Video-assisted Thoracic Surgery Lung Resection Research Articles

VATS Lung Resection in Bosnia and Herzegovina

Background: Video-assisted thoracic surgery (VATS) for both minor and major thoracic procedures has become routine practice worldwide. In this study, we present our experience with multiportal and uniportal VATS (MVATS and UVATS) in Bosnia and Herzegovina (B&H). MVATS and UVATS procedures were performed in two B&H Clinical Centers: Tuzla and Sarajevo. The first MVATS procedure at Tuzla Clinical Center was conducted in 2004, and the first UVATS lobectomy was performed in 2019. At Sarajevo Clinical Center, the initial MVATS took place in 2005, and the first UVATS lobectomy was carried out in 2020. Methods: We retrospectively analyzed 401 VATS procedures with prospective data, collected between 06/2017 and 04/2023. The VATS technique was employed for wedge resections, partial resections, lobectomies, and other types of resections, including metastasectomy. Results: Out of the 401 patients, 242 (60.34%) were male, and 159 (39.66%) were female, with a mean age of 57.2±23 years. The procedures consisted of 231 UVATS and 170 MVATS. Lobectomy was performed in 61 (15.21%) cases, wedge resections in 216 (51.37%), partial resections in 85 (21.19%), and other types of resections in 39 (9.72%) patients. The median duration of the procedure was 210 minutes for lobectomy, and 77.5 minutes for wedge and other types of resections. Major complications, such as bronchopleural fistula in 22 (5.49%) cases, wound infections in 20 (4.99%), atelectasis in 19 (4.74%), lung infiltrations in 15 (3.74%), and bleeding in 15 (3.74%) patients, were observed. The overall mean hospital stay for all procedures was 6.45 days. Conclusion: Uniportal and multiportal VATS techniques are feasible and safe for various indications in thoracic surgery. VATS can be performed in middle-income countries such as Bosnia and Herzegovina with acceptable results, by thoracic surgeons experienced in general thoracic surgery

Protocol for Development and Validation of Multivariable Prediction Models for Chronic Postsurgical Pain Following Video-Assisted Thoracic Surgery.

Chronic postsurgical pain (CPSP) is a common complication after thoracic surgery and associated with long-term adverse outcomes. This study aims to develop two prediction models for CPSP after video-assisted thoracic surgery (VATS). This single-center prospective cohort study will include a total of 500 adult patients undergoing VATS lung resection (n = 350 for development and n = 150 for external validation). Patients will be enrolled continuously at The First Affiliated Hospital of Soochow University in Suzhou, China. The cohort for external validation will be recruited in another time period. The outcome is CPSP, which is defined as pain with the numerical rating scale score of 1 or higher 3 months after VATS. Univariate and multivariable logistic regression analyses will be performed to develop two CPSP prediction models based on patients' data of postoperative day 1 and day 14, respectively. For internal validation, we will use the bootstrapping validation technique. For external validation, the discrimination capability of the models will be assessed using the area under the receiver operating characteristic curve, and the calibration will be evaluated using the calibration curve and Hosmer-Lemeshow goodness-of-fit statistic. The results will be presented in model formulas and nomograms. Based on the development and validation of the prediction models, our results contribute to early prediction and treatment of CPSP after VATS. Chinese Clinical Trial Register (ChiCTR2200066122).

Management of Complications During Video-Assisted Thoracic Surgery Lung Resection and Lymph Node Dissection.

Intraoperative events can occur during video-assisted thoracoscopic surgery (VATS) lobectomy due to unfavorable surgical anatomy, such as dense adhesions or calcifications around the pulmonary arteries. Troubleshooting intraoperative complications is essential for performing safe and successful VATS pulmonary resection and lymph node dissection. If continuous bleeding occurs or VATS does not proceed despite all measures, conversion to open thoracotomy should not be delayed.

Conversion from video-assisted thoracic surgery (VATS) to thoracotomy during major lung resection: how does it affect perioperative outcomes?

Since video-assisted thoracic surgery (VATS) was first performed in the early 1990s, there have been many developments, and the conversion rate has decreased over the years. This article highlights the specific outcomes of patients undergoing conversion to thoracotomy despite initially scheduled VATS lung resection. We retrospectively reviewed 501 patients who underwent thoracoscopic anatomic lung resection (i.e. lobectomy, segmentectomy or bilobectomy) between 1 January 2012 and 1 August 2017 at our institution. We explored the risk factors for surgical conversion and adverse events occurring in patients who underwent conversion to thoracotomy. A total of 44/501 patients underwent conversion during the procedure (global rate: 8.8%). The main reasons for conversion were (i) anatomical variation, adhesions or unexpected tumour extension (37%), followed by (ii) vascular causes (30%) and (iii) unexpected lymph node invasion (20%). The least common reason for conversion was technical failure (13%). We could not identify any specific risk factors for conversion. The global complication rate was significantly higher in converted patients (40.9%) than in complete VATS patients (16.8%) (P = 0.001). Postoperative atrial fibrillation was a major complication in converted patients (18.2%) [odds ratio (OR) 5.09, 95% confidence interval (CI) 1.80-13.27; P = 0.001]. Perioperative mortality was higher in the conversion group (6.8%) than in the VATS group (0.2%) (OR 33.3, 95% CI 3.4-328; P = 0.003). Through the years, the global conversion rate has dramatically decreased to <10%. Nevertheless, patients who undergo conversion represent a high-risk population in terms of complications (40.9% vs 16.8%) and perioperative mortality (6.8% vs 0.2%).

Risk factors associated with prolonged air leak after video-assisted thoracic surgery pulmonary resection: a predictive model and meta-analysis

This study aimed to establish a predictive model for prolonged air leak (PAL) after video-assisted thoracic surgery (VATS) lung resection; and additionally, to present a meta-analysis of the relevant literature to estimate the association between various clinical factors and PAL. A retrospective, case-control study was conducted using univariate analysis and logistic regression based on 493 medical records from patients who underwent VATS lung resection between January 2015 and August 2017 at our institution. PAL was defined as air leak more than 5 days after lung surgery. Subsequently, a nomogram was established as a predictive model. Relevant studies were screened from PubMed, Embase and Cochrane for relevant studies and data was extracted from those enrolled. Pooled odds ratios or weighted mean differences with corresponding 95% confidence intervals were calculated to estimate the association between various clinical factors and PAL. Incidence of PAL after VATS lung resection was observed in 54 (10.8%) of 493 patients. Logistic regression revealed that smoking (P=0.014), pulmonary function (P=0.011), pleural adhesion (P<0.001), stapling length (P<0.001), early postoperative drainage (P=0.002) were significantly associated with PAL. Our meta-analysis, including 17 eligible studies and 14 potential risk factors, further validating our findings. Upper lobectomy was determined to be a significant risk factor for PAL in Europeans and North Americans (OR =2.03, P<0.001), but not in Asians (OR =1.04, P=0.610). Importantly, the constructed nomogram demonstrated a good predictive ability (C-index =0.858). Lung stapling length and early postoperative drainage are important indicators for the evaluation of PAL occurrence. Upper pulmonary resection is a factor with particular regional differences as its association with PAL is not significant within Asian populations. Our nomogram, incorporating multiple factors, provided a simple and practical predictive model with value for clinical application.

Is adjuvant antifungal therapy after video-assisted thoracic surgery for pulmonary aspergilloma necessary?

The aim of this current retrospective study was to assess the necessity of postoperative antifungal therapy for pulmonary aspergilloma (PA) patients who underwent video-assisted thoracic surgery (VATS) lung resection. We enrolled 22 PA patients who underwent VATS lung resection between 2014 and 2018. Of these, 12 patients were prescribed antifungal agents during the perioperative period (group A), and the other 10 were treated with surgery alone without any antifungal therapy postoperatively (group B). All patients were immunocompetent. Seven patients (58.3%) developed postoperative complications in group A, including 2 cases of empyema (16.7%), 1 case of bronchopleural fistula (8.3%), 1 case of pneumonia (8.3%), 1 case of wound infection (8.3%), 1 case of bleeding (8.3%) and 1 case of atelectasis (8.3%). In group B, 3 patients (30%) developed postoperative complications, including 2 cases of pneumonia (20%) and 1 case of empyema (10%). There was no significant difference between the groups with respect to postoperative complications rates (P=0.23). The follow-up period ranged from 1 to 38 months (a median of 19 months), during which no hospital deaths, recurrence of disease or lesion relapses were noted in either group. Our results suggested that postoperative adjuvant antifungal therapy has limited advantages for the surgical treatment of PA in immunocompetent patients.

Video-assisted thoracic surgery for tiny pulmonary nodules with real-time image guidance in the hybrid theatre: the initial experience.

Localization of tiny lung nodules during video-assisted thoracic surgery (VATS) resection can be challenging. Real-time image-guided hookwire localization of the target lesions immediately followed by VATS lung resection in the hybrid operating theatre setting is an emerging approach. We retrospectively reviewed our experience with this form of hybrid operating theatre image-guided VATS (iVATS) for lung nodules 1.5 cm or less, or soft in consistency. These patients were compared with matched cohort who received standard hookwire localization in the radiology department. From February 2014 to September 2017, lung nodules of indeterminate nature in 32 consecutive patients with mean size 9.1±4.6 mm underwent iVATS. All were accurately localized by hookwire and successfully resected. There was no postoperative mortality. There were 21 (66%) malignant lesions, all with adequate resection margins. Major outcomes were compared with a comparable cohort of 8 patients who received standard hookwire localization and VATS (sVATS) performed at separate departments operation suites. sVATS groups has significantly longer 'at-risk' period for pneumothorax progression and hookwire dislodgement (109.5±57.1 minutes for sVATS vs. 41.1±15.0 minutes for iVATS, P=0.011), and a higher risk of hookwire dislodgement (25% for sVATS vs. 0 for iVATS, P=0.036). Real-time image-guided hookwire localization in the hybrid theatre setting is an effective facilitator of VATS resection of tiny lung nodules in selected patients, and may have added advantages in terms of safety and localization accuracy over the conventional sVATS method.

Advantages of wound retractor device versus rigid trocar at camera port in video-assisted thoracic surgery-a single institution experience.

rigid trocars are widely adopted in video-assisted thoracic surgery (VATS), despite some disadvantages: (I) cannula strong pressure on intercostal nerve stimulating postoperative pain; (II) limited movement of thoracoscopic devices on their fulcrum when extreme acute angles with the chest wall are needed. Wound retractor (WR) device, designed for laparoscopic surgery, it is also used in VATS, but to protect mini-thoracotomy. We compared the use of extra-small WR versus rigid trocar at camera port that is the most painful thoracostomy. The aim was to determine if WR is associated with less postoperative pain and better scope maneuverability. This is a single institution prospective study recorded and approved by ethics committee at our hospital. From October 2016 to June 2017, we enrolled 40 patients (statistical power 88%), randomized into two different groups. Group A (20 patients) underwent VATS lung resection using WR at camera port, group B (20 patients) using rigid trocar. Intra-operative data collected were maximum acute angle obtained between the camera and chest wall and chest wall thickness. Pain was measured by numerical analog scales (NAS) at 6, 12, 24, 48 and 72 hours after surgery. We also measured total morphine consumption at 72 h administered by patient controlled analgesia (PCA) system. No statistical significance was found in the demographic traits of the two groups (P=1). Statistically significant differences were found in favor of group A for both pain control, morphine consumption (P<0.001) and camera maneuverability (described as maximum acute angle obtained/chest wall thickness) (P<0.001). patients who had WR showed less postoperative pain. Moreover, WR presented other advantages: camera protection by small bleeding from chest wall, adaptability with every chest wall thickness, absence of skin injury around the port. We suggest its use instead of rigid trocar.

Single port VATS: recent developments in Asia.

Single port video-assisted thoracic surgery (VATS) is the most recent evolution in minimally invasive thoracic surgery. With increasing global popularity, the single port VATS approach has been adopted by experienced thoracic surgeons in many Asian countries. From initial experience of single port VATS lobectomy to the more complex sleeve resection procedures now forming part of daily practice in some Asia institutes, the region has been the proving ground for single port VATS approaches' feasibility and safety. In addition, certain technical refinements in single port VATS lung resection and lymph node dissection have also sprung from Asia. Novel equipment designed to facilitate single port VATS allowing further reduce access trauma are being realized by the partnership between surgeons and the industries. Advanced thoracoscopes and staplers that are narrower and more maneuverable are particularly important in the smaller habitus of patients from Asia. These and similar new generation equipment are being applied to single port VATS in novel ways. As dedicated thoracic surgeons in the region continue to striving for excellence, innovative ideas in single incision access including subxiphoid and embryonic natural-orifice transluminal endoscopic surgery (e-NOTES) have been explored. Adjunct techniques and technology used in association with single port VATS such as non-intubated surgery, hybrid operating room image guidance and electromagnetic navigational bronchoscopy are all in rapid development in Asia.

Reduce chest pain using modified silicone fluted drain tube for chest drainage after video-assisted thoracic surgery (VATS) lung resection.

The aim of this study was to assess the feasibility, efficacy and safety of a modified silicone fluted drain tube after video-assisted thoracic surgery (VATS) lung resection. The prospective randomized study included 50 patients who underwent VATS lung resection between March 2015 and June 2015. Eligible patients were randomized into two groups: experimental group (using the silicone fluted drain tubes for chest drainage) and control group (using standard drain tubes for chest drainage). The volume and characteristics of drainage, postoperative (PO) pain scores and hospital stay were recorded. All patients received standard care during hospital admission. In accordance with the exit criteria, three patients were excluded from study. The remaining 47 patients included in the final analysis were divided into two groups: experiment group (N=24) and control group (N=23). There was no significant difference between the two groups in terms of age, sex, height, weight, clinical diagnosis and type of surgical procedure. There was a trend toward less PO pain in experimental group on postoperative day (POD) 1, with a statistically significant difference. Patients in experimental group had a reduced occurrence of fever [temperature (T) >37.4 °C] compared to the control group. The silicone fluted drain tube is feasible and safe and may relieve patient PO pain and reduce occurrence of fever without the added risk of PO complications.

Editorial comment on: "Major morbidity after video-assisted thoracic surgery lung resections: a comparison between the European Society of Thoracic Surgeons definition and the Thoracic Morbidity and Mortality system" by Sandri A, et al.

The current issue of the Journal of Thoracic Disease publishes the remarkable work of Sandri and associates (1) which not only contributes to a deeper understanding of the distribution of postoperative complications, but also questions the traditional classification of major complications, in the framework of video-assisted thoracic surgery (VATS) lung resection.

Major morbidity after video-assisted thoracic surgery lung resections: a comparison between the European Society of Thoracic Surgeons definition and the Thoracic Morbidity and Mortality system.

The thoracic morbidity and mortality (TM&M) classification system univocally encodes the postoperative adverse events by their management complexity. This study aims to compare the distribution of the severity of complications according to the TM&M system versus the distribution according to the classification proposed by European Society of Thoracic Surgeons (ESTS) Database in a population of patients submitted to video assisted thoracoscopic surgery (VATS) lung resection. A total of 227 consecutive patients submitted to VATS lobectomy for lung cancer were analyzed. Any complication developed postoperatively was graded from I to V according to the TM&M system, reflecting the increasing severity of its management. We verified the distribution of the different grades of complications and analyzed their frequency among those defined as "major cardiopulmonary complications" by the ESTS Database. Following the ESTS definitions, 20 were the major cardiopulmonary complications [atrial fibrillation (AF): 10, 50%; adult respiratory distress syndrome (ARDS): 1, 5%; pulmonary embolism: 2, 10%; mechanical ventilation >24 h: 1, 5%; pneumonia: 3, 15%; myocardial infarct: 1, 5%; atelectasis requiring bronchoscopy: 2, 10%] of which 9 (45%) were reclassified as minor complications (grade II) by the TM&M classification system. According to the TM&M system, 10/34 (29.4%) of all complications were considered minor (grade I or II) while 21/34 (71.4%) as major (IIIa: 8, 23.5%; IIIb: 4, 11.7%; IVa: 8, 23.5%; IVb: 1, 2.9%; V: 3, 8.8%). Other 14 surgical complications occurred and were classified as major complications according to the TM&M system. The distribution of postoperative complications differs between the two classification systems. The TM&M grading system questions the traditional classification of major complications following VATS lung resection and may be used as an additional endpoint for outcome analyses.

Index of prolonged air leak score validation in case of video-assisted thoracoscopic surgery anatomical lung resection: results of a nationwide study based on the French national thoracic database, EPITHOR.

The incidence rate of prolonged air leak (PAL) after lobectomy, defined as any air leak prolonged beyond 7 days, can be estimated to be in between 6 and 15%. In 2011, the Epithor group elaborated an accurate predictive score for PAL after open lung resections, so-called IPAL (index of prolonged air leak), from a nation-based surgical cohort constituted between 2004 and 2008. Since 2008, video-assisted thoracic surgery (VATS) has become popular in France among the thoracic surgical community, reaching almost 14% of lobectomies performed with this method in 2012. This minimally invasive approach was reported as a means to reduce the duration of chest tube drainage. The aim of our study was thus to validate the IPAL scoring system in patients having received VATS anatomical lung resections. We collected all anatomical VATS lung resections (lobectomy and segmentectomy) registered in the French national general thoracic surgery database (EPITHOR) between 2009 and 2012. The area under the receiver operating characteristic (ROC) curve estimated the discriminating value of the IPAL score. The slope value described the relation between the predicted and observed incidences of PALs. The Hosmer-Lemeshow test was also used to estimate the quality of adequacy between predicted and observed values. A total of 1233 patients were included: 1037 (84%) lobectomies and 196 (16%) segmentectomies. In 1099 cases (89.1%), the resection was performed for a malignant disease. Ninety-six patients (7.7%) presented with a PAL. The IPAL score provided a satisfactory predictive value with an area under the ROC curve of 0.72 (0.67-0.77). The value of the slope, 1.25 (0.9-1.58), and the Hosmer-Lemeshow test (χ(2) = 11, P = 0.35) showed that predicted and observed values were adequate. The IPAL score is valid for the estimation of the predictive risk of PAL after VATS lung resections. It may thus a priori be used to characterize any surgical population submitted to potential preventive measures.

Early Outcomes Following Uniportal Video-Assisted Thoracic Surgery Lung Resection

SESSION TITLE: Thoracic Surgery Posters

Video-assisted thoracic surgery for lung cancer in hemodialysis patients

In recent years, the number of hemodialysis patients has been continuously increasing. At the same time, the use of video-assisted thoracic surgery (VATS) for lung cancer has also increased. However, reports of the outcome of VATS in hemodialysis patients are still quite rare. From 1995 to 2011, 14 patients with non-small cell lung cancer who were also receiving hemodialysis underwent lung resection by open thoracotomy or VATS at our institution. These patients were divided into two groups as follows: open (five men and four women, mean age: 68.7 years) and (2) VATS (three men and two women, mean age: 64.0 years). We compared the clinical outcomes of these two groups. Lobectomy was performed in eight patients in the open group, including one patient who also underwent a pneumonectomy, and in four patients in the VATS group, including one who also underwent a wedge resection. There were no significant difference between the groups' operation times, intraoperative blood loss, length of postoperative chest drainage, and length of postoperative hospitalization. There were no hospital deaths in either group. The 5-year survival rate was 42.9% in the open group and 37.5% in the VATS group. This difference was not significant (P=0.73). VATS lung resection for lung cancer patients on hemodialysis is considered an acceptable treatment modality, though the long-term survival rate of such patients is relatively low, which can be attributed to the diseases underlying the need for hemodialysis.

Video-Assisted Thoracic Surgery Pulmonary Resection for Lung Cancer in Patients with Poor Lung Function

The aim of this study is to evaluate the early outcome of patients with poor lung function who underwent video-assisted thoracic surgery (VATS) pulmonary resection for primary non-small cell lung carcinoma. We reviewed retrospectively the records of patients with lung cancer undergoing VATS lung resection over a period of 5 years. Twenty-five patients with preoperative poor lung function defined as forced expiratory volume in 1 second less than 0.8 L or the percentage predicted value for forced expiratory volume in 1 second less than 50% were identified. Thirteen patients underwent VATS lobectomies and 12 VATS wedge resections. Data were analyzed with respect to demographics, risk factors, and early postoperative outcome and survival. There were 8 cases of morbidities (29%) and no surgical mortality. Five of these 8 patients had respiratory-related complications after surgery. A deterioration in pulmonary performance as indicated by the Eastern Cooperative Oncology Group (ECOG) score was seen in 7 patients (28%), with only 1 patient having an ECOG score greater than 2. No patient required home oxygen supplementation beyond the third month postoperatively. After a median follow-up period of 15.1 months (range, 1 to 24), 5 patients died. Only 1 patient (4%) died of a respiratory complication (pneumonia 6 weeks after surgery). The other 4 deaths were due to recurrent or metastatic disease. The actuarial survival rates at 1 and 2 years were 80% and 69%, respectively. Video-assisted thoracic surgery pulmonary resection for cancer in patients with poor lung function can achieve acceptable functional and oncologic outcome.

Video-assisted thoracic surgery lung resection after endobronchial valve placement

1 Endobronchial valve (EBV) placement has emerged as an alternative approach for treating patients with severe emphysema. The improvements in lung function after EBV placement, which allows video-assisted thoracic surgery (VATS) lung resection in a previously nonsurgical candidate, have not been reported. We present a case of VATS lung resection after EBV placement in a patient with severe emphysema to illustrate clinical and surgical aspects in this new category of patients.

Video-assisted thoracoscopic surgery for pulmonary nodules: rationale for preoperative computed tomography-guided hookwire localization.

Video-assisted thoracic surgery (VATS) provides a minimally invasive means to resect pulmonary nodules (PN). Deep localization of PN may jeopardize VATS lung resection. The aim of this study was to establish the utility of preoperative computed tomography (CT)-guided hookwire localization of PN. Between January 1993 and September 2001, we performed 151 VATS resections for PN. Preoperative CT-guided hookwire localization was not performed in 98 patients (group I); it was done just before surgery in 53 patients (group II) when, at CT scan, the distance of PN from the lung surface was >15 and/or when the size was <10 mm. Pneumothorax occurred in four patients (7.5%). Hookwire dislodged in four patients, but the hematoma left on the visceral pleura made thoracoscopic localization possible in three of these. Seventeen patients (17%) in group I and 4 (7.5%) in group II required conversion to thoracotomy (P< or =0.05). The most common reason for conversion was impossibility to localize PN in group I (nine cases) and deep localization requiring local enucleation in group II (two cases). In 31 group II patients (58%) hookwire positioning led to successful VATS resection that would otherwise have been impossible because PN were neither visible nor palpable. Preoperative CT-guided hookwire localization for pulmonary nodules is an effective technique which allows VATS resection of PN <10 mm located >15 mm from the pleural surface. Even when PN are subpleural but <10 mm, hookwire localization makes VATS resection faster. Apical and diaphragmatic localization of PN are limitations to the procedure.

VATS is an adequate oncological operation for stage I non-small cell lung cancer.

This study was designed to determine the long-term prognosis of video-assisted thoracic surgery (VATS) vs. open lung resections for patients with pathological stage I non-small cell lung cancer (NSCLC). The medical records of all patients who underwent lung resection for a pathological stage I NSCLC were reviewed for the period from 1990 to 1999, by screening of a database into which data were entered prospectively. There were 511 patients (430 males and 81 females) whose age averaged 63+/-10 years who underwent 515 lung resections. Our VATS experience began in 1993 with selected stage I patients, and since that date an average of one patient on four was managed with VATS. Lung resections consisted of 25 wedge resections or segmentectomies (seven VATS), 390 lobectomies (92 VATS), 19 bilobectomies (one VATS) and 81 pneumonectomies (ten VATS). Lymph node dissection was performed in all cases. There were significantly more females (P=0.01) and adenocarcinoma (P=0.02) in the VATS group (n=110) when compared to the open group (n=405). Tumour size averaged 4+/-2 cm in the open group and 3+/-2 cm in the VATS group (P=0.04). The distribution of T1/T2 tumours was 97/308 and 50/60, respectively (P=0.0001). At follow-up, cancer recurrence could be documented in 117 patients, with no difference of incidence between the two groups (22.5 vs. 24.5%; P=0.64). Estimated Kaplan-Meier 5-year survival rates, including the operative mortality as well as any cancer-related and unrelated death, were 62.8% (confidence interval (CI): 56.8-68.7%) vs. 62.9% (CI: 51.4-74.4%), respectively (P=0.60). The advent of VATS did not influence the patients' survival: 5-year survival rate was 63.9% (CI: 55.3-72.5%) for the period from 1990 to 1992, and 58.8% (CI: 51.7-65.9%) for the period from 1993 to 1999 (P=0.65). Subgroups survival analysis according to the T status did not show any statistically significant difference between the two groups. VATS lung resection with lymph node dissection achieved a 5-year survival similar to that achieved by the conventional approach. VATS is a valuable option for the management of selected patients with an early-stage NSCLC.