Cryotherapy is an evolving therapeutic and diagnostic tool used in bronchoscopy [
The literature review revealed that fluoroscopic guidance was used in bronchoscopic cryobiopsy [
This retrospective study was performed at Chang Gung Memorial Hospital, Linkou branch, a tertiary referral medical center in Taiwan. This study enrolled patients aged more than 20 years who received bronchoscopy examinations with cryotechnology between July 2014 and June 2016, and their data were collected through medical chart review. Patients with endobronchial mass who received cryotherapy through flexible bronchoscope were excluded. The clinical data of the study patients, including age, sex, pathological diagnosis, specimen size, procedure-related complications (i.e., pneumothorax, major bleeding, or respiratory failure), and outcomes, were retrospectively reviewed and analyzed.
Bronchoscopy was performed using a flexible bronchoscope (BF-P240 or BF-40; Olympus, Tokyo, Japan), and during the procedure, patients received local anesthesia with 2% xylocaine. A 20 MHz miniature radial probe (UM-S20-S20R; Olympus) and an ultrasound unit (Endoscopic Ultrasound System, Olympus) were also used. All patients underwent chest computed tomography (CT) before the bronchoscopy procedure, and the radial EBUS probe was inserted into the target segmental bronchus determined by the bronchoscopists. The echoic features of the peripheral parenchymal lesions were recorded [
Cryobiopsy was performed using a 1.9 mm flexible cryoprobe (Erbokryo CA, Erbe, Germany) with carbon dioxide as the cryogen. A temperature of approximately −70°C was achieved at the probe tip. The biopsy sites were determined by the bronchoscopists according to the CT and EBUS findings. The probe cooling time was approximately 4–6 seconds. After cooling, the cryoprobe was immediately retracted using the bronchoscope. The frozen biopsy specimens were then thawed in normal saline and fixed in formalin. The bronchoscope was reintroduced to confirm airway status [
Continuous variables are expressed as the mean ± standard deviation and categorical variables as the frequency and percentage. All statistical analyses were performed using MedCalc, version 12.5 (MedCalc Software, Ostend, Belgium). Two-tailed
During the study period, 101 patients underwent bronchoscopy examinations with cryotechnology. Ninety patients with endobronchial tumors were excluded from this study. Thus, this study included 11 patients with a mean age of 61.1 ± 13.8 years (Table
Baseline characteristics of patients receiving cryobiopsy (
Characteristic | Value |
---|---|
Age | 61.1 ± 13.8 |
Sex (female), |
6 (54.5) |
Outpatient, |
7 (63.6) |
Body mass index | 25.3 ± 6.7 |
Prebiopsy diagnosis | |
Interstitial lung disease, |
6 (54.5) |
Peripheral parenchymal lesions, |
5 (45.5) |
Pulmonary function tests | |
FEV1 percentage predicted (%) | 63.9 ± 32.1 |
FVC percentage predicted (%) | 61.9 ± 24.5 |
A 73-year-old female received cryobiopsy from right middle lobe showing correlation among the axial CT image, radial endobronchial ultrasound (EBUS) image, and histopathologic finding from biopsy. (a) Axial CT image in lung window demonstrated a right hilar mass with partial obstructive pneumonitis and numerous tiny ipsilateral lung nodules. (b) EBUS showed a heterogeneous echogenicity lesion with a continuous margin, and the probe was within the lung lesion (eccentric radial EBUS image). (c) Histologic specimen of the biopsy showed invasive nests of adenocarcinoma (hematoxylin and eosin staining, 200x).
A 66-year-old female received cryobiopsy from lingula showing correlation among the axial CT image, endobronchial ultrasound (EBUS) image, and histopathologic finding from biopsy. (a) Axial CT image in lung window demonstrated ground-glass opacities in peribronchial distribution and dependent atelectasis in the bilateral dependent lung. The image appearance is nonspecific with several possible differential diagnoses, including atypical pneumonia, acute interstitial pneumonitis, nonspecific interstitial pneumonitis, and/or pulmonary edema. (b) EBUS showed heterogeneous echogenicity, along with linear–discrete air bronchogram. (c) Histologic specimen of the biopsy revealed interstitial homogenous fibrosis and chronic inflammation (hematoxylin and eosin staining, 200x).
The number of cryobiopsies ranged from 1 to 3. In the histological biopsies, the mean specimen diameter was 0.53 ± 0.23 cm, and the mean biopsy area was 0.20 ± 0.19 cm2. Two patients had no histopathological diagnosis (negative for malignancy), and the other nine patients had pathological diagnoses. The biopsy sites and pathological diagnoses are provided in Table
Pathological diagnoses of patients receiving cryobiopsy (
Pathology | Number |
---|---|
Biopsy location | |
Right middle lobe | 5 |
Right lower lobe | 3 |
Left upper lobe | 1 |
Lingula | 2 |
Pathological diagnosis | |
Adenocarcinoma | 3 |
Interstitial fibrosis | 5 |
Chronic inflammation | 1 |
Negative for malignancy | 2 |
Few studies have used radial EBUS-guided cryobiopsy without fluoroscopy for peripheral lesions. An important finding of our study is that radial EBUS-guided cryobiopsy is useful to biopsy peripheral lung lesions at institutions without fluoroscopy equipment. The biopsy specimen retrieved was adequate, and no major complications were noted.
Cryotechnology is useful and safe for diagnosing and treating central airway lesions [
The procedure of cryobiopsy through a flexible bronchoscope varies across studies, and the cooling time and the cryoprobe size have not been standardized [
The diagnostic yield rate of transbronchial biopsy is influenced by several factors, including lesion size, lesion location, bronchus sign, rapid on-site evaluation, prevalence of disease in the patient cohort, or navigation systems [
Our study has several limitations. First, this study was conducted in a single tertiary referral medical center; thus, the generalizability of the findings may be limited. Bronchoscopists have a high level of experience for interventional bronchoscopy, including cryotechnology and transbronchial biopsy. Second, the study was retrospective, and the inclusion of patients receiving bronchoscopic cryobiopsy might be highly selective. We had no standard procedure protocol for patient selection. Third, the sample size was small, because transbronchial cryobiopsy was an alternative method to surgical biopsy for diagnosis of interstitial lung disease.
EBUS-guided cryobiopsy is a feasible technique to biopsy peripheral lung parenchymal lesions in selected cases to obtain a large specimen at institutions without fluoroscopy equipment. This study provided some rationale for further studies examining the impact of fluoroscopy.
This study was conducted in accordance with the amended Declaration of Helsinki. This study was approved by the institutional review boards at Chang Gung Medical Foundation (IRB no. 201600902B0). All individual information was delinked.
The authors declare that they have no conflicts of interest.