Feasibility and Accuracy of Molecular Testing in Specimens Obtained with Small Biopsy Forceps: Comparison with the Results of Surgical Specimens

Abstract

Background: During bronchoscopy, small biopsy forceps are increasingly used for the diagnosis of peripheral pulmonary lesions. However, it is unclear whether the formalin-fixed paraffin-embedded specimens sampled with the small biopsy forceps are suitable for the determination of genotypes which become indispensable for the management decision regarding patients with non-small cell lung cancer. Objectives: The aim of this study was to evaluate the feasibility and accuracy of molecular testing in the specimens obtained with 1.5-mm small biopsy forceps. Methods: We examined specimens in 91 patients, who were enrolled in our previous 3 studies on the usefulness of thin bronchoscopes and given a diagnosis of non-small cell lung cancer by bronchoscopy with the 1.5-mm biopsy forceps, and then underwent surgical resection. An experienced pathologist examined paraffin-embedded specimens obtained by bronchoscopic biopsy or surgical resection in a blind fashion on epidermal growth factor receptor (EGFR) mutations, anaplastic lymphoma kinase (ALK) rearrangements and KRAS mutations. Results: Twenty-five (27%), 2 (2%) and 5 (5%) patients had an EGFR mutation, ALK rearrangement and KRAS mutation, respectively, based on the results in surgical specimens. EGFR, ALK and KRAS testing with bronchoscopic specimens was feasible in 82 (90%), 86 (95%) and 83 (91%) patients, respectively. If molecular testing was feasible, the accuracy of EGFR, ALK and KRAS testing with bronchoscopic specimens for the results with surgical specimens was 98, 100 and 98%, respectively. Conclusion: The results of molecular testing in the formalin-fixed paraffin-embedded specimens obtained with the small forceps, in which the genotype could be evaluated, correlated well with those in surgically resected specimens.

Molecular analysis of peripheral non‐squamous non‐small cell lung cancer sampled by radial EBUS

“…In this series of routinely processed samples, MAF appears similar to that reported in a previous study that used frozen brushing specimens for EGFR and KRAS testing, and was even higher in the second half‐period of the study (89%). These results are close to the reported molecular analysis from CT‐guided transthoracic sampling (TTNB), and to ultrathin bronchoscopy sampling with direct vision of the lesion . The increase in MAF in the second half‐period of the study is probably due to the higher number of biopsies performed per lesion, suggesting a clinical learning curve.…”

“…Several studies have investigated the adequacy of CT‐guided TTNB samples for molecular testing. The success rate of molecular analysis of EGFR mutation following TTNB has been reported as nearly 90% …”

“…One study using ultrathin bronchoscope and direct access to the tumour showed the feasibility of EGFR , KRAS and ALK analysis …”

Ultrathin Bronchoscopy with Multimodal Devices for Peripheral Pulmonary Lesions. A Randomized Trial

“…The high frequency seems to suggest that the volume of specimens is sufficient for genotyping of lung cancer or immunohistochemistry for definitive diagnosis in our clinical practice. In fact, we demonstrated high feasibility and accuracy for molecular testing in specimens obtained with the 1.5-mm biopsy forceps in our recent study (26).…”

The many facets of diagnostic bronchoscopy for pulmonary ground glass nodules

“…For non-surgical diagnosis of GGOs, especially those that are malignant, sufficient evaluation of tissue architecture had been emphasized. Although the use of large biopsy forceps seems to yield better for this purpose, size of biopsy forceps has been shown to not affect the diagnostic yield for PPLs (21). The same is true for size of the bronchoscope used.…”