From the Guidelines
No, these small nodules do not require follow-up based on current guidelines. Both the 0.4 cm subpleural nodule in the left lower lobe and the 0.3 cm nodule in the left upper lobe/apex are considered too small to warrant routine surveillance.
Key Points to Consider
- The Fleischner Society guidelines, which are widely accepted in clinical practice, recommend no routine follow-up for solid nodules smaller than 6 mm (0.6 cm) in low-risk individuals 1.
- Even in high-risk patients, such as smokers or those with other risk factors, nodules smaller than 6 mm generally don't require follow-up, as the risk of cancer in these small nodules is less than 1% 1.
- These small nodules are extremely common incidental findings on CT scans and the vast majority represent benign processes such as small areas of scarring, inflammation, or tiny lymph nodes.
- However, if the patient has significant risk factors such as a history of cancer, family history of lung cancer, or occupational exposures, their physician might consider individualized follow-up based on their complete clinical picture.
Clinical Implications
- The decision to follow up on these nodules should be based on the patient's overall clinical risk profile, taking into account factors such as smoking history, family history, and occupational exposures.
- In the absence of significant risk factors, the risk of malignancy in nodules of this size is exceedingly low, and routine follow-up is not recommended 1.
From the Research
Nodule Size and Follow-up
- Non-calcified nodules less than 10mm in size are common on computed tomography (CT) scans, and management algorithms are needed to distinguish between benign and malignant nodules 2.
- For nodules <4mm, a follow-up CT at 12 months is recommended in high-risk persons, whilst for low-risk persons no follow-up is needed 2.
- Solid, smooth or attached indeterminate non-calcified nodules between 5 and 10mm require an annual repeat scan, whilst for purely intra-parenchymal nodules a 3-month repeat scan should be made to assess growth 2.
Specific Nodule Sizes
- A 0.4 cm non-calcified nodule would likely require follow-up, potentially with a 12-month follow-up CT scan, especially if the individual is at high risk for lung cancer 2, 3.
- A 0.3 cm non-calcified nodule would also likely require follow-up, with the same recommendations as the 0.4 cm nodule 2, 3.
Location and Multiplicity of Nodules
- The location of the nodules, such as in the subpleural lateral left lower lobe and ventral margin of the left upper lobe/apex, may be taken into account when assessing the need for follow-up 2.
- The presence of multiple nodules may also be a factor in determining the need for follow-up, as the risk of malignancy increases with the number of nodules 4.
Risk Factors for Malignancy
- Risk factors for malignancy in non-calcified pulmonary nodules include increasing age, size and number of nodules, reduced FEV1 and FVC, and increased pack-years smoking 4.
- The presence of these risk factors may influence the decision to follow up on non-calcified nodules, such as the 0.4 cm and 0.3 cm nodules in question 4, 5.