Questions

When following low-risk, small single pulmonary nodules,

1. What is the time sequence for the follow-up CT scans?
2. How long do you re-image them for?

Answers

1. It depends on the size of the nodule and consistency after the initial CT scan.  The current guidelines state:
   1. For solid nodules:
      1. < 6mm recommend no further imaging
      2. > 6mm but < 8mm recommend CT scan at 6-12 months
      3. > 8mm recommend CT scan at 3-6 months, 9-12 months, and 18-24 months
   2. For non-solid (ground glass) nodules:
      1. < 5mm recommend no further imaging
      2. > 5mm recommend annual CT for 3 years
   3. For part-solid (>50% ground glass) nodules:
      1. < 8mm recommend CT scan at 3 months, 12 months, 24 months, and annual for 1-3 years
      2. > 8mm recommend CT scan at 3 months and PET or biopsy
2. Low-risk nodules can be serially scanned for 2 years and if no change, can stop repeat imaging as malignant nodules will show some form of change in 2 years.

References

1. Gould MK, Donington J, Lynch WR. Evaluation of individuals with pulmonary nodules: when is it lung cancer? Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2013; 143(5 Suppl):e93S-e120S. [pubmed]