Multidisciplinary Discussion in Interstitial Lung Diseases

Interstitial lung diseases (ILD) are challenging to the pulmonologist both in the diagnostic workup as well as in choosing the appropriate treatment. ILDs are diverse and heterogeneous. They include diseases with variable clinical presentations, radiological features, histopathology, and response to therapy. Moreover, these often present with overlapping features. In spite of extensive evaluation, ILDs remain unclassifiable in up to 10%–20% of cases.1 In this scenario, multidisciplinary discussion (MDD) has emerged as an indispensable element in ILD diagnosis and management. Recommended by multiple guidelines over the past two decades, MDD increases diagnostic accuracy, helps in deciding the optimum treatment, and aids in the follow-up of patients.2–5 This editorial summarizes the evolution of MDD in ILD, reviews evidence on its utility, and discusses future directions for its refinement. FROM HISTOLOGY TO MULTIDISCIPLINARY DISCUSSION Even before the first official recommendation by the American Thoracic Society (ATS) and European Respiratory Society (ERS) in 2002,2 MDD was found to be useful.6 Historically, surgical lung biopsy (SLB) was considered the gold standard for the diagnosis of ILD.7 Interobserver variability, limitations in reproducibility, and risks of the procedure created practical problems. Frequent disagreement among pathologists on ILD subtypes was high, especially when differentiating usual interstitial pneumonia (UIP) from nonspecific interstitial pneumonia (NSIP) pattern.8 Divergent diagnoses due to sampling errors were also reported.9 Moreover, a histopathologic UIP pattern may not always be related to idiopathic pulmonary fibrosis (IPF).10 The 2002 ATS/ERS classification of idiopathic interstitial pneumonias first recommended MDD for an integrated approach (clinical, radiological, and pathological).2 Subsequent guidelines advocated MDD as the gold standard for ILD diagnosis.3,4 The Fleischner statement reinforced it.11 CORE PARTICIPANTS IN MULTIDISCIPLINARY DISCUSSION Usually, the MDD team includes a pulmonologist, radiologist, and pathologist (preferably all with experience in ILD).12 A rheumatologist is included when autoimmune diseases are suspected.13 Other optional participants may include a thoracic surgeon, immunologist, physiotherapist, ILD specialist nurse, or a specialist in lung transplantation.12,13 DATA INTEGRATION Data from multiple sources are integrated by the MDD team. The variables evaluated at MDD are clinical history and examination, family history, pulmonary function tests, high-resolution computed tomography (HRCT) of the chest, serological testing including autoimmune markers, histopathology via SLB, or transbronchial lung cryobiopsy (TBLC), bronchoscopy, and bronchoalveolar lavage studies. MDD is an ongoing process. Hence, revision of the diagnosis may be allowed as clinical and other features change over time.14 DIAGNOSTIC AND THERAPEUTIC IMPACT The clinical value of MDD is supported by evidence. Compared to individual physician assessment, MDD increases diagnostic confidence, improves interobserver agreement, reduces the number of unclassifiable ILD, and influences therapeutic decisions.1,13,15 Various studies have shown its benefit.12,13,16 MDD facilitates therapeutic selection, as in: (1) antifibrotic therapy for IPF and progressive pulmonary fibrosis, (2) immunosuppressive therapy for ILD associated with connective tissue diseases ILD (CTD-ILD) and NSIP, and (3) no treatment in some cases.14,15 MDD takes a decisive role in determining the need for SLB and in deciding the choice between SLB and TBLC.14 It diagnoses IPF and CTD-ILD with good agreement, but agreement is only fair for idiopathic NSIP and hypersensitivity pneumonitis.14 MDD results in a change in diagnosis in 40%–53% of cases.17,18 MULTIDISCIPLINARY DISCUSSION IN LONGITUDINAL CARE ILDs often have a dynamic course. MDD facilitates diagnostic refinement by incorporating new clinical data, repeat imaging, and serologies. MDD also plays a key role in the escalation, de-escalation, and modification of treatment regimens.12,14 Limitations There is no global standard for MDD.12 MDDs are usually concentrated in teaching institutions.1 Inter-MDD variability has also been reported.19 FUTURE The following approaches can be pursued to enhance the MDD process. (1) Its core elements (mandatory participants, datasets to be reviewed, and the frequency of meeting) are to be standardized.12 (2) Virtual platforms and regional ILD networks can provide access to more patients.12 (3) New technologies such as artificial intelligence tools and machine learning-based HRCT interpretation may improve the MDD team.14 CONCLUSION MDD is the gold standard for the diagnosis and management of ILDs. It provides individualized care for complex cases, decreases diagnostic confusion, and leads to better treatment choices. The MDD process must evolve with emerging tools and evidence. Robust, accessible, and standardized MDD frameworks are crucial for improving outcomes for patients with ILD. In the current edition of this journal, Dr. Vivek N Vijay and colleagues examine the diagnostic agreement between MDD-based assessments and histopathologic confirmation in ILD patients.