (see online supplementary appendix 1 for details of the adjusted analyses). After adjustment for multiple testing by the method of Benjamini-Hochberg, the level of statistical significance was assessed at 0.0043; 0=baseline; 1 w=1 week after screening; 1 m, 6 ms and 18 ms=1, 6 and 18 months after final diagnostic result; the higher the score the more psychosocial reaction.