Evaluation of solitary pulmonary nodule

A solitary pulmonary nodule is defined as a relatively round lesion that is <3 cm in diameter and completely surrounded by lung parenchyma. It is distinct from a lung lesion >3 cm in diameter, which is considered a lung mass and is usually presumed to be malignant until proved otherwise.[1]Ost D, Fein A. Evaluation and management of the solitary pulmonary nodule. Am J Respir Crit Care Med. 2000 Sep;162(3 Pt 1):782-7. http://www.atsjournals.org/doi/full/10.1164/ajrccm.162.3.9812152 [2]Ost DE, Gould MK. Decision making in patients with pulmonary nodules. Am J Respir Crit Care Med. 2012 Feb 15;185(4):363-72. https://www.atsjournals.org/doi/10.1164/rccm.201104-0679CI http://www.ncbi.nlm.nih.gov/pubmed/21980032?tool=bestpractice.com ​

A solitary pulmonary nodule may be detected incidentally following computed tomography (CT) imaging/chest X-ray (CXR), or may be identified via lung cancer surveillance programs which utilize low-dose CT (LDCT). Pulmonary nodules are identified in approximately 1.6 million people annually in the US.[3]Mazzone PJ, Lam L. Evaluating the patient with a pulmonary nodule: A Review. JAMA. 2022 Jan 18;327(3):264-73. http://www.ncbi.nlm.nih.gov/pubmed/35040882?tool=bestpractice.com

All pulmonary nodules - including solid nodules, sub-solid nodules (also known as semi-solid nodules, which have both solid and ground-glass components), and nodules with a pure ground glass appearance - require assessment for risk of malignancy, with further action to be taken as appropriate.[4]Callister ME, Baldwin DR, Akram AR, et al. British Thoracic Society guidelines for the investigation and management of pulmonary nodules. Thorax. 2015 Aug;70 Suppl 2:ii1-54. https://thorax.bmj.com/content/70/Suppl_2/ii1.long [5]American College of Radiology. Lung-RADS®. Nov 2022 [internet publication]. https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Reporting-and-Data-Systems/Lung-RADS

Most national guidelines make separate recommendations regarding the evaluation and management of solid pulmonary nodules, pure ground-glass nodules, and sub-solid nodules.

Management goals

Following identification of a solitary pulmonary nodule, careful diagnostic evaluation and management is required to distinguish the benign nodule from the malignant nodule and, when malignancy is either confirmed or strongly suspected, to expedite treatment.

For solitary pulmonary nodules, established clinical features (e.g., patient age, smoking status) and radiographic findings (e.g., calcification, growth rate, size) help determine a probability of malignancy. These factors can be used to inform risk calculations based on models derived from large screening studies.[6]González Maldonado S, Delorme S, Hüsing A, et al. Evaluation of prediction models for identifying malignancy in pulmonary nodules detected via low-dose computed tomography. JAMA Netw Open. 2020 Feb 5;3(2):e1921221. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2760895 http://www.ncbi.nlm.nih.gov/pubmed/32058555?tool=bestpractice.com [7]McWilliams A, Tammemagi MC, Mayo JR, et al. Probability of cancer in pulmonary nodules detected on first screening CT. N Engl J Med. 2013 Sep 5;369(10):910-9. https://www.nejm.org/doi/10.1056/NEJMoa1214726?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200www.ncbi.nlm.nih.gov http://www.ncbi.nlm.nih.gov/pubmed/24004118?tool=bestpractice.com ​​​ If risk is deemed to be sufficiently high, noninvasive and/or invasive testing is used to more accurately determine the probability of malignancy to a level that enables a decision to be made regarding observation or resection. Therefore, the proper use of these tests mandates knowledge about their performance characteristics.