Risk of Malignancy in Cystic Lung Lesions in a Lung Cancer CT Screening Program

Area of Science:

• Radiology
• Oncology
• Pulmonology

Background:

• Lack of consensus on malignancy risk and natural history of cystic lung lesions.
• Need for imaging characteristics to assess malignancy risk in lung cancer screening programs.

Purpose of the Study:

• Evaluate imaging features associated with malignancy risk in cystic lung lesions.
• Analyze the natural history of these lesions within a lung cancer screening context.

Main Methods:

• Retrospective analysis of CT lung cancer screening exams (January 2015 - July 2023).
• Review of radiology reports for cystic lesions and analysis of baseline CT images for morphology and size.
• Evaluation of follow-up CT scans for lesion changes and analysis of cancer risk using Kaplan-Meier curves.

Main Results:

• Among 235 cystic lung lesions identified in 15,762 patients, 33 (14%) were associated with lung cancer.
• Nodular wall thickening (OR, 11) and solid nodules (OR, 5.3), especially with a ground-glass component (OR, 24), increased cancer risk.
• Unilocular lesions without wall thickening (n=46) showed no malignancy. Lesion growth/complexity over time correlated with malignancy risk (P < .001).

Conclusions:

• Cystic lung lesions with nodular wall thickening carry an increased malignancy risk.
• Unilocular cystic lesions without wall thickening have minimal malignancy risk.
• Malignant cystic lesions typically display slow growth and are diagnosed at early stages (0 or I).