A comparative study of robot-assisted thoracoscopic surgery and conventional approaches for short-term outcomes of anatomical segmentectomy.

OBJECTIVES: Since anatomical segmentectomy requires meticulous dissection of the segmental pulmonary vessels and bronchus, robot-assisted thoracoscopic surgery (RATS) has been widely adopted in recent years. We investigated the usefulness of RATS segmentectomy by comparing perioperative outcomes with conventional approaches including open thoracotomy or video-assisted thoracoscopic surgery (VATS). We compared perioperative outcomes of segmentectomy between RATS and conventional approaches including open thoracotomy or video-assisted thoracoscopic surgery (VATS). METHODS: This single-institutional retrospective study comprised 231 patients with primary lung cancer who underwent segmentectomy by RATS or conventional approaches between January 2011 and December 2022. Surgical outcomes and postoperative complications were analyzed among patients whose background factors were adjusted by propensity score matching (PSM). RESULTS: Before PSM, there were significant differences in age, smoking status, and types of segmentectomy. After PSM, 126 patients (63 patients in each group) were included in this analysis. The RATS group had significantly shorter operative time (154 vs 210 min; p < 0.01), fewer bleeding amounts (10 vs 40 mL; p < 0.01), and shorter duration of chest drainage (2 vs 2 days; p = 0.04) than the conventional-approach group. There was no significant difference in the incidence of all complications; however, the incidence of postoperative pneumonia was significantly lower than in the conventional-approach group (p = 0.02). CONCLUSIONS: RATS segmentectomy is proposed to be useful. It was suggested that RATS segmentectomy may be useful with better perioperative results than the conventional approach. Further studies on oncological long-term outcomes and cost-benefit comparisons are needed.

The consecutive impact of COVID-19 on thoracic surgical procedures in Japan: an analysis of data from the National Clinical Database.

PURPOSE: The current study was designed to analyze the impact of the COVID-19 pandemic on general thoracic surgeries in Japan. METHODS: Changes in surgeries for lung cancer and metastatic lung tumors were evaluated based on National Clinical Database data regarding cancer screening. RESULTS: In 2021, surgeries for primary lung cancer increased by 3.4% compared to 2020, which, given the increase from 2014 to 2019, indicates an overall 11.1% decrease. In contrast, surgeries for metastatic lung tumors in 2021 decreased by 5.8% compared to 2020, which, given the increase from 2014 to 2020, indicates an overall 9.2% decrease. Half of the primary diseases for metastatic lung tumor were cases of colorectal cancer. Low anterior resection procedures in 2020 decreased by 5.5% compared to 2019. Lung and colon cancer screening examinees in 2021 were increased compared to 2020; however, they still showed respective decreases of 11% and 9.0% compared to 2019. CONCLUSIONS: Surgeries for primary lung cancer still decreased substantially during the COVID-19 pandemic. The continued stagnation of screening was responsible for this decrease. Surgeries for metastatic lung tumors decreased profoundly, and the decrease in screening for primary tumors was responsible for this reduction. Our findings emphasize the significance of maintaining cancer screening efforts, even during a pandemic.

Typical carcinoid in right middle lobe of pulmonary hypoplasia.

BACKGROUND: Pulmonary typical carcinoid occurring in hypoplasia of the right middle lobe is very rare. CASE PRESENTATION: A routine examination's chest X-ray revealed an abnormal shadow in the right middle lung field of an 82-year-old Japanese woman. A chest computed tomography scan showed a solid 2.5 × 2.0-cm nodule in the very small right middle lobe. A trans-bronchial lung biopsy of the mass in the right middle lobe was performed; it revealed atypical cells with round nuclei growing in multiple foci, and immunostaining was positive for chromogranin A, synaptophysin and CD56, suggesting pulmonary carcinoid. The preoperative clinical diagnosis of primary lung cancer, cT1cN0M0 stage IA3 was considered. A right middle lobectomy and mediastinal lymph node dissection were performed by video-assisted thoracic surgery. Intraoperatively, the middle lobe of the right lung was very small, with 1- to 2-mm-dia. pulmonary arteries and veins that were considered hypoplastic. The final histopathological diagnosis was typical carcinoid, pT2aN0M0 stage IB based on the presence of pleural invasion. CONCLUSIONS: Including the present patient, only nine cases of lung cancer occurring within pulmonary hypoplasia have been reported, most of which were typical carcinoid.

Dynamic transition of molecular subtypes in relapsed small cell lung cancer treated with multimodal therapy: A case report.

Several transcription factors in small cell lung cancer (SCLC), including achaete-scute homolog 1 (ASCL1) and neurogenic differentiation factor 1 (NEUROD1), contribute to rapid tumor growth and early metastatic dissemination. Recent studies suggested that these molecular subtypes represent neuroendocrine differentiation in dynamic SCLC evolution. In the present case, a 62-year-old man was diagnosed with limited disease SCLC originating from the right upper lobe. Biopsy specimens were positive for ASCL1 but negative for NEUROD1. Six months after concurrent chemoradiotherapy and prophylactic cranial irradiation, the primary tumor had regrown and salvage surgery was performed. The pathological diagnosis was recurred SCLC, and postoperative histopathology was positive for both ASCL1 and NEUROD1. The patient was subsequently followed up; however, he had multiple bone metastases 9 months after surgery. It was speculated that the shift to NEUROD1-high expression in tumor cells surviving concurrent chemoradiation therapy may be related to the poor outcome after combined modality treatment.

Randomized phase II study of daily versus alternate-day administrations of S-1 for the elderly patients with completely resected pathological stage IA (tumor diameter > 2 cm)-IIIA of non-small cell lung cancer: Setouchi Lung Cancer Group Study 1201.

BACKGROUND: It is shown that the postoperative adjuvant chemotherapy for non-small cell lung cancer (NSCLC) was associated with survival benefit in an elderly population. We aimed to analyze the feasibility and efficacy of alternate-day S-1, an oral fluoropyrimidine, for adjuvant chemotherapy in elderly patients with completely resected pathological stage IA (tumor diameter > 2 cm) to IIIA (UICC TNM Classification of Malignant Tumours, 7th edition) NSCLC. METHODS: Elderly patients were randomly assigned to receive adjuvant chemotherapy for one year consisting of either alternate-day oral administration of S-1 (80 mg/m2/day) for 4 days a week (Arm A) or a daily oral administration of S-1 (80 mg/m2/day) for 14 consecutive days followed by 7-day rest (Arm B). The primary endpoint was feasibility (treatment completion rate), which was defined as the proportion of patients who completed the allocated intervention for 6 months with a relative dose intensity (RDI) of 70% or more. RESULTS: We enrolled 101 patients in which 97 patients received S-1 treatment. The treatment completion rate at 6 months was 69.4% in Arm A and 64.6% in Arm B (p = 0.67). Treatment completion rate in Arm B tended to be lower compared to Arm A, as the treatment period becomes longer (at 9 and 12 months). RDI of S-1 at 12 months and completion of S-1 administration without dose reduction or postponement at 12 months was significantly better in Arm A than in Arm B (p = 0.026 and p < 0.001, respectively). Among adverse events, anorexia, skin symptoms and lacrimation of any grade were significantly more frequent in Arm B compared with Arm A (p = 0.0036, 0.023 and 0.031, respectively). The 5-year recurrence-free survival rates were 56.9% and 65.7% for Arm A and B, respectively (p = 0.22). The 5-year overall survival rates were 68.6% and 82.0% for Arm A and B, respectively (p = 0.11). CONCLUSION: Although several adverse effects were less frequent in Arm A, both alternate-day and daily oral administrations of S-1 were demonstrated to be feasible in elderly patients with completely resected NSCLC. TRIAL REGISTRATION: Unique ID issued by UMIN: UMIN000007819 (Date of registration: Apr 25, 2012) https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000009128. Trial ID issued by jRCT: jRCTs061180089 (Date of registration: Mar 22, 2019, for a shift toward a "specified clinical trial" based on Clinical Trials Act in Japan) https://jrct.niph.go.jp/en-latest-detail/jRCTs061180089.

Sublobar Resection for Non-Small Cell Lung Cancer in Octogenarians: A Prospective, Multicenter Study.

BACKGROUND: Segmentectomy is a good surgical option for peripheral, early, non-small cell lung cancer (NSCLC) ≤2 cm. However, the role of sublobar resection including wedge resection and segmentectomy remains unclear for octogenarians with >2-cm but ≤4-cm early-stage NSCLC, for which lobectomy is a standard treatment. METHODS: By use of a prospective registry, 892 patients aged ≥80 years with operable lung cancer were enrolled at 82 institutions. Of these, we analyzed the clinicopathologic findings and surgical outcomes of 419 patients with NSCLC tumors of 2 to 4 cm during a median follow-up of 50.9 months between April 2015 and December 2016. RESULTS: Five-year overall survival (OS) was slightly but not significantly worse after sublobar resection than after lobectomy in the entire cohort (54.7% [95% CI, 43.2%-93.0%] vs 66.8% [95% CI, 60.8%-72.1%]; P = .09). Multivariable Cox regression analysis of OS revealed that these surgical procedures were not independent prognostic predictors (hazard ratio, 0.8 [0.5-1.1]; P = .16). The 5-year OS was comparable between 192 patients who could tolerate lobectomy but were treated by sublobar resection or lobectomy (67.5% [95% CI, 48.8%-80.6%] vs 71.5% [95% CI, 62.9%-78.4%]; P = .79). Recurrence after sublobar resection and lobectomy was locoregional in 11 (11%) of 97 and in 23 (7%) of 322 patients, respectively. CONCLUSIONS: OS might be equivalent between sublobar resection with a secure surgical margin and lobectomy for selected patients aged ≥80 years with peripheral early-stage NSCLC tumors of 2 to 4 cm who can tolerate lobectomy.

Clinical significance of MYC family protein expression in surgically resected high-grade neuroendocrine carcinoma of the lung.

OBJECTIVES: MYC family genes including MYC, MYCN, and MYCL are amplified and overexpressed as oncogenic drivers in high-grade neuroendocrine carcinoma of the lung (HGNEC), but little is known about their clinical significance. This study evaluated the prognostic impact of MYC family protein expression in patients with surgically resected HGNEC. METHODS: Immunohistochemical analyses were performed on 83 resected specimens of HGNEC using antibodies against MYC family proteins (c-MYC, n-MYC, and l-MYC). When nuclear staining of any intensity in ≥10% of tumor cells showed immunoreactivity with any one or more of c-MYC, n-MYC, or l-MYC, the specimens were defined as MYC family-positive. RESULTS: A total of 83 patients were analyzed. MYC family-positive status was observed in 33.7% (28 of 83 cases) and was not correlated with clinicopathological factors. The protein expression was mutually exclusive and no duplicate cases were observed. A log-rank test showed that MYC family-positive status was significantly associated with shorter overall survival (OS) (p = 0.003) and recurrence-free survival (RFS) (p = 0.039). According to Cox multivariate analysis, MYC family-positive status had a significant effect on shorter OS (hazard ratio [HR] = 2.217, 95% confidence interval [CI] 1.179-4.169, p = 0.014) and RFS (HR = 1.802, 95% CI 1.014-3.202, p = 0.045). In patients with pathological stage I, MYC family-positive status also showed significantly poor OS (HR = 2.847, 95% CI 1.236-6.557, p = 0.014) and RFS (HR = 2.088, 95% CI 1.006-4.332, p = 0.048) in the multivariate analysis. CONCLUSIONS: MYC family protein expression could be an independent unfavorable prognostic factor in patients with surgically resected HGNEC.

Video-Assisted Thoracoscopic Surgery Using Extracorporeal Membrane Oxygenation for Intractable Pneumothorax.

Intractable pneumothorax with poor lung function that has received multiple conservative treatments may occur. Case 1 was a 70-year-old woman with aspergilloma who was admitted for pneumothorax. Case 2 was a 68-year-old man with acute exacerbation of interstitial pneumonia who developed pneumothorax. In both cases, multiple conservative therapies were administered, but the leak continued; thus, operations using veno-venous extracorporeal membrane oxygenation (ECMO) were planned. By video-assisted thoracoscopic surgery (VATS), we obtained the optimal surgical field by lung collapse. We removed many blood clots that were used for pleurodesis, ligated the bulla in case 1, and covered the leak point with strengthening agents in case 2. For cases of intractable pneumothorax, lung collapse by ECMO is advantageous because we can check details and leak points even in blood clots or in poor condition of the lung, and we can maneuver the lung in poor condition with a clear surgical field.

The impact of COVID-19 on thoracic surgical procedures in Japan: Analysis of data from the National Clinical Database.

OBJECTIVE: The COVID-19 pandemic has far-reaching collateral health impacts on the ongoing delivery of surgical care worldwide. The current study was designed to analyze the impact of the COVID-19 pandemic on the number of surgeries of general thoracic surgery in Japan. METHODS: Changes in the number of surgeries for total and three representative tumors were analyzed using the National Clinical Database data with reference to the pandemic infection rate and lung cancer screening. RESULTS: In 2020, the number of surgeries in total and for primary lung cancer and mediastinal lung tumor decreased by 4.9, 5.1, and 5.0 %, respectively. Considering the five-year trend towards a 5 % annual increase, there was a potential 10 % decrease in the number of primary lung cancer surgeries. The number of primary lung cancer surgeries bottomed in July 2020 but recovered towards the end of the year. In contrast, the number of metastatic lung tumor surgeries in 2020 increased by 3.2 %, following a similar trend observed over the previous five years. The number of lung cancer screening examinees decreased markedly with the lowest number in May. Our findings indicate that surgical triage had a limited impact on the decrease in primary lung cancer surgeries during the pandemic; rather, the decrease in lung cancer screening, which was a few months preceding, is most likely responsible. CONCLUSIONS: The decrease in primary lung cancer was mainly caused by the decrease in lung cancer screening, indicating that continuing screening is vital even during a pandemic.

Prognostic impact of surgical treatment for high-grade neuroendocrine carcinoma of the lung: a multi-institutional retrospective study.

Background: High-grade neuroendocrine carcinoma (HGNEC) of the lung, which includes small cell lung cancer (SCLC) and large cell neuroendocrine carcinoma (LCNEC), is an aggressive form of lung cancer. Although lobectomy followed by adjuvant chemotherapy is regarded as the standard therapy for this disease, it would be an uphill struggle for HGNEC patients to receive that multidisciplinary therapy perfectly. This study aimed to examine recurrence and survival outcomes in surgically treated patients with HGNEC of the lung. Methods: The medical records of 104 HGNEC patients who underwent surgical treatment in five institutions were retrospectively analyzed. Standard treatment (ST) was defined as lobectomy, bilobectomy, or pneumonectomy with mediastinal lymph node dissection followed by adjuvant platinum-doublet chemotherapy with more than two cycles. Results: Patients in the ST group (n=31; 30%) were younger and had fewer respiratory complications than those in the non-standard treatment (NST) group (n=73; 70%). A significantly higher proportion of patients in the NST group developed ipsilateral lymph node recurrence (21% vs. 3%; P=0.035) and ipsilateral or contralateral lung recurrence (15% vs. 0%; P=0.031). Five-year overall survival (OS) was 64.2% in the ST group and 38.3% in the NST group (P=0.038). NST was independently associated with worse OS in multivariate analysis (hazard ratio, 2.044; 95% confidence interval, 1.016-4.113; P=0.045). Conclusions: Surgically treated HGNEC patients who received ST had a more favorable outcome than those who received NST. Patients who receive NST may require additional treatment.

High mRNA expression of POU2F3 in small cell lung cancer cell lines predicts the effect of lurbinectedin.

BACKGROUND: Small cell lung cancer (SCLC) is a progressive disease with a poor prognosis. Recently, a method to classify SCLC by the expression status of four transcription factors, ASCL1, NEUROD1, POU2F3, and YAP1, was proposed. Here, we investigated the potential relationships between expression of these four transcription factors and the effect of lurbinectedin. METHODS: mRNA and protein expression of ASCL1, NEUROD1, POU2F3, and YAP1 were quantified in eight SCLC cell lines and analyzed for potential correlations with drug sensitivity. In addition, ASCL1, NEUROD1, POU2F3, and YAP1 expression were evaluated in 105 resected cases of high-grade neuroendocrine carcinoma of the lung, including 59 resected cases of SCLC. RESULTS: Based on the results of qRT-PCR and western blot analyses, the eight SCLC cell lines examined were classified into NEUROD1, POU2F3, and YAP1 subtypes, as well as five ASCL1 subtypes. There were no correlations between cell line subtype classification and drug sensitivity to cisplatin, etoposide, or lurbinectedin. Next, we compared relative mRNA expression levels of each transcription factor with drug sensitivity and found that the higher the mRNA expression level of POU2F3, the lower the IC50 of lurbinectedin. Evaluation of resected SCLC tissue revealed that the composition of subtypes defined by the relative dominance of ASCL1, NEUROD1, POU2F3, and YAP1 was as follows: 61% ASCL1, 15% NEUROD1, 14% POU2F3, 5% YAP1, and 5% all-negative. CONCLUSION: In our experiments, high mRNA expression of POU2F3 in SCLC cell lines correlated with the effect of lurbinectedin.

The C-reactive protein to albumin ratio is a prognostic factor for stage I non-small cell lung cancer in elderly patients: JACS1303.

PURPOSE: To establish the prognostic significance of C-reactive protein (CRP) and albumin in octogenarians with non-small cell lung cancer (NSCLC) based on the study of the Japanese Association for Chest Surgery (JACS 1303). METHODS: A total of 618 octogenarians with pathological stage I NSCLC, who underwent pulmonary resection, were included in the analysis. We conducted multivariable Cox regression analysis to evaluate the CRP to albumin ratio (CAR) as a potential prognostic factor. Other clinicopathological factors were also evaluated. RESULTS: The median age was 82 years. Operations included lobectomy (n = 388; 62.8%) segmentectomy (n = 95; 15%), and wedge resection (n = 135; 22%). Pathological stage IA was diagnosed in 380 (61.5%) patients. The 3-year (OS) and cancer-specific survival (CS) rates were 86.7% and 94.6%, respectively. OS was significantly higher for patients with low CAR (< 0.106) than for those with high CAR (≥ 0.106) (hazard ratio = 3.13, 95% confidence interval: 1.99-4.93, p < 0.0001). Univariate analysis identified sex, poor performance status, smoking status, comorbidity, solid tumor, histology, high Glasgow prognostic scale, and high CAR as significant prognostic factors. Multivariate analysis identified only the CAR as a significant prognostic factor for both OS and CS. CONCLUSIONS: Our analysis of the nationwide data demonstrated that the CAR is a useful prognostic factor for elderly patients with stage I NSCLC.

Gene expression profiling using targeted RNA-sequencing to elucidate the progression from histologically normal lung tissues to non-invasive lesions in invasive lung adenocarcinoma.

Lung adenocarcinoma (LUAD) shows heterogeneous morphological features and the stepwise progression from adenocarcinoma in situ to minimally invasive adenocarcinoma to invasive LUAD. Although multiple genetic alterations have been linked to the progression, the differences between the gene expression profiles of non-invasive lesions (non-ILs) and adjacent histologically normal lung (aNL) tissues within invasive LUAD have not been investigated. Herein, we analyzed differentially expressed genes (DEGs) specific to early-stage carcinogenesis in LUAD. Invasive LUAD tissue samples containing both non-ILs and aNL tissues were obtained from seven patients with pathological stage I LUAD, and each component was subjected to microdissection. Gene expression profiles of each component were determined using targeted RNA-sequencing. In total, 2536 DEGs, including 863 upregulated and 1673 downregulated genes, were identified in non-ILs. In non-ILs, the expression of SLC44A5, a choline transporter-like protein-coding gene, was significantly upregulated, and that of TMEM100, a gene encoding a transmembrane protein, was significantly downregulated. Reportedly, SLC44A5 plays an important role in the development and progression of hepatocellular carcinoma, whereas TMEM100 functions as a tumor suppressor in non-small cell lung cancer. Gene set enrichment analysis showed that DEGs in non-ILs were negatively enriched in cell death and immune response. Immunohistochemical analysis revealed that increased SLC44A5 expression and decreased TMEM100 expression were maintained in ILs. A protein-protein interaction (PPI) network analysis identified several upregulated and downregulated hub genes with high degrees in non-ILs. In conclusion, several new DEGs and key PPI network hub genes were identified in non-ILs, contributing to understanding of early-stage carcinogenesis in LUAD.

Prognostic Impact of Mediastinal Lymph Node Dissection in Octogenarians With Lung Cancer: JACS1303.

INTRODUCTION: The prognostic significance of mediastinal lymph node dissection (MLND) in elderly patients with non-small cell lung cancer (NSCLC) remains unclear. This post hoc analysis of a nationwide multicenter cohort study (JACS1303) evaluated the prognostic significance of MLND in octogenarians with NSCLC. MATERIALS AND METHODS: We included 622 octogenarians with NSCLC who underwent lobectomy. The median follow-up duration was 41.1 months. We compared survival and perioperative outcomes between patients who did and did not undergo MLND. RESULTS: In total, 414 (67%) patients underwent MLND (ND2 group), whereas 208 (33%) did not undergo MLND (ND0-1 group). The disease stage was more advanced in the ND2 group than in the ND0-1 group. Disease-free survival was slightly greater in the ND0-1 group with marginal significance (P= .079). In the matched cohort (N = 228), which mainly consisted of patients with clinical stage I disease (96%), there was no significant difference between the 2 groups regarding overall and disease-free survival (P= .908 and P = .916, respectively). Operative time and blood loss were significantly lower in the ND0-1 group than in the ND2 group in the entire cohort (P< .001 and P = .050, respectively) and in the matched cohort (P = .003 and P= .046, respectively). CONCLUSION: Based on a nationwide prospective database, we found limited prognostic impact of MLND, suggesting that MLND can be omitted for octogenarians with early-stage NSCLC.

Clinical Significance of Serglycin Expression in Human Breast Cancer Patients.

BACKGROUND/AIM: Serglycin plays a crucial role in the aggressiveness of several types of malignancies, including breast cancer. In this study, we aimed to investigate the prognostic impact of serglycin expression in breast cancer patients, which has not been previously reported. PATIENTS AND METHODS: Immunohistochemical analyses were performed on 348 resected specimens of invasive carcinomas, using antibodies against serglycin. RESULTS: Low serglycin expression was observed in 23% of specimens (80/348) and significantly correlated with high histological grade (p=0.001) and negative ER (p=0.013). The log-rank test showed that low serglycin expression correlated with shorter distant metastasis-free survival (DMFS) (p=0.016) and disease-specific survival (DSS) (p=0.037) in node-positive breast cancer patients. Cox's multivariate analysis revealed that low serglycin expression was an independent factor for shorter DMFS (p=0.017) and DSS (p=0.020) in node-positive breast cancer patients. CONCLUSION: Low serglycin expression is an independent predictor of unfavorable prognosis in node-positive breast cancer patients.

A rare case of combined thymoma and a multilocular thymic cyst discovered due to chest pain.

BACKGROUND: A thymoma with chest pain and multilocular thymic cysts (MTCs) is very rare. CASE PRESENTATION: A 49-year-old man presented to another hospital complaining of an anterior chest pain. Chest computed tomography (CT) showed an anterior mediastinal tumor 60 × 30 × 55 mm in size. The boundary with the pericardium or left brachiocephalic vein seemed to be partially unclear while enhanced by the contrast medium, and so the tumor could have invaded them. No definitive diagnosis of myasthenia gravis was made although the serum anti-acetylcholine receptor antibody count was high. We performed an extended thymectomy with combined partial resection of left brachiocephalic vein, left upper lobe, and left phrenic nerve. He was discharged with no chest pain and no complications post-surgery. The tumor was pathologically type B2 thymoma with hemorrhage necrosis and MTCs, and we diagnosed Masaoka stage II because of no histological infiltration to the organs. CONCLUSIONS: We speculated that hemorrhagic necrosis due to infarction in tumor caused the inflammation to spread to the surrounding organs, which was related to the chest pain and the development of MTCs.

Comparison between robot-assisted thoracoscopic surgery and video-assisted thoracoscopic surgery for mediastinal and hilar lymph node dissection in lung cancer surgery.

OBJECTIVES: Lymph node dissection (LND) with robot-assisted thoracoscopic surgery (RATS) in lung cancer surgery has not been fully evaluated. The aim of this study was to compare LND surgical results between video-assisted thoracoscopic surgery (VATS) and RATS. METHODS: We retrospectively compared perioperative parameters, including the incidence of LND-associated complications (chylothorax, recurrent and/or phrenic nerve paralysis and bronchopleural fistula), lymph node (LN) counts and postoperative locoregional recurrence, among 390 patients with primary lung cancer who underwent lobectomy and mediastinal LND by RATS (n = 104) or VATS (n = 286) at our institution. RESULTS: The median total dissected LN numbers significantly differed between the RATS and the VATS groups (RATS: 18, VATS: 15; P < 0.001). They also significantly differed in right upper zone and hilar (#2R + #4R + #10L) (RATS: 12, VATS: 10; P = 0.002), left lower paratracheal and hilar (#4L + #10L) (RATS: 4, VATS: 3; P = 0.019), aortopulmonary zone (#5 + #6) (RATS: 3, VATS: 2; P = 0.001) and interlobar and lobar (#11 + #12) LNs (RATS: 7, VATS: 6; P = 0.041). The groups did not significantly differ in overall nodal upstaging (P = 0.64), total blood loss (P = 0.69) or incidence of LND-associated complications (P = 0.77). CONCLUSIONS: In this comparison, it was suggested that more LNs could be dissected using RATS than VATS, especially in bilateral superior mediastinum and hilar regions. Accumulation of more cases and longer observation periods are needed to verify whether RATS can provide the acceptable quality of LND and local control of lung cancer.