Table 1.

Summary of recommendations for the management of patients with indeterminate solitary pulmonary nodules.

Patient with a solid indeterminate solitary pulmonary nodule with a diameter > 0.8 cm

• A functional image, preferably PET, is suggested for nodule characterization, in an individual with low to moderate pre-test probability (5% to 65%). • PET can be indicated with the aim of pre-treatment staging and not for characterizing the nodule in a patient with high pre-test probability (> 65%). • Follow-up with CT (3 to 6 months, 9 to 12 months and 18 to 24 months, using low dose technique without contrast ) is suggested in the following circumstances: – when the clinical probability of malignancy is very low (< 5%); - when the clinical probability is low (< 30% to 40%) and the results of the functional image tests are negative, resulting in a very low post-test probability of malignancy; – when the biopsy is inconclusive and the injury is not hypermetabolic on PET; – when the patient prefers a nonsurgical approach. • Biopsy and/or surgical resection is suggested in individuals with evidence of malignant growth in serial images (unless there are specific contraindications). • Biopsy is suggested in the following circumstances: – when the pre-test clinical probability and imaging findings are discordant; – when the probability of malignancy is low to moderate (10% a 60%); – when there is suspicion of a benign lesion that requires specific medical treatment; – when the patient desires proof of a malignant diagnosis prior to surgery, especially if the risk of surgical complications is high . • Surgery is suggested in the following circumstances: – when the clinical probability of malignancy is high (> 65%); – when the nodule is intensely hypermetabolic on PET or positive on another functional image test; – when the biopsy is suggestive of malignancy; – when the patient prefers to undergo a definitive diagnostic procedure.

Patient with a solid indeterminate solitary pulmonary nodule with a diameter ≤ 0.8 cm and no risk factors for lung cancer

• Nodules ≤ 0.4 cm do not need to be monitored, but the patient must be informed of the potential risks and benefits. • Nodules measuring > 0.4 cm and ≤ 0.6 cm should be reevaluated after 12 months without the need for follow-up if they remain unchanged. • Nodules > 0.6 cm and ≤ 0.8 cm should be reevaluated after 6 to 12 months and again after 18 to 24 months if they remain unchanged.

Patient with a solid indeterminate solitary pulmonary nodule with a diameter ≤ 0.8 cm and one or more risk factors for lung cancer

• Nodules ≤ 0.4 cm should be reevaluated after 12 months, without the need for follow-up if they remain unchanged. • Nodules measuring > 0.4 cm and ≤ 0.6 cm should be reevaluated after 6 to 12 months and again after 18 to 24 months if they remain unchanged. • Nodules > 0.6 cm and ≤ 0.8 cm should be reevaluated after 3 to 6 months, after 9 to 12 months and again after 24 months if they remain unchanged.

Patient with a non-solid (ground-glass) indeterminate pulmonary nodule

• For nodules ≤ 0.5 cm, monitoring is not mandatory. • Nodules > 0.5 cm should be monitored annually for at least three years.

Patient with a part-solid (> 50% ground-glass) indeterminate pulmonary nodule

• For nodules ≤ 0.8 cm, it is suggested that the patient be reevaluated after approximately 3, 12, and 24 months, and that annual CT scans be obtained for an additional 1 to 3 years. • For nodules > 0.8 cm, it is suggested that the chest CT scan be repeated after 3 months, and that that be followed by evaluation by PET, biopsy, or surgical resection for any remaining nodules. • Nodules > 1.5 cm should immediately be submitted to evaluation by PET, biopsy, or surgical resection.

Adapted from American College of Chest Physicians⁽³⁴⁾.