Transthoracic imaging-guided needle biopsy: 5 years' experience in Indonesia.

Introduction
Transthoracic needle biopsy (TNB) is a widely used routine biopsy procedure, particularly for lung and mediastinal consolidations. This procedure is almost always performed using imaging guidance, such as computed tomography (CT) and ultrasound (US), and overall demonstrates superior tissue diagnostic yield compared to transthoracic needle aspiration. The choice of modality depends on facility availability, operator preference, cost and the patient’s condition [1]. The reported accuracy and complication rates vary greatly. Sano et al. (2023) stated that the accuracy of TNB depends on nodule size, needle size, number of punctures, the imaging guidance, and the availability of rapid cytological evaluation [2]. Moreover, the risk of complications depends on the depth of needle puncture, needle size, lesion size and needle passage through the lung parenchyma [2,3]. To our knowledge, no study has been conducted to explore the accuracy and complication rates of percutaneous transthoracic needle biopsy in a large population in our region. Identifying the risk factors associated with these outcomes may improve clinical judgment and management strategies. The present study aimed to report five years of experience in the National Respiratory Referral Hospital in Jakarta, Indonesia.

Methods

Study design and patients
A retrospective study was performed from January 2020 to December 2024. All data were collected from two units (the CT scan room and the respiratory procedure room), where TNB procedures were routinely performed. In this study, the CT-guided TNB was performed by pulmonologists. Some TNB procedures were also performed in the wards, but since the data were not recorded systematically, we could not yet extract the data from the electronic medical records. After all the data had been collected, data filtering was done for publication.
We included patients aged 18 years or older who were diagnosed with either lung or mediastinal consolidations and underwent percutaneous transthoracic needle biopsy. We excluded patients who underwent TNB procedures performed blindly without real-time imaging guidance. Throughout the five years, we used almost the same core needle biopsy type, thereby minimizing the risk of bias. The study received approval from Persahabatan Hospital Ethics Committee (Ethic No: 0066/KEPK-RSUPP/04/2025).

Transthoracic needle biopsy
Transthoracic needle biopsy is a percutaneous core needle puncture through the thoracic wall to obtain samples from the lung or mediastinal zone. A cutting core biopsy of 14 or 16 gauge was used with multiple insertions. Large filament specimens were obtained and examined for pathology. Complications were assessed immediately after the procedure by clinical complaints and CT evaluation. Patients were observed for 1 hour after the procedure in the procedure room. If there was any deterioration, a follow-up chest X-ray was performed to confirm any abnormalities. Fatal outcomes were evaluated within 24 hours after the procedure. Eight pulmonologists performed TNB procedures in both units, all of whom had the same qualifications.

Statistical analysis
IBM SPSS software version 30.0 for Mac OS was used for analyzing the data. Qualitative data were presented as numbers and percentages, while quantitative data were presented as mean, median, standard deviation (SD) and interquartile range (based on the normality of the data). Both parametric and non-parametric analyses were used for significance testing. A p-value <0.005 was considered significant.

Results
One thousand seven hundred and sixteen patients were recorded in the database. We ruled out 23 pediatric patients, 17 duplicate entries, and 85 patients who underwent only transthoracic needle aspiration (Figure 1). For the final analysis, 1,591 patients were included in the study. In detail, we performed 187 procedures in 2020, 221 procedures in 2021, 360 procedures in 2022, 402 procedures in 2023, and 421 procedures in 2024. The number of TNB procedures was the lowest in 2020, coinciding with the COVID-19 pandemic. During this period, patients demonstrated a reduced tendency to seek medical care or undergo diagnostic procedures. In addition, CT usage was prioritized for COVID-19 services; therefore, TNB procedures were generally performed under US guidance.
The participants were predominantly male (65.4%), with a median age of 55 years. Right lung consolidation was the most prevalent (46.9%) as the TNB target, followed by the left lung (32.6%), and the mediastinum (20.5%). The majority of procedures were performed under CT guidance (89.9%) and involved a 16-gauge core needle biopsy (99.6%). The median needle path length was 3.9 cm. The overall accuracy of the TNB procedure was 96.3% with adenocarcinoma as the most frequent pathology result (34.1%). The sensitivity was 95.7% and the specificity was about 99.6%. Table 1 provides an overview of the participants’ characteristics.
The non-small cell lung cancer type (including adenocarcinoma and squamous cell carcinoma) remained the majority of lung cancer pathology findings (49.8%). Lymphoma was the most common type of mediastinal mass. Its proportion was similar to the number of granulomatous inflammations that are suggestive of TB. Other histopathology findings in this study were mediastinal germ cell tumor, yolk sac tumor, sarcoma, mesenchymal tumor, teratoma, plasmacytoma, adenoid cystic carcinoma, fibrous dysplasia, extramedullary hematopoiesis, metastatic of thyroid carcinoma, multiple myeloma, and soft tissue tumor. Table 2 shows the pathology results of TNB procedures, with Tables 3 and 4 for further details regarding the other findings found and the final diagnosis for inconclusive results.
The majority of TNB procedures (98.4%) were performed safely and without complications. The proportion of complications was significantly correlated with the presence of granulomatous inflammation and the use of a larger needle. There were 16 patients (1.0%) who experienced immediate pneumothorax and 25% of them required chest tube placement. In the group of patients with pneumothorax, 31.3% had tuberculosis (TB), and 18.8% of them had undergone biopsy using a 14-gauge needle. Nine patients reported hemoptysis after the procedure. After administering hemostatic agents, the bleeding resolved spontaneously and did not require hospitalization. Most of these patients (66.7%) had TB. Only six patients underwent biopsy using a 14-gauge needle, and most of them (66.7%) developed complications. No fatal complications, such as respiratory failure or mortality, were observed within 24 hours post-procedure. Further details regarding complications are available in Table 1.

Discussion
Transthoracic needle biopsy is widely utilized as a simple, accurate and cost-effective diagnostic procedure for various thoracic diseases. To the best of our knowledge, this is the first large-scale study of its kind conducted in our region. We reported a total of 1,591 adult patients who underwent TNB for diagnostic purposes, either for lung biopsy (1,265 patients) or mediastinal biopsy (326 patients). Computed tomography was predominantly used to guide the procedure (89.9%), rather than US. In our study, US-guided TNB demonstrated a higher positivity rate than CT-guided TNB (97.5% vs. 78.7%). This result contrasts with previous studies, which reported a higher accuracy of CT-guided TNB compared to US-guided TNB (96.1% vs. 88.7%) [4,5]. This discrepancy may be attributed to the larger median lesion size (median 52 mm vs. 46 mm) and smaller total number of patients in the US group. Larger lesions make it easier for the operator to perform the procedure and to select the target site based on density. Although larger lesions (>10–15mm) are associated with better diagnostic accuracy, lesions greater than 50 mm in diameter may result in a lower diagnostic yield [6].
As a standard operating procedure in our hospital, TNB was routinely performed under CT guidance. However, for patients unable to lie down or at risk of respiratory failure, the procedure was carried out under US guidance in the sitting position. Only lesions adjacent to the chest wall could be visualized by the US. The majority of US-guided TNBs in this study were performed in patients with superior vena cava syndrome or central airway obstruction. Another contributing factor was the shorter needle path length (median 28 mm vs. 39mm). Ohno et al. (2012) concluded that a needle path length of 40 mm or less was significantly related to higher diagnostic accuracy [7]. Computed tomography was the preferred imaging guidance modality for diagnostic TNB procedures in our institution. We acknowledge that other modalities exist that may improve diagnostic yield and reduce complications, such as fluoroscopy and cone-beam CT guidance; however, these are not yet available at our institution [8].
Adenocarcinoma was the most frequent pathology result of TNB (37.7%) in lung biopsy, and lymphoma (8.8%) in mediastinal biopsy. In all procedures, pathology revealed that 56.6% were carcinomas, 12.9% were mediastinal lymphoma and thymoma, 8.3% were chronic granulomatous inflammations suggestive of TB, and 2.6% were other findings. The predominant finding of carcinoma was similar to the results of Yang et al. (2015), who reported 72.3% carcinoma in CT-guided TNB for solitary pulmonary nodules [9]. Mediastinal lymphoma and thymoma were the most common results in our study, likely due to their predominance in the anterior mediastinum, which is accessible by core needle puncture. Our results also showed that TNB is a reliable diagnostic procedure for TB. It was also stated in the previous study that concluded good efficiency and safety of CT-guided core needle biopsy for pulmonary TB diagnosis [10].
The overall accuracy of the TNB procedure in treating lung and mediastinal consolidation was 96.3%, with a sensitivity of 95.7% and a specificity of 99.6%. A study by Cesar et al. (2019), conducting CT-guided transthoracic core-needle biopsies of mediastinal and lung lesions, also showed a similar overall accuracy of 91.1% [11]. Other studies also report similar results, with sensitivity above 90%, especially for malignant cases [2,9]. The positivity rate for mediastinal lesions in this study was lower than for lung lesions (88.0% vs. 97.2%). A multicenter study in 2019 reported that diagnostic failure was associated with a final diagnosis of mediastinal lymphoma (adjusted odds ratio 10.66) [12].
There were 25 complication cases (1.6%) and zero fatal complications within 24 hours after procedures. The complication consisted of 16 cases of pneumothorax and 9 cases of hemoptysis. The rate of complications in this study was lower than in previous studies, which had reported rates ranging from 3.8% to 38.8% [2,4,9,11,13]. This difference was thought to be caused by the majority of lesions in this study being adjacent to the chest wall. In our setting, if the lesions did not attach to the chest wall or were central lesions, we prioritized performing bronchoscopy as a first-line diagnostic approach. This could reduce the risk of complications, especially pneumothorax, by minimizing the unnecessary passage of the needle through the lung tissue. Further detail regarding factors associated with complications following TNB are provided in Table 5. However, the total cost of transbronchial lung biopsy (TBLB) is higher than TNB. For comparison, in our institution, the cost of TBLB ranges from $1,800 to $3,725 USD, while the cost of TNB is $100 to $1,550 USD.
In our analysis, TNB complications were significantly correlated with TB lesions and a larger needle. Of the total of 25 complications, 5 patients with pneumothorax and 6 patients with hemoptysis had TB. It was thought that our puncture of the target lesion might have breached the cyst structure in bronchioles that were surrounded by pulmonary tuberculoma or infiltrated the layer separating the vessel and bronchial lumen, resulting in bronchial bleeding [14,15]. Chen et al. (2018) also reported the incidences of complications of CT-guided TNB, such as pneumothorax and bleeding, were 9.3% and 19.4% [10]. Regarding the size and type of biopsy needle, our institution had set it according to availability and national insurance coverage. Almost all procedures (99.6%) used a 16-gauge needle, which was relatively larger than the commonly used sizes, which range from 18 to 22 gauge [16]. As our institution is a national respiratory referral hospital, it was necessary to take a larger sample to obtain more accurate results. It was also preferred when there were necrotic lesions or a definite diagnosis was needed. There were only 6 patients who used a 14-gauge needle in early 2020. For this group, 4 of them developed a complication. Based on this experience, this size was discontinued. This result differed from a previous study by Ocak et al. (2016), which reported that core-needle biopsy with a 14-gauge needle resulted in fewer major bleeding complications compared with fine-needle biopsy using a 22-gauge needle [17].
The strength of this study lies in its presentation of the diagnostic profile and safety of the TNB procedure in a large population, particularly in our nation. Our findings highlight a high diagnostic yield and a significant risk of TNB, making it a reliable first-line diagnostic procedure for peripheral pulmonary and mediastinal consolidation, with lower costs. This study also demonstrated that TNB can be effectively applied in primary health services using US guidance, which can increase the scope of diagnostic levels nationwide. The limitations of this study were incomplete database records and a lack of cost-effectiveness assessment. Thus, we could not reflect the real total populations and diagnostic burden. This study also did not include rapid on-site evaluation (ROSE) as a combination diagnostic strategy. This study also did not include microbiological testing of 14 patients who were suspected of having TB. However, further research is recommended to conduct a prospective study with a multicenter approach to obtain the overall yield and safety profile nationwide [12]. In addition, it is essential to evaluate TNB with fine-needle aspiration biopsy and include other confounding factors that may influence the outcome and aid in assessing patient selection [18,19].

Conclusion
Transthoracic needle biopsy is a reliable diagnostic procedure with high accuracy and a favorable safety profile. This study demonstrated that TNB is effective for diagnosing both peripheral pulmonary and mediastinal lesions. While CT guidance remained the standard approach in our institution, US-guided TNB also showed good performance, particularly in patients with limited positioning tolerance or airway compromise. Complications were infrequent and mostly associated with TB lesions and the use of larger biopsy needles. These findings support the use of TNB as a first-line diagnostic option that is safe, efficient, and adaptable to various clinical settings, including resource-limited and primary healthcare services.