What is the follow-up protocol for a 6mm pulmonary nodule?

From the Guidelines

For a 6mm lung nodule, I recommend a follow-up CT scan in 6-12 months, with the exact timing depending on your risk factors for lung cancer, as suggested by the Fleischner Society guidelines 1. This approach is based on the guidelines for management of incidental pulmonary nodules detected on CT images, which state that for a single solid nodule of 6-8 mm, a CT scan should be performed at 6-12 months, then consider CT at 18-24 months. The decision on the exact timing of the follow-up should take into account the patient's risk factors for lung cancer, such as smoking history, family history of lung cancer, or previous malignancy. If the patient has risk factors, the follow-up should be closer to 6 months, otherwise, 12 months is appropriate. After the initial follow-up, if the nodule remains stable, additional CT scans should be performed at 18-24 months from the original discovery. It's also important to note that the British Thoracic Society guidelines suggest assessing growth rate using interval CT with capability for automated volumetric analysis for nodules with a chance of malignancy of <10% 1. However, the Fleischner Society guidelines 1 are more recent and provide a clear recommendation for the follow-up of a 6mm lung nodule. The key points to consider are:

• The nodule size and type
• The patient's risk factors for lung cancer
• The timing of the follow-up CT scans
• The need for monitoring and potential further diagnostic investigation if growth is detected. It's essential to discuss these findings with your doctor, who may adjust this plan based on your specific medical history and risk factors.

From the Research

Follow-up for 6mm Lung Nodule

• The probability of malignancy is less than 1% for all nodules smaller than 6 mm and 1% to 2% for nodules 6 mm to 8 mm 2
• Nodules that are 6 mm to 8 mm can be followed with a repeat chest CT in 6 to 12 months, depending on the presence of patient risk factors and imaging characteristics associated with lung malignancy, clinical judgment about the probability of malignancy, and patient preferences 2
• The treatment of an individual with a solid pulmonary nodule 8 mm or larger is based on the estimated probability of malignancy; the presence of patient comorbidities, such as chronic obstructive pulmonary disease and coronary artery disease; and patient preferences 2

Management Options

• Management options include surveillance imaging, defined as monitoring for nodule growth with chest CT imaging, positron emission tomography-CT imaging, nonsurgical biopsy with bronchoscopy or transthoracic needle biopsy, and surgical resection 2
• Part-solid pulmonary nodules are managed according to the size of the solid component, with larger solid components associated with a higher risk of malignancy 2
• Ground-glass pulmonary nodules have a probability of malignancy of 10% to 50% when they persist beyond 3 months and are larger than 10 mm in diameter 2

Diagnostic Evaluation

• Current bronchoscopy and transthoracic needle biopsy methods yield a sensitivity of 70% to 90% for a diagnosis of lung cancer 2
• The use of 18F-FDG PET/CT in staging and response evaluation of lung cancer is critically assessed, with the Tumour Node Metastases (TNM-8) staging systems for NSCLC and MPM presented 3
• The Positron Emission Tomography Response Criteria in Solid Tumours (PERCIST 1.0) is introduced, including its advantages and challenges 3

Surveillance and Follow-up

• For LungRADS-4/PET-negative lesions, the cancer risk remained high despite a lack of activity on PET, and the current surveillance practice of continuing to follow these patients as LungRADS-4 patients is appropriate 4
• The British Thoracic Society guidelines and Fleischner guidelines are referenced for the diagnosis and follow-up of solitary pulmonary nodules, with the use of the Brock (CT-based) and Herder (addition of 18F-FDG PET/CT) models for assessing malignant potential 3