INTRODUCTION:Precise spatial understanding of the bronchovascular tree is essential for anatomical lung resection. Three-dimensional (3D) reconstruction and extended-reality (XR) technologies have emerged as tools for preoperative planning, navigation, and education. We aimed to assess the current use and efficacy of 3D and XR technologies in thoracic surgery in Japan and develop expert recommendations. METHODS:Two clinical survey questions on the usefulness of 3D imaging in thoracic surgery and that of VR, AR, and MR were sent to 125 certified thoracic surgical centers. PubMed searches targeted thoracic 3D and XR studies, including English-language randomized, prospective, and retrospective studies, systematic reviews, and meta-analyses. Draft statements were refined at the Anatomy on the Border Expert Consensus Meeting (Japan Society for Endoscopic Surgery 2024). RESULTS:Fifty of the 125 institutions (40%) responded. 3D imaging was used by 96% of the institutions, and 72% used it in all cases. "Very" or "moderately" useful was reported by 94% of the institutions. Main purposes for using 3D imaging were preoperative simulation (84%) and anatomical understanding (86%); 52% of the institutions used 3D imaging for intraoperative reference. For XR, awareness was moderate, but adoption remained limited (8%). Among respondents, 74% rated its usefulness as uncertain, while only a small proportion found it clearly useful for preoperative simulation, intraoperative localization, and education. Literature search showed that 3D-planning reduces blood loss, operative time, and complications in segmentectomy, whereas XR studies demonstrated improved nodule localization and workflow efficiency. CONCLUSIONS:3D imaging should be the standard for complex thoracic resections, particularly segmentectomy. XR is a promising tool, with broader deployment expected as its usability improves and cost decreases.

Background:The temporal distribution of postoperative recurrence in patients with resected epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer remains incompletely characterized. Most prior studies have focused on aggregate survival endpoints without explicitly modeling time-dependent recurrence hazards, thereby potentially obscuring underlying temporal patterns. A formal characterization of recurrence hazard over time may provide insight into the natural history of EGFR-mutant disease and inform postoperative management strategies, particularly in the current era of adjuvant EGFR-tyrosine kinase inhibitors (TKIs). Here, we aimed to evaluate the temporal dynamics of postoperative recurrence in a treatment-naïve multicenter cohort of patients with completely resected stage II-III lung adenocarcinoma. Understanding the intrinsic timing of recurrence is also essential for interpreting outcomes of recent adjuvant EGFR-TKI trials and for designing future time-adapted postoperative strategies. Methods:We conducted a multicenter retrospective cohort study including 787 patients (295 EGFR-mutant and 492 EGFR-wild-type) who underwent complete resection between 2010 and 2020 at four Japanese institutions, all in the pre-adjuvant EGFR-TKI era. Cumulative incidence of recurrence and lung cancer-related death was estimated using competing-risk methods, treating non-cancer-related death as a competing event. Between-group differences were assessed using Gray's test, and subdistribution hazard ratios were estimated using the Fine-Gray model. Temporal changes in recurrence hazard were evaluated using Joinpoint regression, and interval-specific competing-risk analyses were performed. Propensity score matching using preoperative variables was applied as a sensitivity analysis. Results:With a median follow-up of 62 months, the 5-year cumulative incidence of recurrence (53% vs. 44%; P=0.20) and lung cancer-related death (29% vs. 32%; P=0.40) did not differ significantly between EGFR-mutant and EGFR-wild-type tumors. However, recurrence hazard in patients with EGFR-mutant disease showed a distinct nonlinear temporal pattern. Joinpoint regression identified a significant inflection point at approximately 3 years after surgery (P=0.002), beyond which recurrence hazard declined markedly (annual percent change: -34.64%), following a relatively sustained risk phase during the earlier postoperative period. In contrast, no clear inflection point was observed in patients with EGFR-wild-type tumors. Interval-specific analyses revealed no significant differences in recurrence hazard between the groups at any postoperative interval, suggesting that the observed pattern reflects an intrinsic temporal structure rather than differences in overall risk magnitude. This time-dependent pattern was consistently observed across clinically relevant subgroups and remained unchanged after propensity score matching. Conclusions:Postoperative recurrence in patients with EGFR-mutant stage II-III lung adenocarcinoma exhibits a nonlinear, time-structured hazard pattern characterized by an early concentration of risk followed by attenuation beyond 3 years. These results are particularly relevant in the current era of adjuvant EGFR-TKI therapy, where the optimal duration of treatment and surveillance remains uncertain in clinical practice. A clearer understanding of intrinsic recurrence timing may help refine future time-adapted postoperative strategies.

OBJECTIVES:Intraoperative assessment of resection margins during pulmonary resection is limited by tissue compression and distortion caused by conventional staplers, which hinder direct pathological evaluation of the anatomical resection margin. We report our initial clinical experience with a novel asymmetric linear stapler (NALS) designed to provide direct access to the specimen-side anatomical resection margin for intraoperative histologic assessment. METHODS:We retrospectively reviewed patients who underwent pulmonary resection using the NALS between July 2024 and December 2025. Intraoperative frozen-section examination was performed for parenchymal and/or bronchial margins when malignancy was suspected or confirmed. Margin status, margin distance, and frozen-permanent pathological concordance were analysed descriptively. RESULTS:Among 226 patients who underwent pulmonary resection using the NALS, 206 resection margins (144 parenchymal and 62 bronchial) were evaluated. Intraoperative frozen-section examination identified margin positivity in 12 margins (5.8%). Residual tumour was confirmed on permanent pathology in 4 of 8 parenchymal frozen-positive margins, whereas all bronchial frozen-positive margins showed benign or reactive changes. No false-negative frozen-section findings were identified. Among negative margins with available measurements, 66.7% of parenchymal margins and 84.5% of bronchial margins measured at least 10 mm. CONCLUSIONS:In this initial experience, intraoperative margin assessment using the NALS was feasible and enabled structured evaluation of the anatomical resection margin during pulmonary resection. Because no control group using conventional staplers was included, these findings should be interpreted as a feasibility assessment rather than evidence of superiority over standard stapling devices. Further multicentre studies with controlled comparisons and long-term oncologic follow-up are warranted.

Background: Predicting long-term outcomes after pulmonary metastasectomy for colorectal cancer remains challenging because existing prognostic methods lack precision. We developed and validated a prognostic scoring system derived from a major international meta-analysis to improve risk stratification and to evaluate the benefit of adjuvant chemotherapy across risk groups. Methods: Using a Japanese registry of 819 patients who underwent lung resection between 2010 and 2019, we constructed a 0-13-point score based on eight variables including tumor size, number, biological markers, and intrathoracic lymph node status, which may require intraoperative or pathological confirmation. Granular data on chemotherapy regimens, timing, and duration were unavailable. Patients were classified as low, intermediate, or high risk. The primary analysis used inverse probability of treatment weighting to adjust for baseline imbalances; however, only 819 of 1657 patients (49.4%) had complete prognostic data, introducing potential selection bias. Results: The score separated patients into three groups with distinct five-year survival rates: 81.1% (low), 67.8% (intermediate), and 59.1% (high). In high-risk patients, chemotherapy was associated with improved overall survival but did not delay recurrence. In low-risk patients, chemotherapy correlated with reduced recurrence-free survival, a finding that persisted after adjustment. Conclusions: This validated scoring system aids individualized surgical decision making by identifying patients unlikely to benefit from routine postoperative chemotherapy. Observed survival advantages in high-risk patients may reflect selection of fitter individuals rather than direct treatment effects, underscoring the need to address selection bias in future trials.

INTRODUCTION:To evaluate staple formation according to endostapler cartridge type and bronchial wall thickness in patients undergoing pulmonary lobectomy. METHODS:We prospectively enrolled patients scheduled to undergo lower lobectomy. The bronchus was divided by using an endostapler (ECHELON FLEX Powered Plus Stapler). The cartridge (gold, green, or black) was selected at the surgeon's discretion. After measuring the bronchial stump thickness, the bronchial tissue was proteolyzed, and all staple formations were scored from 1 to 3 points, with 3 representing an approximately perfect B-shaped staple. RESULTS:Eighty patients were enrolled. Gold, green, and black cartridges were used in 26, 49, and five patients, respectively. Green/black cartridges were used more frequently in patients with thicker bronchial stumps (p = 0.001) than gold. The mean staple formation score tended to be higher for green/black than gold cartridges (p = 0.087). The proportion of scores ≥ 2 was equivalent (p = 0.766). The proportion of score 3 was higher for green/black than gold cartridges (p < 0.001). Bronchial stump thickness significantly correlated with sex (p < 0.001) and height (p = 0.001). For men and women > 160 cm in height, the mean score tended to be higher for green/black than gold cartridges (p = 0.068). No postoperative bronchopleural fistulae were observed. CONCLUSIONS:Although each cartridge performed well, ensuring tissue apposition and good clinical outcomes, green or black cartridges appeared to be more appropriate than gold for the lower bronchus, especially in men and women > 160 cm in height. TRIAL REGISTRATION:UMIN000043969.

Objective: Current guidelines recommend 10% neutral-buffered formalin (NBF) for tissue processing in genomic medicine. However, supporting evidence is derived predominantly from non-pulmonary specimens, and lung-specific validation is lacking. Lung tissue's pleural barrier and post-resection collapse may impede uniform fixative penetration. We evaluated whether a workflow incorporating early refrigeration and 20% NBF consistently enabled multiplex genomic testing in surgically resected lung cancer. Patients and Methods: Thirty patients with resected stage IA3–IIIA non-small cell lung cancer were prospectively enrolled. Specimens were refrigerated immediately after resection and fixed with 20% NBF via transbronchial or parenchymal injection. Rapid intraoperative specimens fixed in 10% NBF served as a contextual reference. The primary endpoint was the success rate of the Oncomine™ Dx Target Test (ODxTT), with nucleic acid quality assessed against manufacturer thresholds. Results: ODxTT was successfully completed in all surgical specimens (100%). All exceeded minimum thresholds (DNA ≥0.83 ng/μL; RNA ≥1.43 ng/μL). Although DNA integrity and RNA quality differed between contextual references and surgical specimens, all specimens remained suitable for ODxTT analysis. Concordance with single-plex testing was 93% for epidermal growth factor receptor mutations and 100% for anaplastic lymphoma kinase rearrangements. Multiplex testing succeeded despite fixation durations frequently exceeding current recommendations. Conclusions: Fixation with 20% NBF was compatible with multiplex genomic testing with high assay success under real-world conditions. Organ-adapted fixation strategies may represent a feasible option for lung specimens, particularly where strict adherence to a single fixation standard is difficult to sustain in routine practice, and lung-specific validation of fixation standards is warranted.

214 Background: Pulmonary metastasectomy (PM) is a curative treatment option for colorectal cancer (CRC) patients with lung metastases. While several clinical and molecular factors such as RAS / BRAF mutations (MTs) have been reported as poor prognostic markers, few large-scale studies have comprehensively assessed these variables. Methods: We retrospectively analyzed 441 CRC patients who underwent PM at our hospital between January 2015 and December 2024. Follow-up continued until April 30, 2025. Clinical and molecular data were collected, including age, sex, performance status (PS), smoking history, resection type, primary tumor location, RAS / BRAF V600E MTs status, the number and size of lung metastases, and preoperative carcinoembryonic antigen (CEA) levels. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan–Meier method. Prognostic factors were evaluated using univariate and multivariate Cox proportional hazards models. Results: Among 441 patients, median DFS was 31.0 months (95% CI: 19.0-not reached), and median OS was not reached (19.0-NR). RAS / BRAF V600E MTs status was assessed in 347 patients; RAS / BRAF wild type (WT): n=157 (45.2%), RAS MTs: n=184 (53.0%; KRAS : n=173, NRAS : n=11), BRAF V600E MTs: n=6 (1.7%). Median DFS was 22.8 months (14.2-NR) in WT, 31.0 months (13.2-NR, HR: 0.97, 95% CI, 0.72-1.30, p=0.83) in RAS MTs, 9.5 months (2.9-44.7, HR: 2.65, 1.15-6.13, p=0.023) in BRAF V600E MTs; median OS was not reached (19.0-NR), 98.6 months (83.2-NR, HR: 1.43, 0.88-2.30, p=0.15), 37.8 months (20.9-NR, HR: 7.52, 2.54-22.3, p<0.01), respectively. Clinical characteristics were broadly similar across groups, except for primary tumor location; right-sided primaries were more common in BRAF V600E MTs cases (66.7%, p<0.01). In multivariate analysis, elevated preoperative CEA (HR: 2.24, 95%CI 1.58-3.19, p<0.01), BRAF V600E MTs (HR: 1.64, 1.09-2.47, p=0.018), RAS MTs (HR: 1.58, 1.05-2.36, p=0.027), and ≥2 lung tumors (HR: 1.40, 1.17-1.66, p<0.01) were independently associated with shorter DFS. For OS, multivariate analysis showed that PS=1 (HR: 3.57, 1.90-6.69, p<0.01) and elevated preoperative CEA (HR: 2.32, 1.40-3.85, p<0.01) were associated with shorter OS. Conclusions: Both RAS / BRAF MTs increase the risk of recurrence following PM, consistent with their prognostic role in other disease stages. Integration of these mutations with clinical factors such as preoperative CEA levels and the number of lung metastases enables a more comprehensive risk assessment for postoperative management strategies. Multivariate Cox analysis. Variable HR 95% CI p-value DFS CEA ≥5 ng/mL (vs. <5) 2.24 1.58–3.19 <0.01 BRAF V600E MTs (vs. RAS / BRAF WT) 1.64 1.09–2.47 0.018 RAS MTs (vs. RAS / BRAF WT) 1.58 1.05–2.36 0.027 ≥2 lung tumors (vs. single) 1.40 1.17–1.66 <0.01 OS PS = 1 (vs. 0) 3.57 1.90–6.69 <0.01 CEA ≥5 ng/mL (vs. <5) 2.32 1.40–3.85 <0.01

Pancreatic carcinoma (PC) and biliary tract carcinoma (BTC) may metastasize to the lungs, and surgical resection of these metastases should be considered in selected patients with controlled primary disease. This study evaluated the survival outcomes and prognostic factors in patients who underwent pulmonary metastasectomy for pancreatobiliary carcinoma. Seventy-eight patients who underwent lung metastasectomy between 1993 and 2019 were included in the Metastatic Lung Tumor Study Group of the Japan database. The clinicopathological characteristics including overall survival (OS), pulmonary metastasis-free survival (PmFS), and disease-free interval (DFI) from primary surgery to lung metastasectomy were analyzed. We included 41 men and 37 women with a mean age of 67 years. The primary cancers included 56 PC and 22 BTC cases. Partial resection was performed in 52 patients, segmentectomy in 16, and lobectomy in 10. Five-year OS was 38.3

This study evaluated the incidence and clinical impact of radiation pneumonitis (RP) in patients with unresectable stage III non-small cell lung cancer (NSCLC) treated with durvalumab following concurrent chemoradiotherapy (CCRT), with a particular focus on durvalumab interruption, re-administration, and overall survival (OS). This retrospective study included patients treated at our institution between April 2018 and June 2024. Durvalumab was administered for up to one year or until discontinuation due to adverse events or disease progression. RP was graded according to CTCAE version 5.0. Associations between grade ≥ 2 RP and clinical or treatment-related factors were assessed using univariate and multivariate analyses. Survival outcomes were analyzed using the Kaplan–Meier method and Cox proportional hazards models. Among 101 patients, 48 (47.5

Li-Fraumeni syndrome (LFS), caused by pathogenic germline TP53 variants, is increasingly recognized as a predisposition to lung adenocarcinoma (LUAD); however, its clinical features remain insufficiently defined. Patients diagnosed with LFS at our institution between 2000 and 2025 were retrospectively reviewed, and five patients with primary LUAD were identified among 32 individuals with LFS. The median age at diagnosis was 34 years (range, 29-53 years), and four patients had never smoked. Three patients had a family history of lung cancer, and three had multiple synchronous lung lesions. Notably, activating EGFR alterations were identified in all four tested cases. The clinical course was heterogeneous: one patient with advanced disease achieved ongoing disease control with lazertinib plus amivantamab, whereas another patient achieved prolonged benefit from sequential EGFR tyrosine kinase inhibitors, with 34 months on gefitinib and 51 months on osimertinib after the acquisition of EGFR T790M. In contrast, surveillance of a patient with previously recognized LFS led to the detection of two early-stage lung cancers, followed by curative-intent surgery and a favorable postoperative course. Two of the five patients did not fulfill the 2015 Chompret criteria. These exploratory findings suggest that LFS-associated LUAD may be under-recognized and characterized by early-onset presentation and never-smoking status, multifocal disease, and frequent EGFR alterations, warranting validation in larger cohorts.

BACKGROUND:Adjuvant chemotherapy (Adj) reduces recurrence and improves long-term survival in patients with surgically resected lung cancer. However, it has minimal impact on patients who die without relapsing. To optimize Adj indications, we aimed to identify factors associated with nonrelapse mortality (NRM). PATIENTS AND METHODS:This multicenter, retrospective, observational study enrolled patients with surgically resected with stages II-III non-small cell lung cancer. Multivariable Cox regression analysis was performed to identify the factors associated with NRM and early-NRM within 2 years of surgery and to stratify the enrolled patients. Adj administration rates and postoperative overall and recurrence-free survival rates were compared. Multivariable competing regression analysis with NRM as a competing risk was used to assess the cumulative incidence of lung cancer-associated death and recurrence. RESULTS:Through a scoring system assigning 1 point to each extracted factor (old age, male sex, poor performance status, nonadenocarcinoma, and occurrence of major complications), the 1,244 included patients were stratified into 3 groups based on scores of 0-5: A (0-1 points; n = 613), B (2-3 points; n = 549), and C (4-5 points; n = 62) with 53%, 26%, and 11% Adj administration, respectively. Although group A showed the highest overall and recurrence-free survival rates, competing regression analysis showed no significant differences in cumulative lung cancer-associated death and recurrence incidence between the groups. CONCLUSION:Better prognosis in group A was attributed to lower NRM and higher Adj administration rates. While proactive Adj may benefit group A, careful evaluation is warranted for group C to optimize Adj indication.

INTRODUCTION:Thymomas have the potential to locally invade and metastasize, occasionally infiltrating adjacent structures, such as the great vessels and the heart. Although direct extension is the primary mechanism of vascular invasion, rare cases of intravascular growth have also been reported. CASE PRESENTATION:We present the case of a 50-year-old woman diagnosed with a thymoma that extended intraluminally into the left brachiocephalic vein (LBCV), forming a tumor thrombus. The patient was referred to our hospital after chest computed tomography (CT), which revealed an anterior mediastinal tumor with a filling defect adjacent to the superior aspect of the tumor. Initially, the defect was thought to be a blood clot because of the preserved vascular wall structure. However, follow-up CT scans conducted 2 weeks later revealed persistence of the defect and a slight increase in size, leading to the diagnosis of a tumor thrombus. Further imaging, including contrast-enhanced CT and magnetic resonance imaging, confirmed thymoma invasion of the LBCV, necessitating surgical intervention. The patient underwent a median sternotomy and tumor resection with combined partial resection of the LBCV and right upper lobe. Intraoperatively, a dilated thymic vein continuous with the tumor was identified. The tumor thrombus was visible through the LBCV wall, aiding in the determination of its extent. The LBCV was clamped proximally and distally, and the dilated thymic vein was ligated and divided. Subsequently, thymectomy encompassing the tumor and partial resection of the LBCV wall were performed to remove the thrombus. Microscopically, the tumor was classified as a type B2 thymoma. No evidence of continuity between the tumor thrombus and the thymic vein was observed. No postoperative complication was observed. Nine months after surgery, the patient experienced recurrence with pleural dissemination and underwent resection. CONCLUSIONS:Thymomas can invade vessels through intravascular growth, and contrast-enhanced CT is important for accurately diagnosing such cases. In this instance, preoperative identification of the tumor thrombus enabled a comprehensive surgical approach, resulting in complete resection of the tumor and thrombus, without the need for embolization. This case underscores the significance of meticulous imaging and surgical planning in the management of complex thymomas to ensure optimal patient outcomes.

BACKGROUND/AIM:Pulmonary metastases (PMs) from ovarian cancer are rare, and the efficacy of surgical intervention is unclear. This study aimed to validate the efficacy of surgical intervention for pulmonary metastases from ovarian cancer. PATIENTS AND METHODS:Cases were taken from the database of the Metastatic Lung Tumor Study Group of Japan from 1996 to 2021, which prospectively registers surgical cases of pulmonary metastases at participating centers. Only patients who underwent radical surgery for pulmonary metastases from ovarian cancer were included. Factors associated with overall survival (OS) were analyzed. RESULTS:The analysis included 48 patients with a mean age of 53.2 years old. The 5-year overall survival rate was 69.9% [95% confidence interval (CI)=51.9%-82.2%], with a median survival period of 121 months (95% CI=64-134 months). Predictors of poorer OS included preoperative extrapulmonary metastasis [hazard ratio (HR)=5.354, 95% CI=1.248-22.97; p=0.024], elevated preoperative tumor marker levels (HR=2.999, 95% CI=1.028-8.705; p=0.044), and a disease-free interval of less than 24 months (HR=4.355, 95% CI=1.004-18.89; p=0.049). On multivariable analysis, preoperative extrapulmonary metastasis remained an independent prognostic factor (HR=6.229, 95% CI=1.216-31.92; p=0.028). CONCLUSION:This report includes the largest number of patients who underwent resection of PMs from OC. Preoperative extrapulmonary metastasis was identified as an adverse prognostic factor, emphasizing the need for careful consideration of surgical indications. Our results significantly contribute to understanding the prognosis and prognostic factors associated with surgical intervention for PMs from OC.

INTRODUCTION:The liver, lungs, and kidneys are all parenchymal organs and are useful targets for indocyanine green (ICG) fluorescence. We created a consensus statement on the appropriate use and precautions for ICG in liver, lung, and kidney surgery. METHODS:We conducted a comprehensive literature search and questionnaire survey for expert surgeons in each area. RESULTS:We extracted 11 articles related to the liver, 23 to the lung, and 8 to the kidney. A total of 86 facilities, 50 facilities, and 32 surgeons responded to the questionnaire survey for the liver, lung, kidney, respectively. ICG fluorescence is widely employed for segment delineation of the liver, lung, and kidney and has been reported to exhibit high efficacy. The dosage and timing greatly vary depending on the target organ and administration route. Tumor localization via ICG fluorescence is widely performed in the liver area, with numerous reports highlighting its high efficacy. Contrarily, in the lung and kidney, despite the existence of clinical studies, ICG fluorescence has not been generally performed in clinical practice. There have been no reported complications or adverse experiences related to the use of ICG agents, indicating their safety for clinical use. CONCLUSION:This survey, along with a literature review, has elucidated the current consensus of liver, lung, and kidney surgeons regarding ICG fluorescence.

Introduction Advancements in minimally invasive robot-assisted surgery have considerably improved the precision of anatomical recognition. Nonetheless, variations in anatomical interpretation persist among surgical specialties, particularly in overlapping regions such as the thoracic cavity. This study aimed to elucidate differences in nerve recognition between esophageal and thoracic surgeons in Japan.Methods A questionnaire-based survey was conducted as part of the "Anatomy on the Border" initiative by the Japan Society for Endoscopic Surgery. Responses were obtained from 78 esophageal surgical institutions (57%) and 62 thoracic surgical institutions (49%). The survey included seven items related to nerve identification, challenges in visualization, and techniques for nerve preservation.Results Nearly all respondents deemed recurrent laryngeal nerve identification to be important or very important. Esophageal surgeons had higher recognition rates for the esophageal branches and recurrent laryngeal nerve, whereas thoracic surgeons more frequently identified the phrenic nerve, sympathetic trunk, and pulmonary branches of the vagus nerve. Nerve injury prevention strategies also differed: esophageal surgeons commonly performed nerve integrity monitoring and were more selective with energy devices, whereas thoracic surgeons emphasized anatomical knowledge. The rate of nerve integrity monitoring usage was notably higher in esophageal surgery (40%) than in thoracic surgery (11%).Conclusion This cross-disciplinary study highlights different approaches and perceptions regarding nerve identification in thoracic surgery. The promotion of dialogue and knowledge sharing between esophageal and thoracic surgeons can potentially improve anatomical understanding and surgical safety.

BACKGROUND:This study aimed to explore the commonalities and differences in systematic lymph node dissection between lung and esophageal cancer surgeries. METHODS:A survey comprising 11 questions related to systematic lymph node dissection techniques for both lung and esophageal cancer was conducted across 265 facilities specializing in thoracic and esophageal surgeries. Additionally, a comprehensive search was performed using the MEDLINE database. RESULTS:Responses were received from 63 facilities specializing in thoracic surgery and 79 facilities specializing in esophageal surgery. Many facilities chose minimally invasive surgery for lung and esophageal cancer. Most thoracic and esophageal surgeons paid attention to the concepts of visceral and vascular sheaths. The results of the survey and literature review revealed the key anatomical structures that define the area of mediastinal lymph node dissection. CONCLUSION:This survey and the literature review have clarified the current consensus among thoracic and esophageal surgeons regarding systematic mediastinal lymph node dissection.

INTRODUCTION:Although mediastinal lymph node dissection is performed in both lung and esophageal cancer surgeries, the underlying concepts and indications may differ between these fields. This study aimed to clarify these differences through a nationwide questionnaire survey initiated by the 37th Annual Meeting of the Japan Society for Endoscopic Surgery. METHODS:A joint task force from the lung and esophageal surgery divisions developed a questionnaire focusing on four key areas: (i) lymph node dissection around the left recurrent nerve, (ii) subcarinal lymph node dissection, (iii) pulmonary ligament lymph node dissection, and (iv) en bloc lymph node dissection. The survey was distributed to certified core institutions across Japan. RESULTS:The response rates were 50.4% for lung cancer institutions and 57.0% for esophageal cancer institutions. In the esophageal division, dissection of the aforementioned lymph nodes was routinely performed in most core institutions. In contrast, practices in the lung division varied widely, particularly depending on tumor location. The concept of "sampling" was rarely recognized in esophageal surgery but was partially accepted in lung surgery. Furthermore, there was no uniform definition of "en bloc dissection" across either field. CONCLUSION:This cross-sectional survey revealed notable conceptual differences between lung and esophageal cancer divisions regarding mediastinal lymph node dissection, despite targeting the same anatomical regions. Additionally, significant variability was observed even within the lung division. These findings indicate a lack of standardized consensus in Japan and highlight the need for ongoing cross-disciplinary dialog and consensus building.