Bronchial Washing Fluid Versus Plasma and Bronchoscopy Biopsy Samples for Detecting Epidermal Growth Factor Receptor Mutation Status in Lung Cancer

Zhang X, Li C, Ye M, Hu Q, Hu J, Gong Z, Li J, Zhao X, Xu Y, Zhang D, Hou Y and Zhang X (2021).

Oncol. 11:602402. doi: 10.3389/fonc.2021.602402

What is the key question?

  • Bronchial washing fluid (BWF) is quickly and easily collected at bronchoscopy and may provide answers to the diagnosis in patients with lung cancers. The question has arisen about its utility for molecular markers in lung cancer diagnosis.
  • This study investigated whether samples could be relied upon to provide suitable material for molecular analyses, comparing bronchial washings, endobronchial biopsies and plasma samples in patients with lung cancer.
  • Samples for washings were collected directly through the bronchoscope or through a guide sheath and paired with endobronchial and plasma samples in 110 patients with lung camncer. EGFR mutations were assessed using polymerase chain reaction (PCR) on all samples. Histology was considered standard reference.

What is the bottom line?

  • When compared to histology samples, sensitivity, specificity and concordance rate of EGFR mutation in BWF in this study was 92.5%, 100% and 97.9% respectively. BWF compared favourably to against plasma samples and histology samples with higher sensitivity than both other types (100% vs 62.5% and 77.5% respectively – although the numbers in the plasma group were small). Several factors influenced the diagnostic yield including diameter of the target lesion and the degree of contact with BWF.

Why read on?

  • These results suggest that BWF may be a viable option for testing the presence of EGFR mutations in patients with lung cancers. BWF may provide additional diagnostic help in such patients, especially where the EGFR test result is equivocal. This study also found results from BWF were returned much faster than histological sample results. These results support the viability of BWF as a diagnostic tool although further work is required.