In Lung Cancer Screening By CT Incidental Findings Are Frequent And Often Of Clinical Importance

Introduction: Incidental findings during CT screening of a large population may cause a substantial burden of additional diagnostic workup and the patients may undergo unnecessary and potentially harmful procedures. Aim: We investigated the extent of significant incidental findings during five years of CT screening for lung cancer in the Danish Lung Cancer Screening Trial (DLCST). Material and methods: DLCST recruited 4,104 healthy current and former smokers (age: 50-70), who were randomised to either five annual chest CT or no intervention. CT Scans were performed supine after full inspiration with caudocranial scan direction including the entire ribcage and upper abdomen with a low dose technique. Two experienced chest radiologists read all CT scans and registered lung nodules as well as incidental findings. Findings were discussed at weekly consultations, and clinical significant findings were defined as referral to relevant departments for futher workup, where we followed participants closely by their medical records. Results: 140 participants (7%) had 148 clinical significant incidental findings localised in larynx (1), thyreoid (3) gastro-esophageal (9), breast (16), cardiac (5), mediastinum (12), aorta (28), liver-and-gall-bladder (18), pancreas (6), spleen (1), intestines (2), kidneys (40), skin (2), chest-wall (3) and vertebral column (2). 22 (16%) underwent invasive procedures that lead to a cancer diagnosis in 10 participants. 118 had one or more non-invasive clinical check-ups. Conclusion: The extent of incidental findings during CT screening of lung cancer is considerable and may lead to diagnosis of clinical significant diseases.