Speaker's Highlight

• Don Sin University of British Columbia, St. Paul Hospital (Canada)
  Kenneth R. Chapman Toronto General Hospital Research Institute (Canada)
• Parameswaran Nair McMaster University (Canada)
  Carolyn Calfee UCSF (U.S.A.)
• Gregory P. Downey University of Colorado School of Medicine (U.S.A.)
  David A. Schwartz University of Colorado School of Medicine (U.S.A.)
• Neil Schluger Tuberculosis Control Branch, California Department of Public Health (U.S.A.)
  Nick Kim Critical Care & Sleep Medicine, University of California San Diego (U.S.A.)
• Nicola Hananiah Baylor College of Medicine (U.S.A.)
  Jae-Joon Yim Seoul National University College of Medicine (Republic of Korea)
• Koichiro Asano Tokai University School of Medicine (Japan)
  Diahn-Warng Perng Taipei Veterans General Hospital (Taiwan)
• Konstantinos Kostikas University of Ioannina (Greece)
  Karin Klooster University Medical Center Groningen (Kingdom of the Netherlands)

• Advances in Sputum Induction for Lung Cancer Cytology

  Lung cancer remains the leading cause of cancer-related death in Australia, claiming more than 8,500 lives each year according to Cancer Australia. Early detection continues to be the single biggest factor influencing survival, yet many diagnoses still occur at an advanced stage. Sputum induction offers a non-invasive, well-tolerated method for sampling the lower airways, and recent refinements in cytology have substantially expanded its diagnostic reach.

  Clinicians across Australian tertiary centres and regional hospitals are revisiting sputum induction as a first-line or complementary tool, particularly where bronchoscopy is delayed or contraindicated. With new molecular assays, automated screening platforms, and clearer national protocols, the technique has shifted from a basic cytology test to a sophisticated component of thoracic diagnostics.

  Feature	Sputum induction	Bronchoscopy	Liquid biopsy	Core needle biopsy
  Invasiveness	Low	Moderate	Low	High
  Approximate cost (AUD)	200–400	2,000–5,000	500–1,500	1,500–3,000
  Sensitivity for central lesions	Moderate	High	Low–moderate	High
  Suitability for molecular testing	Improving rapidly	Excellent	Good	Excellent
  Patient tolerance	Excellent	Moderate	Excellent	Poor
  Medicare rebate availability	Yes (pathology item)	Yes	Limited	Yes

  How sputum induction works and where it fits

  Sputum induction uses nebulised hypertonic saline to provoke coughing and loosen secretions from the peripheral airways. Patients rinse their mouth, inhale the aerosol for 10–15 minutes under supervision, and expectorate into a sterile container. A pathology lab then fixes, stains, and examines the sample, often with both conventional cytology and ancillary molecular testing.

  For Australian patients who live hours from the nearest tertiary hospital, the ability to produce a useful sample without sedation or a day procedure is a practical advantage. The technique is particularly valuable in regional clinics, mining communities with legacy asbestos exposure, and remote Indigenous health services where travel to a capital city is difficult. Many respiratory physicians now order sputum induction before, or instead of, more invasive investigations when imaging suggests a central or endobronchial lesion.

  Molecular and genomic advances

  Modern cytology no longer stops at identifying malignant cells. Sputum samples collected through induction can now yield enough tumour-derived DNA and RNA to run targeted next-generation sequencing panels. Australian pathology laboratories accredited by the National Association of Testing Authorities (NATA) routinely report on EGFR, ALK, ROS1, KRAS, and PD-L1 status from cytology specimens, in line with Thoracic Society of Australia and New Zealand (TSANZ) recommendations.

  Common actionable alterations identified in induced sputum:

  • EGFR activating mutations suitable for osimertinib therapy
  • ALK and ROS1 rearrangements for targeted kinase inhibitors
  • KRAS G12C variants eligible for newer selective inhibitors
  • PD-L1 expression scoring to inform immunotherapy decisions

  The ability to obtain a comprehensive molecular profile from a non-invasive sample shortens the turnaround between suspicion and treatment planning, an important gain when patients are already anxious about a possible cancer diagnosis and may be waiting weeks for a bronchoscopy slot in the public system.

  Standardisation, quality, and the role of the lab

  Reproducibility has been a historical weakness of sputum cytology. Cellular preservation varies with induction technique, saliva contamination, and transport conditions. Recent Australian guidelines encourage the use of Saccomanno's fixative or equivalent alcohol-based preservatives, two-slide preparation with both Papanicolaou and Diff-Quik stains, and rapid transport to the receiving pathology provider.

  Labs that perform high-volume respiratory cytology, such as those attached to Royal Melbourne Hospital, Peter MacCallum Cancer Centre, and the Queensland-based QIMR Berghofer, have published internal quality data showing sensitivity for centrally located tumours exceeding 70 percent when induction is performed by trained respiratory nurses. Continuous training, competency assessments, and participation in RCPA quality assurance programs help maintain these figures across public and private providers, including the large commercial networks that bulk-bill most of their work under Medicare.

  Access, equity, and the rural reality

  In remote Western Australia, the Northern Territory, and western Queensland, distance is a constant barrier to specialist diagnostics. The Royal Flying Doctor Service transports patients to tertiary centres when needed, but each flight costs the health system several thousand dollars and delays care. Sputum induction performed by a local GP or remote-area nurse, with the sample express-couriered to a metropolitan lab, can compress what is often a months-long diagnostic journey into a few weeks.

  Telehealth respiratory clinics now guide induction in real time, and several Primary Health Networks fund induction kits for Indigenous health workers in communities where lung cancer rates run well above the national average. Culturally safe communication matters here; clinicians who take time to explain the procedure in plain language, avoid jargon, and respect the patient's pace tend to get better samples and higher return rates for imaging follow-up.

  What helps regional programs succeed:

  • Designated coordinators at both the referring clinic and the receiving lab
  • Pre-labelled induction kits shipped by courier with same-day dispatch
  • Telehealth supervision by a respiratory scientist during the first attempts

  Emerging tools: AI, digital cytology, and what is next

  Automated digital scanners and machine-learning classifiers are starting to enter Australian cytology workflows. Algorithms trained on thousands of Papanicolaou-stained sputum slides can flag atypical cells for pathologist review, reducing screening fatigue and catching subtle abnormalities. Several Australian research groups are piloting cloud-based platforms that allow a cytologist in Perth to review a digital slide prepared from a sample collected in Broome or Cairns within hours of collection.

  Combination strategies are also gaining traction. Sputum induction paired with volatile organic compound analysis of exhaled breath, or with plasma ctDNA testing, can improve detection of peripheral tumours that traditional sputum cytology may miss. As evidence builds, the technique is likely to become a routine part of lung cancer screening pilots now being scoped in New South Wales and Victoria.

  For clinicians attending APSR 2022, the immediate practical step is to review the induction protocol used at their own institution and confirm that sputum samples are routinely sent for molecular testing when atypical cells are reported, using NATA-accredited pathology providers that operate under TSANZ-aligned standards.

  Richard Russell Nuffield Department of Clinical Medicine, University of Oxford (United Kingdom)
• Mona Bafadhel King’s College London (United Kingdom)
  David Jackson Guy’s and St Thomas’ Hospital, King’s College London (United Kingdom)
• James Chalmers University of Dundee (United Kingdom)
  David Price University of Aberdeen (United Kingdom)