What is the recommended management for an elderly female smoker with subcentimeter pulmonary nodules, evidence of air trapping in lungs, and a Lung-RADS (Lung Computed Tomography Screening Reporting and Data System) category 2 classification?

Management of Lung-RADS Category 2 Subcentimeter Nodules in an Elderly Female Smoker

For an elderly female smoker with subcentimeter pulmonary nodules classified as Lung-RADS category 2, no routine follow-up imaging is required—annual screening CT should continue per standard lung cancer screening protocols. 1

Understanding Lung-RADS Category 2 Classification

Lung-RADS category 2 designates nodules as benign or with an extremely low probability of malignancy (less than 1%). 1 This classification applies to:

• Solid nodules measuring ≤5 mm (rounded to nearest millimeter) 1
• Perifissural or subpleural nodules <10 mm with characteristic benign morphology (triangular, lentiform, or oval shape with smooth margins) 1, 2
• Nodules with benign calcification patterns (diffuse, central, laminated, or popcorn) 1

The 2022 Lung-RADS update specifically downgraded many pleural-attached nodules with benign features from category 3 to category 2, eliminating the need for short-interval follow-up. 2

Recommended Management Algorithm

Step 1: Confirm Category 2 Assignment

• Verify nodule size is truly subcentimeter (≤10 mm, with solid nodules ≤5 mm requiring no follow-up) 1
• Assess nodule location and morphology: perifissural/subpleural nodules with smooth, triangular, or lentiform shapes are benign intrapulmonary lymph nodes 1, 3
• Review for benign calcification patterns that definitively exclude malignancy 1

Step 2: No Short-Interval Follow-Up Required

• Do not order 3-month, 6-month, or 12-month surveillance CT scans for category 2 nodules 1, 4
• Avoid unnecessary imaging that increases radiation exposure, healthcare costs, and patient anxiety without clinical benefit 4, 5

Step 3: Continue Annual Lung Cancer Screening

• Return to annual low-dose CT screening as appropriate for this high-risk patient (elderly female smoker) 1, 4, 6
• Ensure patient remains enrolled in structured lung cancer screening program given her smoking history 4, 6

Special Considerations for This Patient

Air Trapping Findings

The presence of air trapping suggests underlying small airways disease or emphysema, which is common in smokers but does not change the management of category 2 nodules. 4 This finding:

• Does not increase the malignancy risk of subcentimeter nodules already classified as category 2 1
• May be a risk factor for future lung cancer development but is already accounted for in the patient's high-risk status as a smoker 1, 6
• Should be documented but does not warrant deviation from standard Lung-RADS category 2 management 1

High-Risk Patient Profile

Despite being an elderly female smoker (high-risk population), the extremely small size and benign features of category 2 nodules override individual risk factors. 1, 4 The Fleischner Society 2017 guidelines explicitly state:

• Solid nodules <6 mm do not require routine follow-up even in high-risk patients 1
• Optional 12-month follow-up may be considered only for nodules with suspicious morphology (spiculation, irregular margins) or upper lobe location, which are not present in typical category 2 nodules 1, 6
• The malignancy probability remains <1% regardless of smoking history when nodules are this small 1, 4

Common Pitfalls to Avoid

Pitfall 1: Over-Surveillance of Benign Nodules

Do not order short-interval follow-up CT scans (3,6, or 12 months) for category 2 nodules, as this represents inappropriate resource utilization and exposes patients to unnecessary radiation. 4, 5, 3 Studies demonstrate that enhanced radiology reports with explicit Lung-RADS recommendations reduce inappropriate follow-up imaging by 40%. 5

Pitfall 2: Misclassifying Perifissural Nodules

Recognize that smooth, triangular, or lentiform nodules adjacent to pleural surfaces are intrapulmonary lymph nodes, not suspicious lesions requiring surveillance. 1, 3, 2 The 2022 Lung-RADS update expanded category 2 criteria to include these nodules in any subpleural location (not just perifissural), improving specificity without sacrificing sensitivity. 3, 2

Pitfall 3: Ignoring Patient Preferences and Comorbidities

While category 2 nodules require no follow-up, ensure the patient understands the rationale and continues annual screening. 1, 6 For elderly patients with significant comorbidities who may not be candidates for curative treatment, even annual screening may not be appropriate. 1, 7

Pitfall 4: Confusing Category 2 with Category 3

Category 2 nodules have <1% malignancy risk and require no short-term follow-up, whereas category 3 nodules (probably benign, 1-2% cancer risk) historically required 6-month follow-up under Lung-RADS v1.1. 1, 8 The distinction is critical for appropriate management.

Evidence Quality and Guideline Consensus

The recommendation for no routine follow-up of category 2 nodules represents strong consensus across multiple high-quality guidelines:

• Fleischner Society 2017 (Grade 1C recommendation): solid nodules <6 mm do not require routine follow-up in low-risk patients, with optional 12-month follow-up in high-risk patients only for suspicious features 1
• British Thoracic Society 2015 (Grade C recommendation): no follow-up for nodules <5 mm or <80 mm³ volume 1
• ACCP 2013 Guidelines: emphasize that management should be guided by estimated malignancy probability, with very low-risk nodules not requiring aggressive surveillance 1, 7

The evidence base is robust, with validation from large screening trials including NELSON and NLST demonstrating that this approach safely identifies clinically significant cancers while minimizing false-positive results. 1, 3