The Journal of Association of Chest Physicians

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 9  |  Issue : 2  |  Page : 53--58

Diagnostic accuracy, indications, and negative predictive value of EBUS-TBNA procedure: retrospective observational study from a referral cancer institute


Kunal Luthra1, Jyoti Singh2,  
1 Assistant Professor, Department of Pulmonology, Rajiv Gandhi Superspeciality Hospital, New Delhi, India
2 Senior Resident, Department of ENT, Chacha Nehru Bal Chikitsalaya, Delhi, India

Correspondence Address:
Dr. Kunal Luthra
Assistant Professor, Department of Pulmonology, Rajiv Gandhi Superspeciality Hospital, New Delhi 110093
India

Abstract

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is minimally invasive procedure for the evaluation of mediastinal mass and lymph nodes. Aim: This study was conducted as an internal audit to determine diagnostic accuracy, false-negative rate of a costly, invasive procedure EBUS-TBNA performed under conscious sedation or deep/general anesthesia. Methods: Forty-nine patients who underwent EBUS-TBNA procedure at our institute were included in this retrospective study. Sensitivity, diagnostic accuracy, and negative predictive values were calculated considering clinical radiological assessment till 6 months as gold standard. Results: Forty-nine patients (27 females and 22 males) with mean age of 47.88 years underwent EBUS-TBNA during a period of 8 months. The most common indication was extrathoracic malignancy metastasis in 26 (53.1%) patients. EBUS-TBNA was performed for diagnosing malignancy lung in 11 patients, granulomatous disease in 8 patients, and mediastinal mass in 4 patients. A total of 74 nodes were sampled in 49 patients. Adequate samples were obtained in 46 patients (93.9%). Diagnostic accuracy was overall 91.8%. There were no procedure-related complications or mortality noted in any patient. Out of 17 negative cases, false negatives were 4, and negative-predictive value was 76.5%. The diagnostic accuracy, sensitivity, and negative predictive value were higher in procedures performed under deep sedation/general anesthesia. Conclusion: Diagnosing extrathoracic malignancy metastasis and malignancy lung are major indications for the EBUS-TBNA procedure at our institute. The diagnostic accuracy overall was 91.8%. The negative-predictive value, diagnostic accuracy, and sensitivity were higher for procedures performed under deep sedation/general anesthesia versus conscious sedation.



How to cite this article:
Luthra K, Singh J. Diagnostic accuracy, indications, and negative predictive value of EBUS-TBNA procedure: retrospective observational study from a referral cancer institute.J Assoc Chest Physicians 2021;9:53-58


How to cite this URL:
Luthra K, Singh J. Diagnostic accuracy, indications, and negative predictive value of EBUS-TBNA procedure: retrospective observational study from a referral cancer institute. J Assoc Chest Physicians [serial online] 2021 [cited 2021 Dec 7 ];9:53-58
Available from: https://www.jacpjournal.org/text.asp?2021/9/2/53/323090


Full Text



Key messages: This study adds on to the existing data on diagnostic accuracy, sensitivity of the EBUS-TBNA procedure overall, and impact of sedation protocol on accuracy and negative predictive value.

 INTRODUCTION



Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is minimally invasive technique that utilizes fine gauze (G) needle to sample the mediastinum and lung. It is a novel procedure that has incorporated the use of ultrasound imaging and bronchoscope together to move beyond the pulmonary parenchyma, thus increasing the safety as needle aspiration procedures are performed under real-time ultrasound imaging. EBUS-TBNA is being used for diagnosing pulmonary malignancies, extrapulmonary metastatic carcinoma, benign lesions, and other nonepithelial tumors (lymphoma, leukemia, thymic neoplasm, mesenchymal tumors).[1]

Either 22G or 21G EBUS-TBNA needle can be used for the procedure, and there is no difference in diagnostic yield and sample adequacy in procedures performed with 22G or 21G needle.[2]

The EBUS-TBNA procedure can be carried out under moderate or deep sedation, or under general anesthesia. The decision on sedation should be based on patient preference and duration of anticipated procedure. The diagnostic yield and safety profile are comparable with moderate versus deep sedation or general anesthesia.[3],[4]

This study was conducted as an internal audit to determine diagnostic accuracy, false negative rate of a costly invasive procedure EBUS-TBNA performed under conscious sedation or deep/general anesthesia.

 SUBJECTS AND METHODS



A retrospective observational study of patients who underwent EBUS-TBNA procedure over an 8-month period (January 2018 to August 2018) was conducted at department of chest medicine in our institute. Informed written consent for the procedure was obtained from all the patients. Computed tomography scan of the thorax, prothrombin time, platelet count, viral markers, human immunodeficiency virus, hepatitis B surface antigen, antihepatitis C virus, and other relevant investigations as appropriate for the EBUS-TBNA procedure were performed in patients.

Procedure

The EBUS-TBNA was performed on outpatient or inpatient basis under conscious sedation, deep sedation, or general anesthesia. Premedication included nebulization with lignocaine 2% solution, and intravenous injection of 0.2 mg glycopyrrolate. Local anesthesia was augmented by spray of 10% lignocaine on the posterior pharynx and spray as you go with 2% lignocaine solution. Procedures under conscious sedation were performed using intravenous midazolam (2–3 mg average dose) in endoscopy room. The procedure under deep sedation and general anesthesia were performed in major operation theater using various drugs (propofol, fentanyl, vecuronium, and inhalation agents) in combination as decided by anesthetist. An endotracheal tube (minimum internal diameter 8.5 mm) or laryngeal mask airway (minimum size 4) was used when procedures were carried out in general anesthesia.

Olympus BF type UC180F convex probe scope (Olympus Medical Systems, Japan) was used through oral route after bite block insertion for the procedure. Vizishot EBUS-TBNA needle 21G or 22G was used to sample the lymph nodes. Samples were also taken while applying suction following nodal puncture using negative pressure syringe provided with the TBNA needle kit. Air-dried and alcohol-fixed slide smears were prepared from the sample aspirated. Tissue core obtained was sent for analysis. In suspected tuberculosis cases, samples were sent for acid-fast bacilli stain and cartridge-based nucleic amplification test. Minimum three passes were taken from the mediastinal node or mass.

Data analysis

Samples were considered adequate: atypical cells or numerous lymphocytes observed on high power field. EBUS-TBNA was considered diagnostic: specific diagnosis was made (positive result of malignancy, metastasis, granulomas, AFB staining, or gene expert) or if negative results were confirmed as true negative by clinical and radiological follow up till 6 months.

In negative or nondiagnostic result, patients were managed according to clinical features, radiological findings, and other investigations such as tuberculin test, serum Angiotensin-Converting Enzyme (ACE) levels, and final diagnosis was based on treatment response, or repeat EBUS-TBNA procedure.True positive: All positive TBNA results were considered as true positive.True negative: Negative TBNA result, and decrease in size on follow-up.False negative: Negative initial report, and increase in size on follow up. Specific diagnosis made subsequently with repeat EBUS-TBNA or other procedure.False positive: Not considered.

Statistical analysis was performed using SPSS 17.0 version (SPSS statistics for Windows, Version 17.0, Chicago: SPSS Inc.).

 RESULTS



The mean age of study group was 47.88 years (range 14–72, standard deviation 13.75). Out of 49 patients, 22 were males and 27 were females. The most common presenting complaint was cough (44.9%) followed by chest pain (24.5%), weight loss (16.3%), and shortness of breath (14.3%) [Table 1].{Table 1}

Total 74 nodes were sampled in 49 patients. Most commonly sampled lymph node was subcarinal (55.1%) followed by right lower paratracheal lymph node (40.8%), right upper paratracheal lymph node (12.2%). Adequate samples were obtained in 46 patients (93.9%). There were no procedure-related complications or mortality noted in any patient. The EBUS-TBNA procedure was diagnostic in 45 patients (91.8%); true positive in 32 and true negative in 13 [Table 2].{Table 2}

Malignancy lung (metastasis) was diagnosed in 15 patients. The most common malignancy was small-cell carcinoma followed by carcinoma not otherwise specified (NOS), and adenocarcinoma. Extrathoracic malignancy (metastasis) was reported in 8 out of 26 patients (30.76%). Other diagnoses obtained were tuberculosis in seven patients, sarcoidosis in one, and benign epithelial neoplasm in one patient each [Table 3].{Table 3}

Necrotizing granulomas and suggestive clinicoradiologic profile were diagnosed as tuberculosis and started on antitubercular therapy. Non-necrotizing granulomas along with supportive clinical settings, such as raised angiotensinogen-converting enzyme levels and mantoux test negative, were diagnosed as sarcoidosis and started on steroid treatment. There were two cases diagnosed as sarcoidosis based on clinical assessment, started on steroid treatment and subsequently calculated as false negative on EBUS-TBNA.

Repeat TBNA was performed in one patient based on follow up for diagnosing metastatic node. Video-assisted thoracoscopic surgery (VATS)-guided biopsy was performed in one patient for the final diagnosis [Table 4].{Table 4}

 DISCUSSION



The EBUS-TBNA is minimally invasive, highly sensitive, specific, and safe procedure for mediastinal lymph-node sampling in staging of malignancy and diagnosing other thoracic diseases such as tuberculosis and sarcoidosis. It can be performed via endobronchial or esophagus route. A positive pathologic diagnosis with EBUS can be considered as true positive, but in negative reports, surgical staging or clinical follow up is recommended.[5],[6] In our study, we considered clinical-radiological follow up for 6 months in EBUS-TBNA negative cases as gold standard.

Majority of cases were performed to detect metastasis from extrapulmonary malignancies or to diagnose malignancy lung in which other conventional approaches, such as endobronchial biopsy or transthoracic needle aspiration, were not possible. There was no procedure performed for preoperative lung cancer staging in our study, as our center is referral cancer institute where majority of the lung cancer patients are in advance stage referred for chemotherapy and radiotherapy. Similar finding was noted in other studies from India as well.[7],[8]

Around 27 (55.10%) procedures were performed in deep sedation and general anesthesia at our institute. Our center is tertiary care cancer institute where 600 bronchoscopies and 80 EBUS procedures are performed yearly. A dedicated anesthesia team and postoperative ward for pulmonary procedures are available at our institute, unlike other public-sector hospitals in our country, where most of the cases are performed in conscious or moderate sedation only.[8]

The diagnostic accuracy, sensitivity, negative predictive value of procedure performed in deep/general anesthesia were 96.3%, 93.8%, and 91.8%, respectively [Table 5].{Table 5}

The higher diagnostic accuracy, negative predictive value in procedures performed under deep sedation or general anesthesia compared to moderate sedation was reported in other study too.[9] Out of 26 patients of extrathoracic malignancies in our study, nodal metastasis was detected in 8 (30.76%). Similar finding was observed in other study too.[10]

Small-cell carcinoma manifests as mediastinal or hilar lymphadenopathy, mostly central in location thus accessible with EBUS technique rather than conventional bronchoscopy.[11] EBUS is useful in early diagnosis of central masses. In our study, 40% of lung malignancy diagnosed was small-cell carcinoma.

The complication rate reported from a systemic review on EBUS-TBNA procedure was 0.05% for serious adverse events, and 0.10% for minor adverse events.[12] In our study, there were no serious adverse events. Minor complications were observed in four patients; bleeding from puncture site in two patients controlled with instillation of 1 mg adrenaline and severe coughing during the procedure in two patients that leads to termination of procedure. The EBUS-TBNA was performed eventually under general anesthesia in patients with severe coughing during the procedure. Overall, it is a safe procedure.

The limitations of our study are as follows: Mediastinoscopy was not available at our institute. The follow up of 6 months may be not sufficient enough for the assessment of negative EBUS-TBNA cases. Diagnostic EBUS-TBNA procedure was not followed up or underwent meadiastinoscopy for evaluating false-positive rate.

The important issue that has been highlighted through this study is the patients who were referred for lung cancer staging and higher negative predictive value, diagnostic accuracy obtained in cases performed under deep sedation/general anesthesia. Most of the lung cancer patients in our country present in advanced stage, thus inoperable.[13] An early referral to cancer center and prompt diagnosis is required to change this situation in developing countries. EBUS-TBNA in developing country is utilized mostly for granulomatous diseases rather than staging malignancy lung as highlighted in various studies.[7],[8]

A prospective study comparing conscious sedation versus deep/general anesthesia in determining diagnostic accuracy and negative predictive value of EBUS-TBNA can be planned based on the results of this retrospective study.

 CONCLUSION



Diagnosing extrathoracic malignancy metastasis and malignancy lung are major indications for the EBUS-TBNA procedure at our institute. The diagnostic accuracy overall was 91.8%. The negative predictive value, diagnostic accuracy, and sensitivity were higher for procedures performed under deep sedation/general anesthesia versus conscious sedation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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