Utility of cell blocks obtained by catheter aspiration via a guide sheath during endobronchial ultrasonography

Utility of bronchoscopically obtained frozen cytology pellets for next-generation sequencing

BACKGROUND

Next-generation sequencing (NGS) is essential for lung cancer treatment. It is important to collect sufficient tissue specimens, but sometimes we cannot obtain large enough samples for NGS analysis. We investigated the yield of NGS analysis by frozen cytology pellets using an Oncomine Comprehensive Assay or Oncomine Precision Assay.

METHODS

We retrospectively enrolled patients with lung cancer who underwent bronchoscopy at Kobe University Hospital and were enrolled in the Lung Cancer Genomic Screening Project for Individualized Medicine. We investigated the amount of extracted DNA and RNA and determined the NGS success rates. We also compared the amount of DNA and RNA by bronchoscopy methods. To create the frozen cytology pellets, we first effectively collected the cells and then quickly centrifuged and cryopreserved them.

RESULTS

A total of 132 patients were enrolled in this study between May 2016 and December 2022; of them, 75 were subjected to frozen cytology pellet examinations and 57 were subjected to frozen tissue examinations. The amount of DNA and RNA obtained by frozen cytology pellets was nearly equivalent to frozen tissues. Frozen cytology pellets collected by endobronchial ultrasound-guided transbronchial needle aspiration yielded significantly more DNA than those collected by transbronchial biopsy methods. (P < 0.01) In RNA content, cytology pellets were not inferior to frozen tissue. The success rate of NGS analysis with frozen cytology pellet specimens was comparable to the success rate of NGS analysis with frozen tissue specimens.

CONCLUSIONS

Our study showed that frozen cytology pellets may have equivalent diagnostic value to frozen tissue for NGS analyses. Bronchial cytology specimens are usually used only for cytology, but NGS analysis is possible if enough cells are collected to create pellet specimens. In particular, the frozen cytology pellets obtained by endobronchial ultrasound-guided transbronchial needle aspiration yielded sufficient amounts of DNA.

TRIAL REGISTRATION

This was registered with the University Medical Hospital Information Network in Japan (UMINCTR registration no. UMIN000052050).

Liquid biopsy for the detection of resistance mutations to ROS1 and RET inhibitors in non-small lung cancers: A case series study

Liquid biopsy can identify gene alterations that are associated with resistance to fusion gene-targeted treatments. In this study, we present three cases of advanced non-small cell lung cancer (NSCLC) harboring gene fusions; cell-free DNA (cfDNA) was used to assess the resistance mutations. A patient with MET amplification underwent RET-fusion NSCLC treatment with selpercatinib. A patient with ROS1 G2032R underwent ROS1-fusion NSCLC treatment with crizotinib. A patient who underwent ROS1-fusion NSCLC treatment with crizotinib harbored no somatic mutations. This case series shows that cfDNA analysis can identify potentially actionable genomic alterations, after disease progression, in targeted therapy for fusion genes. TRIAL REGISTRATION: The study was registered in the UMIN Clinical Trial Registry (UMIN 000017581).

Yield of tumor samples with a large guide-sheath in endobronchial ultrasound transbronchial biopsy for non-small cell lung cancer: A prospective study

Background

Adequate tumor tissue is required to make the best treatment choice for non-small cell lung cancer (NSCLC). Transbronchial biopsy (TBB) by endobronchial ultrasonography with a guide sheath (EBUS-GS) is useful to diagnose peripheral lung lesions. The data of tumor cell numbers obtained by two different sizes of GSs is limited. We conducted this study to investigate the utility of a large GS kit to obtain many tumor cells in patients with NSCLC.

Methods

Patients with a peripheral lung lesion and suspected of NSCLC were prospectively enrolled. They underwent TBB with a 5.9-mm diameter bronchoscope with a large GS. When the lesion was invisible in EBUS, we changed to a thinner bronchoscope and TBB was performed with a small GS. We compared the tumor cell number prospectively obtained with a large GS (prospective large GS group) and those previously obtained with a small GS (small GS cohort). The primary endpoint was the tumor cell number per sample, and we assessed characteristics of lesions that could be obtained by TBB with large GS.

Results

Biopsy with large GS was performed in 55 of 87 patients (63.2%), and 37 were diagnosed with NSCLC based on histological samples. The number of tumor cells per sample was not different between two groups (658±553 vs. 532±526, estimated difference between two groups with 95% confidence interval (CI); 125 (-125–376), p = 0.32). The sample size of the large GS group was significantly larger than that of the small GS cohort (1.75 mm² vs. 0.83 mm², estimated difference with 95% CI; 0.92 (0.60–1.23) mm², p = 0.00000019). The lesion involving a third or less bronchus generation was predictive factors using large GS.

Conclusions

The sample size obtained with large GS was significantly larger compared to that obtained with small GS, but there was no significant difference in tumor cell number. The 5.9-mm diameter bronchoscope with large GS can be used for lesions involving a third or less bronchus generation.

Central papillary adenoma of the lung diagnosed in a bronchoscopy-guided FNA: Cytological and histological characterization of this rare entity

Pulmonary papillary adenoma (PA) is an unusual tumor with only 32 reported cases to date. We present a case of a 69-year-old man, a smoker from the age of 12, with a central mass in the pulmonary left lower lobe identified in a PET-CT scan. Microscopical analysis of the Fine Needle Aspiration (FNA) samples showed fragments of a tumor comprised of abundant papillary structures lined by a monolayer of cytologically bland columnar to cuboidal epithelial cells. The immunohistochemical stains were positive for CK7, TTF-1 and EMA in the epithelial cells, and negative for MYC. Based on the imaging tests, histological features and immunohistochemical profile, the tumor was diagnosed as pulmonary PA. The cytologic and histologic features of this rare entity are described in detail and the value of FNA as an essential presurgical diagnostic procedure is emphasized.

Contribution of cell blocks obtained through endobronchial ultrasound-guided transbronchial needle aspiration for the determination of lung cancer subtypes

INTRODUCTION

It is crucial to diagnose the subtype of lung cancer quickly and accurately for effective therapy. Conventional cytology staining sometimes provides limited information, and additional tissue is often required to diagnose lung cancer. Cell blocks (CB) recovered during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) increases the diagnostic accuracy of the procedure and the likelihood of additional valuable histochemical and immunohistochemical staining.

OBJECTIVES

To evaluate the diagnostic significance of smears and CBs for lung cancer subtypes METHODS: Records of patients who underwent EBUS-TBNA between July 2014 and December 2016 for lung cancer diagnosis and/or staging were retrospectively analysed.

RESULTS

The study included 156 patients and 232 LNs diagnosed as malignancies. Twenty-seven patients were diagnosed with small cell lung cancer (SCLC), and 129 were diagnosed with non-small cell lung carcinoma (NSCLC) (68 patients adenocarcinoma, 36 patients squamous cell carcinoma, 23 patients NSCLC if not otherwise stated, 1 patient large cell carcinoma and 1 patient pleomorphic carcinoma). The mean age was 60.5 ± 10.2 years, and 74.5% of the patients were males. The diagnostic rate for CBs was 231/232 (99.6%) and was 206/232 (88.8%) (P < .001) for smears. The diagnostic rate for SCLC was 37/39 (94.9%) for smears and 39/39 (100%) for CB (P < .001). For NSCLC, it was 169/193 (87.6%) for smears and 192/193 (99.5%) for CB (P < .001).

CONCLUSIONS

Cell-block preparation after an EBUS-TBNA is a simple method that provides important additional information related to lung cancer for morphological analyses.