{
  "abstract": "Objectives Lung cancer screening (LCS) has been shown to reduce lung cancer mortality by around 20%, and several countries recommend it, however, national implementation is not in place anywhere. The overdiagnosis of incidental findings (IFs) of comorbidities play an essential role in the issue of cost-effectiveness which is one of the main factors holding back a nationwide roll-out. Comorbidities are particularly relevant to LCS as most participants qualify for screening due to an extensive smoking history which makes them more at risk of respiratory and cardiovascular comorbidities.The Early Detection of Cancer of the Lung Scotland (ECLS) study showcases a targeted approach to national LCS by implementing the blood-based biomarker EarlyCDT test, reducing the number of patients having to undergo redundant imaging.This study aimed to explore the comorbidities present at baseline, and whether undergoing biomarker screening is associated with an increased incidence of newly discovered comorbidities within the intervention group.Method ECLS was a pragmatic RCT which recruited eligible participants through general practice and community-based recruitment strategies in Scotland. Overall, it included 12 209 participants who, if allocated to the intervention group, underwent an EarlyCDT test. If this resulted in a positive result, the participant underwent a chest-radiograph at baseline and a LDCT scan every six months during a 2-year follow-up period. If participants where part of the control group or obtained a negative EarlyCDT test, they were subject to standard clinical practice by NHS Scotland with no further study involvement. Comorbidity data was obtained from the data repository National Services Scotland (eDRIS prescription as well as ICD10 data). The follow-up analysis had the aim of testing for a relationship between the group allocation and incidence of newly discovered comorbidities during the 5-year follow-up period. Chi-squared testing was used for this univariate analysis to assess the significance of this relationship.Results The baseline exploration showed that 60% of participants had a comorbidity at the start of the study. Older, female and those with a longer smoking history were more at risk. High prevalence conditions were cardiovascular (38.5%), psychiatric/neurological (33.9%), gastrointestinal (29.8%), and respiratory (19.2%). After 5 years of follow-up 20.2% of the total patient cohort had a newly discovered comorbidity. The chi-square analysis showed that there was no significant difference of new incidences when comparing the intervention x and the control y cohort.Conclusions The results of this study indicate that as the addition of a biomarker limits the number of participants undergoing imaging, there is a reduced opportunity for IFs and as a result, less comorbidities might be discovered (such as COPD or calcifications indicating cardiovascular conditions). Here, it must be noted that some studies suggest that IFs can help reduce the all-cause mortality of LCS trials. However, the recent ECLS 5-year follow-up analysis showcased that the hazard ratio for all-cause mortality is 0.610. Thus, when considered alongside the reduction in all-cause mortality, the results of this comorbidity analysis imply that a targeted screening approach may reduce the risk of overdiagnosis and overtreatment resulting from IFs. In comparison to the reported rate of 33.8% significant IFs in the NLST study, our results of 20.2% indicates that approximately 13.6% of overdiagnosis was avoided by the addition of a biomarker prior to LDCT.",
  "authors": [
    {
      "affiliations": [
        "University of St. Andrews, St. Andrews, UK"
      ],
      "name": "Nimue Lilith Romeikat"
    },
    {
      "affiliations": [
        "University of St. Andrews, St. Andrews, UK"
      ],
      "name": "Frank Sullivan"
    },
    {
      "affiliations": [
        "University of St. Andrews, St. Andrews, UK"
      ],
      "name": "Fergus Daly"
    },
    {
      "affiliations": [
        "University of St. Andrews, St. Andrews, UK"
      ],
      "name": "Wenyan Kong"
    }
  ],
  "title": "045 Targeted lung cancer screening is not associated with overdiagnosis of incidental findings",
  "uid": "c4d78999-b54e-5828-ab13-b828c69b63d7"
}