What is the recommended follow-up for a 6mm right lower lobe lateral basal segment pleural-based nodule?

From the Guidelines

For a 6mm right lower lobe lateral basal segment pleural-based nodule, the recommended follow-up is a repeat chest CT scan in 6-12 months to monitor for any changes in size or characteristics. This recommendation is based on the guidelines from the Fleischner Society 2017 1, which suggest that for solid nodules ≥6 mm, a CT scan should be performed at 6–12 months to confirm persistence, then CT every 2 years until 5 years. The pleural-based location of the nodule does not significantly alter the management approach for a nodule of this size.

Key Considerations

• The nodule size of 6mm represents a low but not negligible risk for malignancy, hence the need for follow-up.
• The follow-up interval of 6-12 months allows for the detection of any changes in the nodule's size or characteristics without subjecting the patient to unnecessary radiation exposure.
• If the nodule remains stable after the initial follow-up scan, additional imaging would typically be recommended at 18-24 months from the original detection to establish long-term stability.
• Any growth or concerning changes observed during follow-up, such as development of irregular margins, increasing density, or growth rate exceeding 2mm in diameter, should prompt more aggressive evaluation, including possible biopsy or resection.

Patient Advice

Patients should be advised to report any new symptoms such as persistent cough, chest pain, or hemoptysis during the monitoring period. This surveillance approach balances the need to detect potentially malignant lesions early while avoiding unnecessary invasive procedures for what are often benign findings. The guidelines from the American College of Chest Physicians 1 also support the use of CT surveillance for solid nodules, but the Fleischner Society guidelines 1 provide more specific recommendations for the follow-up of nodules based on their size.

From the Research

Follow-up for a 6mm Right Lower Lobe Lateral Basal Segment Pleural-Based Nodule

• The recommended follow-up for a 6mm right lower lobe lateral basal segment pleural-based nodule is based on the Lung CT Screening Reporting and Data System (Lung-RADS) version 2022, which recommends annual follow-up rather than short-term follow-up for pleural-attached nodules with smooth margins and triangular, lentiform, oval, or semicircular shapes 2.
• According to Lung-RADS version 2022, pleural-attached solid nodules less than 10 mm in average diameter with smooth margins and specific shapes have a high likelihood of benignity and are assigned to category 2 (benign), which limits additional workup 2.
• A study published in the AJR. American journal of roentgenology found that malignant nodules manifest growth slowly on follow-up CT, and 3-month follow-up CT has very low yield, suggesting that stability at 3-month follow-up should not instill high confidence in benignancy 3.
• The probability of malignancy for nodules smaller than 6 mm is less than 1%, and for nodules 6 mm to 8 mm, it is 1% to 2%, according to a review published in JAMA 4.
• For nodules 6 mm to 8 mm, follow-up with a repeat chest CT in 6 to 12 months is recommended, depending on patient risk factors, imaging characteristics, and clinical judgment 4.
• Another study published in the Lancet found that lesions up to 5 mm can be checked again at 12 months without major risks of progression, supporting the idea of annual follow-up for small nodules 5.
• It is essential to consider patient risk factors, imaging characteristics, and clinical judgment when determining the follow-up strategy for a 6mm right lower lobe lateral basal segment pleural-based nodule 6, 4.