In a 72‑year‑old smoker undergoing low‑dose computed tomography (LDCT) screening who now has a new 6 × 9 mm right upper‑lobe nodule minimally avid on positron emission tomography (PET) and a new 3 mm left upper‑lobe nodule, with other stable nodules, should these nodules be followed with yearly imaging or a more frequent surveillance protocol?

Management of New Pulmonary Nodules in a High-Risk Smoker

These nodules require more frequent surveillance than yearly imaging—specifically, the 6-9 mm nodule warrants CT follow-up at 6-12 months, then again at 18-24 months, while the 3 mm nodule requires no routine follow-up. 1

Risk Stratification

This 72-year-old smoker represents a high-risk patient given:

• Active smoking history
• Age ≥65 years
• Upper lobe location of the dominant nodule
• New nodule development (interval change is inherently suspicious) 1

Management Algorithm by Nodule Size

The 6-9 mm Right Upper Lobe Nodule

This nodule falls into the 6-8 mm category and requires active surveillance, not yearly monitoring. 1

According to Fleischner Society 2017 guidelines for high-risk patients with solid nodules 6-8 mm:

• Initial follow-up CT at 6-12 months
• Subsequent CT at 18-24 months 1

The upper lobe location and smoking history further elevate concern, as these features are associated with higher malignancy risk even in this size range. 1

Role of PET Imaging

While the report mentions the nodule is "near the resolution of PET," **PET/CT has limited sensitivity for nodules <10 mm**, with sensitivity dropping to approximately 88% overall and even lower for smaller lesions. 2 For solid nodules 6-8 mm, **CT surveillance is the appropriate initial strategy rather than PET/CT**, which is typically reserved for nodules >8 mm or those demonstrating growth. 1, 2

The 3 mm Left Upper Lobe Nodule

No routine follow-up is required for this nodule. 1

Nodules <6 mm have an estimated cancer risk <1% and do not meet the threshold for routine surveillance, even in high-risk patients. 1 However, this nodule will be reassessed on the follow-up scans obtained for the larger 6-9 mm nodule.

The Stable Nodules

Stable nodules on serial imaging are reassuring and suggest benign etiology, but they should continue to be documented on subsequent scans performed for the new nodules. 1 True stability over ≥2 years generally indicates benign disease.

Critical Pitfalls to Avoid

Do not assume these nodules are benign simply because they are small. The combination of:

• New appearance (not present on prior imaging)
• High-risk patient profile (age, smoking)
• Upper lobe location
• Size in the 6-8 mm range

...creates a cumulative cancer risk well above 1%, mandating structured surveillance. 1

Do not extend surveillance intervals to yearly for the 6-9 mm nodule. This represents a common error that can delay diagnosis of early-stage lung cancer. The Fleischner guidelines specifically recommend shorter intervals (6-12 months, then 18-24 months) for this exact clinical scenario. 1

Do not rush to PET/CT or biopsy at this stage. For nodules 6-8 mm, initial CT surveillance is the appropriate strategy, with PET/CT or tissue sampling reserved for nodules >8 mm or those demonstrating growth on follow-up imaging. 1, 2

Surveillance Protocol Summary

Recommended timeline:

1. First follow-up CT: 6-12 months from baseline scan 1
2. Second follow-up CT: 18-24 months from baseline (if stable at first follow-up) 1
3. If growth is detected at any point: Consider 3-month CT, PET/CT, or tissue sampling depending on degree of growth and clinical context 1

This protocol balances the need to detect early-stage lung cancer (which has significantly better outcomes with 5-year survival rates >70% for stage I disease) against the harms of overinvestigation, false positives, and unnecessary procedures. 3