The relevance of bronchoalveolar lavage fluid analysis for lung cancer patients

ABSTRACT

Introduction: Lung cancer is a serious malignant disease with poor prognosis. The methods for improving early recognition and markers of predictive value are widely investigated. Bronchoalveolar lavage (BAL) is a valuable method of respiratory tract investigation. Currently, BAL is rarely used for tumor diagnosis, but for ruling out differential diagnosis, due to its poor sensitivity. The new indication for BAL fluid analysis is evaluation of local immune reaction in lung cancer patients and description of tumor microenvironment (TME). A literature search was performed in bibliography bases from the time of the introduction of BAL in the diagnosis of lung diseases. We analyzed our prior original studies with the bibliography.

Area covered: The usefulness of BAL in the diagnosis of peripheral spread of malignant diseases and in the evaluation of TME in lung cancer, as well as a role of BAL in the diagnosis of checkpoint inhibitor pneumonitis is presented. Commentary concerning methodology of BALF analysis in lung cancer is included.

Expert opinion: It seems that in the near future BAL will find an important place in the evaluation of lung cancer TME in two aspects. The first could be characteristic of immune reaction by analysis of immune cells and mediators and the second cancer molecular characteristic by free DNA and exosomes analysis.

KEYWORDS:

• BAL
• lung cancer
• tumor environment

Article highlights

• Bronchoalveolar lavage (BAL) is a useful method of respiratory tract investigation

• The issue is to follow the recommendations concerning BAL performing and processing of the BAL fluid

• BAL fluid (BALF) contains immune cells: macrophages, lymphocytes, neutrophils, and eosinophils, which count is constant in healthy but is altered in different lung diseases

• The immunophenotyping of BALF cells is possible by flow cytometry

• Analysis of BALF (cells and mediators) in lung cancer provides valuable information about character of the tumor microenvironment (TME)

• The differentiation of immune active ‘hot’ vs. ‘cold’ TME is predictive for lung cancer immunotherapy, the features of these TME features by BALF analysis are possible

• BAL is good methods for differential diagnosis of checkpoint inhibitors pneumonitis

• In lung cancer diagnosis BAL is an equivalent for other methods of peripheral tumors recognition but with lower sensitivity

• There is an important role of BAL in the differential diagnosis of diffuse lung infiltrations of malignancy; among them, lymphoproliferative diseases, multifocal adenocarcinoma, and lymphangitic carcinomatosis could be confirmed.

Acknowledgments

The author thanks Kinga Sadej-Sobolewska for English language correction.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.