Lobulated tumor contour as a predictor of preoperative tumor invasion of the lung or pericardium in thymoma patients.

PURPOSE: Preoperative investigations to detect invasion to neighboring organs are important for deciding on the most appropriate surgical approach for thymoma. We evaluated preoperative computed tomography (CT) findings in thymoma patients to identify the CT features associated with tumor invasion. METHODS: Clinicopathologic information on 193 patients who underwent surgical resection for thymoma at Chiba University Hospital between 2002 and 2016 was collected retrospectively. The surgical pathology identified invasion of thymoma in 35 patients: in the lung (n = 18), pericardium (n = 11), or both (n = 6). Contact lengths between the tumor contour and lung (CLTL) or pericardium (CLTP) were measured at the maximum section of the tumor on axial CT. Univariate and multivariate analyses were performed to analyze the relationship between pathological invasion of the lung or pericardium and the clinicopathologic features. RESULTS: The mean CLTL and CLTP were significantly longer in patients with invasion of the neighboring organs than in those without invasion. A lobulated tumor contour was identified in 95.6% of the patients with invasion of the neighboring organs. A multivariate analysis revealed that a lobulated tumor contour was significantly associated with both lung and pericardial invasion. CONCLUSIONS: A lobulated tumor contour was significantly associated with lung and/or pericardial invasion in thymoma patients.

A simple nomogram for predicting occult lymph node metastasis of non-small cell lung cancer from preoperative computed tomography findings, including the volume-doubling time.

PURPOSE: Latent lymph node metastasis is a clinical concern in the surgical treatment of non-small cell lung cancer (NSCLC). The present study identified a simple tool, including the volume-doubling time (VDT), for evaluating the risk of nodal metastasis. METHODS: We reviewed, retrospectively, 560 patients who underwent radical resection for cN0M0 NSCLC. The whole tumor VDT and solid component VDT (SVDT) for differentiating the histological type and adenocarcinoma subtype were analyzed and a nomogram was constructed using variables selected through a stepwise selection method. The model was assessed through a calibration curve and decision curve analysis (DCA). RESULTS: Lymph node metastases were detected in 89 patients (15.9%). The SVDT tended to be longer in patients with adenocarcinoma (294.5 days, p < 0.0001) than in those with other histological types of NSCLC, but was shorter when the solid/micropapillary component was predominant (127.0 days, p < 0.0001). The selected variables (tumor location, solid component diameter, consolidation tumor ratio, SVDT, and carcinoembryonic antigen) demonstrated significant differences and were used for the nomogram. The calibration curve indicated consistency, and the DCA showed validity across most threshold ranges from 0 to 68%. CONCLUSIONS: The established nomogram is a useful tool for the preoperative prediction of lymph node metastasis, and the SVDT was the most influential factor in the nomogram.

Surgical treatment for chronic pulmonary coccidioidomycosis: a retrospective study from a single institution.

PURPOSE: Coccidioidomycosis, caused by the Coccidioides species, is a well-known disease in the Southwestern United States and North Mexico, with scattered reports in Latin America countries. While this disease is still rare in Japan and other Asian countries, its incidence has been increasing over the last two decades. Coccidioides species are highly infectious and require caution when encountered. This study presents a case series of chronic pulmonary coccidioidomycosis surgically treated at a single institution. METHODS: We conducted a retrospective chart review of six patients who underwent lung resection for pulmonary coccidioidomycosis at Chiba University Hospital between January 2007 and December 2021. RESULTS: All six patients had travelled to the Southwestern United States. Preoperative serology was negative for the anti-Coccidioides antibody in four patients and positive in two. Chest computed tomography revealed a single, well-defined round nodule in all patients. Preoperative biopsy taken from three patients failed to obtain a definitive diagnosis. Histopathological examination of the resected pulmonary nodules revealed granulomas that contained numerous spherules with many endospores, thereby confirming the diagnosis of pulmonary coccidioidomycosis. CONCLUSIONS: Pulmonary coccidioidomycosis should be suspected based on travel history and radiological findings. Meticulous care should be taken during specimen processing to prevent cross infection.

Association of frequent hypermethylation with high grade histological subtype in lung adenocarcinoma.

Lung adenocarcinoma is classified morphologically into five histological subtypes according to the WHO classification. While each histological subtype correlates with a distinct prognosis, the molecular basis has not been fully elucidated. Here we conducted DNA methylation analysis of 30 lung adenocarcinoma cases annotated with the predominant histological subtypes and three normal lung cases using the Infinium BeadChip. Unsupervised hierarchical clustering analysis revealed three subgroups with different methylation levels: high-, intermediate-, and low-methylation epigenotypes (HME, IME, and LME). Micropapillary pattern (MPP)-predominant cases and those with MPP components were significantly enriched in HME (p = 0.02 and p = 0.03, respectively). HME cases showed a significantly poor prognosis for recurrence-free survival (p < 0.001) and overall survival (p = 0.006). We identified 365 HME marker genes specifically hypermethylated in HME cases with enrichment of "cell morphogenesis" related genes; 305 IME marker genes hypermethylated in HME and IME, but not in LME, with enrichment "embryonic organ morphogenesis"-related genes; 257 Common marker genes hypermethylated commonly in all cancer cases, with enrichment of "regionalization"-related genes. We extracted surrogate markers for each epigenotype and designed pyrosequencing primers for five HME markers (TCERG1L, CXCL12, FAM181B, HOXA11, GAD2), three IME markers (TBX18, ZNF154, NWD2) and three Common markers (SCT, GJD2, BARHL2). DNA methylation profiling using Infinium data was validated by pyrosequencing, and HME cases defined by pyrosequencing results also showed the worse recurrence-free survival. In conclusion, lung adenocarcinomas are stratified into subtypes with distinct DNA methylation levels, and the high-methylation subtype correlated with MPP-predominant cases and those with MPP components and showed a poor prognosis.

[Robot-assisted Thoracic Surgery for Mediastinal Tumor].

In Japan, robot-assisted thoracic surgery (RATS) was introduced in thoracic surgery in 2001, but it did not become widespread. However, surgery for mediastinal tumors and lobectomy for lung cancer with RATS were covered by insurance in 2018 and are currently becoming popular as a general practice, following video-assisted thoracic surgery(VATS). Forty-six patients with mediastinal tumors were treated by RATS from February 2014 to November 2022 in our institution. Theoretically, the RATS approach is performed from one side in a semi-supine position under CO2 insufflation as with the VATS approach of our institution. In the case of extended thymectomy, a bilateral approach is performed by changing the patient's position. The median surgery time was 88 min, and the median surgery time in unilateral and bilateral approaches were 79 and 208 min, respectively. Blood loss during surgery was quite minimum, and no patients required conversion to VATS or thoracotomy. Regarding adverse events, postoperative bleeding was observed in one patient (2.2%). RATS has been successfully introduced and expanded safely for mediastinal tumors. Considering further expansion of RATS indications while conducting verification by comparison with VATS in the future is necessary.

[The Basic Research of Antigen-antibody Reaction in Lung Transplantation].

Lung transplantation has become popular in Japan, showing better survival rate than other countries. However, the results are still not satisfactory compared with other solid organ transplantation. One of the reasons for this might be that knowledge on donor-specific antibodies or antibody-related rejection, which has been attracting attention these days, is less than that of kidney or liver transplantation. Our laboratory has continued basic research in this field using rodent lung transplantation model. We have previously shown that type V collagen is associated in chronic rejection as an autoimmune, and that oral administration of type V collagen induces tolerance. The murine chronic rejection model of the minor antigen mismatch was developed, and involvement of the humoral immunity and role of the complement activation were shown. We are now studying the effects of immune checkpoint molecules, which play a central role in the field of cancer therapy, on rejection after lung transplantation. We are also working to verify the effects of anti-complement drugs and molecular targeted drugs in the future treatment on rejection.

Endobronchial ultrasound-guided transbronchial needle aspiration in patients with previously treated lung cancer.

PURPOSE: The sampling and accurate diagnosis of lymph nodes during the clinical history of lung cancer are essential for selecting the appropriate treatment strategies. This study aims to evaluate the feasibility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in patients with previously treated lung cancer. METHODS: Patients who underwent EBUS-TBNA after treatment for lung cancer were retrospectively reviewed. We classified the patients into two groups; Group 1 (G1): Indicated to have a recurrence of new lesions after radical surgery or chemo/radiotherapy with a curative intent; and Group 2 (G2): Indicated to have residual tumor cells after undergoing primary treatment for chemo/radiotherapy or re-staging after induction therapy prior to surgery. RESULTS: Seventy previously treated lung cancer cases (G1, n = 52; G2, n = 18) were enrolled. Thirty-two cases (61.5%) had recurrent disease in G1, and 9 cases (50.0%) had nodal metastasis in G2. The diagnostic accuracy was 95.2% in G1 and 88.9% in G2. Twenty-four cases were examined for epidermal growth factor receptor (EGFR) mutations, and 9 (37.5%) cases had mutations, including two cases with a T790M mutation. Furthermore, in one case, a re-biopsy revealed that the initial adenocarcinoma had transformed into small cell lung cancer. CONCLUSION: Performing EBUS-TBNA during lung cancer treatment showed a high diagnostic yield. Samples obtained by EBUS-TBNA were helpful in determining when to perform repeat biomarker testing as well as for making pathological re-evaluations.

Lung cancer staging: State of the art in the era of ablative therapies and surgical segmentectomy.

Implementation of lung cancer screening and improvements in imaging are expected to increase the proportion of lung cancer diagnosed at an early stage. The standard of care has historically been anatomic lobectomy; however, there is now an array of surgical and non-surgical approaches for management of local disease either in active use or under investigation. By their nature, these new modalities offer a theoretical trade-off of reduced morbidity in exchange for reduced efficacy in the setting of advanced disease. It is therefore critical that patients being considered for these approaches (e.g. surgical segmentectomy and SABR) be accurately staged to maximize the potential for definitive treatment. In this article, we will review current approaches to the staging of patients being considered for segmentectomy or ablation. This will serve as a foundation to highlight important questions deserving further investigation.

Rabbit VX2 lung tumor models can form early nodal metastases.

BACKGROUND: The rabbit squamous cell cancer line, VX2, has been used to generate various tumor models in rabbits. It is notable for its ability to generate nodal metastases. However, the timing and extent of nodal metastases vary by primary inoculation site and methodology. The development of metastases specifically in lung cancer models has not been well-described. We sought to characterize the generation of nodal metastases in rabbit transbronchial VX2 lung tumor models. METHODS: Rabbit VX2 lung tumor models were created in the right lung via transbronchial injection and serially imaged by computed tomography. Rabbits (n = 15) were sacrificed from between 5 and 24 days post-inoculation for collection of the ipsilateral and contralateral paratracheal lymph nodes. These underwent histopathological evaluation for metastases using hematoxylin and eosin as well as cytokeratin AE1/AE3 immunohistochemical staining. RESULTS: Nodal metastases were detectable as early as 1 week after inoculation but were more prevalent with longer inoculation; all rabbits at > 2 weeks post-inoculation had nodal metastases. Contralateral metastases were in general seen later than ipsilateral metastases. Lymph node volume did not predict the likelihood of nodal metastases (p = 0.4 and p = 0.07 for ipsilateral and contralateral nodal metastases, respectively), but primary tumor volume was significantly associated with the likelihood of nodal metastases (p = 0.001 and p = 0.005 for ipsilateral and contralateral nodal metastases, respectively). Ipsilateral metastases were detectable at a tumor diameter of 1 cm; contralateral metastases were more variable but in general required a tumor diameter of 2 cm. CONCLUSIONS: Rabbit transbronchial VX2 lung tumor models generate nodal metastases relatively early after inoculation. These results suggest such models may be valuable tools in the investigation of novel therapeutic modalities relevant for the treatment of both early-stage and locally advanced lung cancer.

Molecular Nodal Staging Using miRNA Expression in Lung Cancer Patients by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration.

BACKGROUND: The limited negative predictive value of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has often been discussed. OBJECTIVE: The aim of this study was to identify a highly sensitive molecular biomarker for lymph node staging by EBUS-TBNA. METHODS: Five microRNAs (miRNAs) (miR-200a, miR-200b, miR-200c, miR-141, and let-7e) were selected as biomarker candidates for the detection of nodal metastasis in a miRNA expression analysis. After having established a cutoff level of expression for each marker to differentiate malignant from benign lymph nodes among surgically dissected lymph nodes, the cutoff level was applied to snap-frozen EBUS-TBNA samples. Archived formalin-fixed paraffin- embedded (FFPE) samples rebiopsied by EBUS-TBNA after induction chemoradiotherapy were also analyzed. RESULTS: The expression of all candidate miRNAs was significantly higher in metastatic lymph nodes than in benign ones (p < 0.05) among the surgical samples. miR-200c showed the highest diagnostic yield, with a sensitivity of 95.4% and a specificity of 100%. When the cutoff value for miR-200c was applied to the snap-frozen EBUS-TBNA samples, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 97.4, 81.8, 95.0, 90.0, and 94.0%, respectively. For restaging FFPE EBUS- TBNA samples, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 100, 60.0, 80.0, 100, and 84.6%, respectively. Among the restaged samples, 4 malignant lymph nodes were false negative by EBUS-TBNA, but they were accurately identified by miR-200c. CONCLUSIONS: miR-200c can be used as a highly sensitive molecular staging biomarker that will enhance nodal staging of lung cancer.

Evaluating vertebral artery dominancy before T4 lung cancer surgery requiring subclavian artery reconstruction.

PURPOSES: To evaluate vertebral artery (VA) dominancy and the risk of brain infarction in T4 lung cancer patients with tumor invasion into the subclavian artery. METHODS: We reconstructed the subclavian artery in 10 patients with T4 non-small cell lung cancer. The histological stages were IIIA in eight patients and IIIB in two patients. We evaluated the VA dominancy by performing a four-vessel study preoperatively and investigated the relationship between the methods of VA treatment and postoperative brain complications, retrospectively. RESULTS: Seven patients had a superior sulcus tumor (SST) and three had direct invasion into the mediastinum. Based on the tumor location, a transmanublial approach was used in five patients and a posterolateral hook incision was used in the other five. All subclavian artery (SA) reconstructions were done using an artificial woven graft. Preoperative angiography of the VA revealed poor development of the contralateral side in two patients. One of these patients suffered a severe brain infarction on postoperative day 2, which proved fatal. In the other patient, the VA was connected to the left SA graft by a side-to-end anastomosis and there was no postoperative brain complication. CONCLUSIONS: Preoperative SA and VA angiography is mandatory for identifying the need for VA reconstruction in lung cancer patients with major arterial invasion.

Bronchial Embolization with an Endobronchial Watanabe Spigot for Broncho-Gastric Tube Fistula.

Anastomotic failure of a gastric tube inserted for reconstruction following esophagectomy, which is relatively rare, causes pleural infection and persistent pleural irritation, leading to communication with the pulmonary parenchyma. Although several interventions have been reported to treat such broncho-gastric tube fistulas, refractory cases remain. We herein report the successful treatment by endoscopic bronchial occlusion with an endobronchial Watanabe spigot in 2 patients who suffered from the above complication.

Mini grasping basket forceps for endobronchial foreign body removal in pediatric patients.

BACKGROUND: Appropriate device selection is crucial for endobronchial foreign body removal using a bronchoscope. In pediatric patients, bronchoscopy requires the use of a thin device due to the narrow access to the airway, limiting the range of useful endobronchial devices. We herein review our experience in endobronchial foreign body removal with a focus on the type of bronchoscope and the instruments used in comparison with the literature, and investigate the utility of mini grasping basket forceps (FG-55D, Olympus® ; and Zero Tip™ , Airway Retrieval Basket, Boston Scientific). METHODS: Between April 2008 and April 2016, foreign bodies were removed from the airway of 12 pediatric patients by bronchoscopy. These cases are reviewed in this study. The clinical presentation, location and characteristics of the foreign bodies, and the type of bronchoscope and instruments used were analyzed. RESULTS: A consecutive series of 12 pediatric patients was retrospectively reviewed, and the therapeutic characteristics investigated. Nuts were the most frequently observed foreign body. Seven of the 12 pediatric patients required an ultrathin bronchoscope (diameter, 2.8 mm) for foreign body removal. Only one patient required a rigid scope in addition to flexible bronchoscopy. The most frequently used instrument was a mini grasping basket forceps (n = 7; 58%), which was used with a 1.2 mm instrument channel (n = 4; 33%). CONCLUSIONS: The use of a mini grasping basket forceps in combination with an ultrathin flexible bronchoscope was useful for removing smooth, soft materials such as a nuts or beans in pediatric cases.

Elastography for Predicting and Localizing Nodal Metastases during Endobronchial Ultrasound.

BACKGROUND: Elastography is a relatively new technology that can generate images reflective of tissue stiffness (elasticity). Neoplastic tissue is usually stiffer than normal structures. OBJECTIVES: The aim of this study was to evaluate the feasibility and utility of elastography when combined with convex-probe endobronchial ultrasound (CP-EBUS) for predicting and localizing metastatic lymph nodes during endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA). METHODS: Consecutive results of endobronchial elastography of lymph nodes performed using EBUS- TBNA were prospectively collected and retrospectively analyzed. Elastography images were acquired as JPEG images and also recorded as video clips. Stiff area ratios [(stiff areas as blue pixels) / (lymph node areas as region of interest pixels)] for each lymph node determined by elastography were collated with the results of pathological diagnosis. We also performed elastography of surgically resected lymph nodes and compared image findings with pathological sections. RESULTS: We evaluated 49 lymph nodes in 21 patients by CP-EBUS. There were 16 metastatic nodes (10 lung cancer metastases and 6 metastases from extrathoracic malignancies). Mean stiff area ratios were significantly greater for metastatic lymph nodes (0.478) than for benign nodes (0.216; p = 0.0002). Using a cutoff value of 0.311 for stiff area ratios, the sensitivity and specificity for predicting metastatic disease were 0.81 and 0.85, respectively. The stiff area was histologically compatible with metastatic distribution in surgically resected lymph nodes. CONCLUSIONS: Endobronchial elastography is feasible for lymph nodes when combined with CP-EBUS. Stiff area ratios are useful for predicting metastatic lymph nodes, which may be an efficient guide for TBNA.

Surgery for Secondary Spontaneous Pneumothorax with Chronic Lung Diseases.

PURPOSES: Secondary spontaneous pneumothorax (SSP) is occasionally observed in elderly patients suffering from diffuse lung diseases. The purpose of this study was to analyze the outcomes of surgical treatment of SSP patients with chronic lung diseases. METHODS: In total, 242 patients who underwent surgery for spontaneous pneumothorax at Chiba University Hospital from January 2006 to October 2016 were included in this study. The patients' records were reviewed retrospectively for data on their background, surgical treatment, morbidity, mortality, and recurrence. RESULTS: Of the spontaneous pneumothorax cohort, primary spontaneous pneumothorax (PSP) accounted for 144 patients. Among the 98 patients with SSP, 57 cases were caused by chronic obstructive pulmonary disease (COPD) and 21 were caused by interstitial pneumonia (IP). The postoperative complication rate was 19.3% in the COPD group, 42.9% in the IP group, and 11.1% in the PSP group. The recurrence rate was 5.3% in the COPD group, 28.6% in the IP group, and 21.5% in the PSP group. CONCLUSIONS: The morbidity and recurrence were comparable between PSP and SSP cases with COPD, whereas these values were unfavorable in SSP cases with IP compared with PSP ones. Surgical intervention should be carefully considered in SSP patients with IP.

Can modified frailty index predict postoperative complication after lung cancer surgery?

PURPOSE: The impact of the modified frailty index (mFI) on postoperative complications after lung cancer surgery was investigated. METHODS: Patients who underwent lung cancer surgery in 2017 were included. 30-day postoperative mortality and morbidity were evaluated according to their Clavien-Dindo classification. mFI values are presented as the sum of values of 11 included items. Logistic regression was used to assess the effect of mFI on postoperative severe complication incidence. RESULTS: Among 190 patients considered, severe postoperative complications (Grade 3 or more) were observed in 30 (16%). No patients died within 30 days of surgery. The incidence of severe complications was 3.6% in patients with mFI of 0, 16.2% in patients with mFI of 1, 23.4% in patients with mFI of 2, and 31.6% in patients with mFI of 3 or more, and was correlated with the grade of mFI. Univariate and multivariate analyses showed that the high mFI was significantly predictive of postoperative complications. Frail patients of mFI ≥ 2 were at 3.0-fold greater risk of severe complications than non-frail patients of mFI 0 or 1. CONCLUSION: mFI was associated with morbidity after lung cancer surgery. Preoperative frailty assessment and appropriate intervention to frail patients would be required to improve postoperative outcomes.

What are the risk factors for postoperative home oxygen therapy in patients with lung cancer?

Background: Home oxygen therapy (HOT) is used to treat chronic respiratory diseases and is sometimes required in patients with lung cancer after radical surgery. We aimed to identify the risk factors for postoperative home-based oxygen therapy in patients with lung cancer. Methods: Patients who underwent surgery for primary lung cancer at Chiba University Hospital between January 2019 and March 2021 were included. Patients who did not undergo complete resection, died in hospital after surgery, or used oxygen therapy preoperatively were excluded. Eligible patients were divided into HOT and non-HOT groups. They were retrospectively analyzed for risk factors for postoperative HOT using medical records in a multivariate analysis. Results: A total of 410 patients were included in this study, 24 (5.9%) of whom required HOT after surgery. The HOT group comprised significantly more men, heavy smokers, and patients with pulmonary comorbidities, low percent forced expiratory volume, percent forced vital capacity, predicted postoperative forced expiratory volume in 1 s, and postoperative pulmonary complications on univariate analysis. In a multivariate analysis, independent risk factors for postoperative HOT were pulmonary comorbidities [odds ratio (OR): 5.94; 95% confidence interval (CI): 1.64-21.5; P=0.002) and postoperative pulmonary complications (OR: 5.39; 95% CI: 2.14-13.5; P<0.001). The postoperative HOT application rate was calculated according to a formula developed for this purpose. Conclusions: Comorbid pulmonary diseases and postoperative pulmonary complications were significantly associated with postoperative HOT in patients with lung cancer.

Optimization of thrombolytic dose for treatment of pulmonary emboli using endobronchial ultrasound-guided transbronchial needle injection.

OBJECTIVE: Severe pulmonary embolism is often managed with thrombolysis. We sought to determine whether endobronchial ultrasound (EBUS)-guided transbronchial thrombolysis remained effective at lower alteplase doses, with the goal of minimizing potential bleeding risk. METHODS: Yorkshire pigs were anesthetized and ventilated. Preformed autologous blood clots were administered into bilateral pulmonary arteries via EBUS-guided transbronchial injection. After documenting baseline clot sizes, alteplase was injected into the clots using a 25-gauge transbronchial needle and clot dissolution was monitored over 30 minutes. The study was performed in 2 phases. First, alteplase doses of 5 and 12.5 mg were evaluated. These results informed dose selection for the second phase. Results were compared with 25-mg dose data using EBUS from a previous study. RESULTS: In the first phase, 3 clots were evaluated. Distilled water, 5 mg, and 12.5 mg alteplase were administered. The dissolved clot volume (Vdis) and percentage clot volume loss (Rdis) were -10.9, 111.6, and 160.3 mm3, and -1.6%, 11.0%, and 59.3%, respectively. In the second phase, alteplase doses of 5, 10, and 15 mg were evaluated in 12 clots across 6 pigs. The Vdis were 247.5 mm3 (Rdis, 20.1%), 910.8 mm3 (Rdis, 80.9%), and 798.3 mm3 (Rdis, 76.0%) for 5, 10, and 15 mg alteplase, respectively. Remakably reduced performance was observed with 5 mg alteplase versus 10 mg (Vdis: P < .001, Rdis: P < .001), and 15 mg (Vdis: P = .004; Rdis: P < .001). No complications were observed. CONCLUSIONS: Alteplase doses ≥10 mg were optimal for EBUS-guided transbronchial thrombolysis. This technique might represent an effective alternative therapy for central pulmonary embolism.

Robot-assisted thoracic surgery versus video-assisted thoracic surgery for mediastinal lesions.

Background: Robot-assisted thoracic surgery (RATS) has become widely used for mediastinal procedures since 2018 when it was included in insurance coverage in Japan. Few studies have compared the surgical outcomes of RATS with the more established video-assisted thoracic surgery (VATS) approach to mediastinal surgery. We aimed to compare the perioperative outcomes of VATS and RATS to examine the advantages of the RATS approach in a single institutional cohort. Methods: A total of 144 patients who underwent VATS and 46 who underwent RATS mediastinal surgery between 2014 and 2022 were enrolled. We compared clinicopathological features such as age, sex, smoking history, respiratory function, surgical field, laterality, surgical procedure, board certification of the surgeon, and histology between the two groups. Perioperative outcomes including operation time, volume of blood lost, number of conversion cases to open surgery, duration of chest drainage, postoperative hospital stay, and postoperative complications were also reviewed. Results: The comparison of patient characteristics between the groups showed significant differences in median age (VATS, 52.5 years; RATS, 67.0 years; P=0.001), combined resection of surrounding tissues of the tumor (VATS, 2.1%; RATS, 10.9%; P=0.02), board certification of the surgeon (VATS, 53.5%; RATS, 100.0%; P<0.001), and histology (RATS group had a higher percentage of thymic epithelial tumors, P=0.01). Regarding perioperative outcomes, the median operation time was 120 min in the VATS group and 88 min in the RATS group, showing a significant difference (P=0.03). There were no significant differences in the volume of blood lost, incidence of conversion to open chest surgery, duration of chest drainage, postoperative length of stay in hospital, and incidence of perioperative complications. In the perioperative outcomes of cases operated on by board-certified surgeons, the median operation time (VATS, 117 min; RATS, 88 min; P=0.02) and median postoperative length of stay in hospital (VATS, 7 days; RATS, 6 days; P=0.001) showed significant differences, while other postoperative outcomes were not significantly different. Conclusions: RATS for mediastinal surgery is as safe as the VATS approach and may result in a shorter operative time and postoperative hospital stay. Further analysis of RATS for mediastinal surgery in a larger cohort is warranted.