The Thoracic Society of Australia and New Zealand

The Thoracic Society of Australia and New Zealand (TSANZ) is the only health peak body representing a range of professions (medical specialists, scientists, researchers, academics, nurses, physiotherapists, students and others) across various disciplines within the respiratory/sleep medicine field in Australia and New Zealand. The TSANZ is a Health Promotion Charity. TSANZ is committed to serving the professional needs of its members by improving knowledge and understanding of lung disease, with the ultimate goals being to prevent respiratory illness through research and health promotion and to improve health care for people with respiratory illness.

Do not routinely follow-up solid pulmonary nodules smaller than 6 mm detected in low- risk patients

Date reviewed: 1 June 2021

There is a lack of direct evidence related to cancer probability in small nodules in low-risk patients. The National Lung Screening Trial, the largest randomised study of lung cancer screening in a high-risk population to date, showed that that CT lung screening reduces lung cancer mortality in high-risk patients when the minimum size of a positive pulmonary nodule is set at 4 mm. As more than half of baseline examinations in the study were positive for nodules 4 to 6 mm in size, raising the threshold for a positive result to 6 mm would decrease the baseline positive rate from 27.3% to around 13.4%.

Since the positive predictive value (PPV) of an examination deemed positive for a nodule of 4 to 6 mm stands at 0.5%, increasing the threshold to 6 mm might act to increase the PPV by a factor of 1.8 (7.2% at 6 mm vs 3.8% at 4 mm) without significantly affecting the sensitivity to detect cancer. Given that the average risk of cancer in solid nodules smaller than 6 mm in patients at high risk is less than 1%, it is reasonable to assume an even lower risk in a patient with low clinical risk.

According to the risk categories proposed by the American College of Chest Physicians (ACCP), low risk, which corresponds to an estimated risk of cancer of less than 5%, is associated with young age, less smoking, smaller nodule size, regular margins, and location in an area other than the upper lobe.

Supporting evidence
  • CT screening for lung cancer: alternative definitions of positive test result based on the national lung screening trial and international early lung cancer action program databases. Yip R1, Henschke CI, Yankelevitz DF, Smith JP.Radiology. 2014 Nov;273(2):591-6. 2014 Jun 19
  • Gould MK, Donington J, Lynch WR, et al. 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. doi:10.1378/chest.12-2351
  • Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017
  • Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017
  • National Lung Screening Trial Research Team Aberle DR, Adams AM, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med 2011;365:395-409
  • Performance of ACR Lung-RADS in a Clinical CT Lung Screening Program McKee, Brady J. et al. Journal of the American College of Radiology, Volume 12, Issue 3, 273 - 276
How this list was made How this list was made

In 2018 The Royal Australasian College of Physicians worked with a Lead Fellow nominated by The Thoracic Society of Australia and New Zealand (TSANZ) to review evidence for 12 paediatric thoracic recommendations on low-value care in paediatric thoracic medicine. These recommendations were the subject of email discussions and deliberation by members of the Paediatric Special Interest Group (SIG) of the TSANZ. They were further discussed at a workshop held at a meeting of the Asia Pacific Society of Respirology in 2017, which included TSANZ members. Based on the feedback provided at this workshop and through email discussions with members of the SIG, four were removed and two of the original 12 were considered for inclusion in the final recommendations with overwhelming support. Members of the Paediatric SIG were then invited to choose three out of the remaining six through an email based poll. This served as the basis for final recommendations, which were further refined and developed through successive drafts based on the input of the Lead Fellow, the results of consultation with other specialty groups and the views of the TSANZ Board.

In 2020 TSANZ worked with RACP’s Policy & Advocacy team as part of the Evolve program to develop a long list of low-value practices and interventions that pertain to the specialty. Through extensive research and redrafting under the guidance of the TSANZ Central Office and members of the TSANZ Board, the list was condensed to the top-5 recommendations for reducing low-value practices in adult thoracic medicine. After several rounds of internal consultations and revisions, the list of recommendations was subject to an extensive review process that involved key College societies with an interest in or professional engagement with thoracic medicine.

Per usual processes, the recommendations were then consulted with other medical colleges through Choosing Wisely Australia. Feedback received in the consultations led to further work and refinements by Policy & Advocacy and TSANZ, which approved these top-5 recommendations. 

Download TSANZ Recommendations