The Importance of Comorbidities at Baseline and 5-Year Follow-Up in a Lung Cancer Biomarker Screening Trial

<b>Background/Objectives</b>: Despite recent lung cancer screening (LCS) studies proving significant mortality reduction, comorbidities are a prominent issue affecting cost effectiveness, which is holding back national implementation. Incidental findings (IFs) of comorbidities make a significant contribution to delayed diagnoses and raise discussions about optimal management plans. This is particularly relevant to national lung cancer screening (NLCS), as the high-risk population qualifying for the screening often have increased likelihood for comorbidities due to their smoking history. <b>Methods</b>: The Early Detection of Cancer of the Lung Scotland (ECLS) (ClinicalTrials.gov identifier NCT01925625) study showcases a targeted approach to NLCS by implementing the blood-based biomarker EarlyCDT-Lung test. Firstly, this paper explored the ECLS dataset for comorbidities present within the screening population at baseline A chi-square analysis was then undertaken to investigate the relationship of cohort allocation and incidence of new comorbidities over the five-year follow-up period. <b>Results</b>: High prevalence conditions were cardiovascular (38.5%), neurological/psychiatric (33.9%), gastrointestinal (29.8%), and respiratory (19.2%). While 20.3% of the total patient cohort showed a newly discovered comorbidity, there was no significant variation in new incidences between the intervention and control cohort. <b>Conclusions</b>: When considering these results alongside the all-cause mortality reduction shown in previous analyses, they indicate that this targeted approach to LCS might help improve the benefit-harm ratio through the introduction of biomarkers. Further refining selection criteria for low-dose CT screening might contribute to minimising the risk of overdiagnosis and overtreatment.