Risk of Lung Cancer in Peripheral Pulmonary Nodules.

Area of Science:

• Pulmonology
• Radiology
• Oncology

Background:

• Accurate classification of small pulmonary nodules is crucial for lung cancer diagnosis.
• Nodules located near or touching the pleura present diagnostic challenges.
• Understanding inter-observer agreement in nodule assessment is vital for clinical practice.

Purpose of the Study:

• To assess the risk of lung cancer misclassification for small pulmonary nodules near the pleura.
• To evaluate inter-observer agreement among radiologists in classifying these nodules.
• To determine if specific nodule characteristics influence diagnostic accuracy.

Main Methods:

• Analysis of 434 pulmonary nodules (45 malignant) from two cohorts: National Lung Screening Trial and healthcare system patients.
• Independent review by two thoracic radiologists assessing nodule morphology and location (pleural-based, septal connection, or neither).
• Measurement of nodule distance to the pleura and classification based on defined criteria.

Main Results:

• Classifying pleural-based nodules with lymph node morphology as benign resulted in 0-7% cancer misclassification and 33% specificity (κ=0.69).
• Subpleural nodules and those with septal connection showed 7-11% cancer misclassification and 40-52% specificity (p<0.0001).
• Nodules with lymph node morphology ≤2 mm from the pleura had 2-7% cancer misclassification and 36-41% specificity (κ=0.78).

Conclusions:

• Classifying nodules with lymph node morphology and septal connection as benign does not significantly increase lung cancer misclassification.
• Classifying nodules within 2 mm of the pleura as benign also avoids significant misclassification of lung cancers.
• These findings support refined criteria for classifying pleural-associated nodules, potentially improving diagnostic accuracy.