Cytological features of stromal spindle cells and their prognostic significance in lung adenocarcinoma.

INTRODUCTION: Cancer-associated fibroblasts (CAFs) in the tumour microenvironment play a key role in tumour development, proliferation, invasion, and metastasis. The cytological features of spindle cells including CAFs-defined as stromal spindle cells (SSCs) adjacent to cancer cells-are frequently encountered in pulmonary adenocarcinomas. This study aimed to investigate the association between the presence of SSCs in cytological specimens and the clinicopathological features. METHODS: We evaluated 211 patients with pulmonary adenocarcinoma who underwent surgical resection. All participants had cytological specimens corresponding to the histological specimens available for review. RESULTS: Of the 211 cases examined, 89 were SSC-positive (SSC+ ) and 122 were SSC-negative (SSC- ). SSC+ cases were more frequently associated with higher pathological stage (P < 0.001), lymph node metastasis (P = 0.002), anaplastic lymphoma kinase (ALK) gene rearrangement (P = 0.04), high tumour grade (P < 0.001), solid and micropapillary predominant pattern (P = 0.02), and lymphatic vessel (P = 0.003), blood vessel (P < 0.001), and pleural invasion (P = 0.03) as compared to SSC- cases. Patients with SSC+ adenocarcinoma had a significantly shorter recurrence-free survival than those with SSC- adenocarcinoma (P = 0.009). Cytologically, necrotic background (P = 0.002), mucinous cancer cells (P = 0.02), pleomorphic cells (P < 0.001), and mutual cell inclusions (P = 0.01) were observed more frequently in SSC+ adenocarcinomas. CONCLUSIONS: The presence of SSCs could be an important cytological feature for predicting poor prognosis in lung adenocarcinomas.

[Traumatic Lung Injury].

Thoracic injuries are significant causes of morbidity and mortality in trauma patients. Traumatic pulmonary contusion and/or laceration are often observed in patients with chest trauma, explosion injuries or a shock wave associated with penetrating trauma. A pulmonary contusion is an injury to the lung parenchyma without actual structural damage. As a result of damage to alveoli and capillaries, it results in leakage of blood and other interstitial fluids across the alveolar-capillary membrane into lung tissue and alveolar space. Since oxygenated air can not enter into fluid-filled alveoli, hypoventilation and decreased perfusion by reflux vasoconstriction result in hypoxemia and hypercapnia. Pulmonary laceration is a lung injury with disruption of the architecture of the lung, while pulmonary contusion does not. There is almost always concurrent pulmonary contusion, and pneumothorax, hemothorax, or hemopneumothorax. In addition, pulmonary laceration can be a cause of forming a cyst or hematoma, which usually disappears over a period of weeks or months. However, pneumatocele can occur in some cases when lacerations are enlarged with air-filled cavity. It is important for thoracic surgeons to understand pathophysiology of traumatic lung injury, and to know the diagnosis and treatment.

The Utility of Indigo Carmine and Lipiodol Mixture for Preoperative Pulmonary Nodule Localization before Video-Assisted Thoracic Surgery.

PURPOSE: To evaluate the safety and efficacy of a mixture of indigo carmine and lipiodol (MIL) as a marker of pulmonary nodule before video-assisted thoracic surgery (VATS). MATERIALS AND METHODS: One hundred sixty-eight sessions of pulmonary marking were performed using MIL before VATS for 184 nodules (mean size, 1.2 ± 0.6 cm; range, 0.3-3.6 cm) on 157 patients (83 men and 74 women; median age, 66 years). The mean distance between the lung surface and the nodule was 0.8 ± 0.7 cm (range, 0-3.9 cm). MIL was injected near the nodule using a 23-gauge needle. Mean number of 1.2 ± 0.4 (range, 1-3) punctures were performed in a session for the target nodules, with mean number of 1.1 ± 0.3 (range, 1-3). Successful targeting, localization, and VATS were defined as achievement of lipiodol accumulation at the target site on computed tomography, detection of the nodule in the operative field by fluoroscopy or visualization of dye pigmentation, and complete resection of the target nodule with sufficient margin, respectively. RESULTS: The successful targeting rate was 100%, and the successful localization rate was 99.5%, with dye pigmentation for 160 nodules (87.0%) and intraoperative fluoroscopy for 23 nodules (12.5%). Successful VATS was achieved for 181 nodules (98.4%). Two nodules (1.1%) were not resectable, and surgical margin was positive in 1 nodule (0.5%). Complications requiring interventions occurred in 5 sessions (3.0%) and included pneumothorax with chest tube placement (n = 3) and aspiration (n = 2). No complication related to the injected MIL occurred. CONCLUSIONS: MIL was safe and useful for preoperative pulmonary nodule marking.

Salvage surgery for small cell lung cancer after chemoradiotherapy.

There are few reports on the use of salvage surgery for small cell lung cancer (SCLC). Five patients who underwent resection of post-chemoradiotherapy residual lesion/local reprogression of SCLC between 2005 and 2017 were included in the study. We retrospectively reviewed their surgical outcomes and prognosis to assess the feasibility and potential efficacy of salvage surgery. Indications for salvage surgery were local reprogression (four patients) and residual lesion (one patient) with ycN0 disease. Complete pathological resection was achieved in four patients; however, malignant pleural effusion was diagnosed in one patient after the surgery. Morbidity and mortality rates were 0%. Estimated 5-year survival rate was 67%. Recurrence and death after surgery occurred only in the patient with malignant pleural effusion. We demonstrate the feasibility of salvage surgery in SCLC. In carefully-selected patients, especially those without lymph node involvement, salvage surgery may provide effective local control and favorable survival outcomes.

Novel development of Spectra-A using indocyanine green for segmental boundary visibility in thoracoscopic segmentectomy.

BACKGROUND: Our previous report suggested that fluorescence thoracoscopic anatomical segmentectomy (TAS) using intravenous (IV) indocyanine green (ICG) injection is safe, feasible, and efficacious for identifying segmental boundaries. However, contrast visualization in the conventional indocyanine green mode (CIM) remains relatively obscure in smoking-related comorbidities. Our aim was to evaluate the safety and efficacy of recently released Spectra-A with CIM by simultaneous observation. MATERIALS AND METHODS: We postoperatively analyzed captive imaging using histogram counts in 29 patients who underwent TAS and previously reported that Δ indicates the index of visualization obtained by subtraction from its representative illuminated signal quantities of maximum pixels so that light-shade, intensity-removed image signals are obtained. RESULTS: Sixteen (55.2%) patients were male, and 13 (44.8%) were female. Segmental boundaries were successfully visualized in all patients (100%). The histogram count widths in dim and bright segments with CIM were 13.3 ± 3.8 and 52.5 ± 12.2, and those with Spectra-A were 19.4 ± 6.1 and 118.1 ± 37.4, respectively. The mean value was 4.3-fold higher for ΔSpa-A (61.4 ± 33.2) than for ΔCIM (14.2 ± 8.5) (P < 0.01). In 14 (48.3%) patients, the segmental boundary could not be clearly visualized using CIM but was explicitly identified using Spectra-A. CONCLUSIONS: Spectra-A is a safe and promising noninvasive alternative like CIM, and more effective because of overcoming the limitation of CIM, but its use should be studied further to determine its usefulness in identifying segmental boundaries.

Unique prevalence of oncogenic genetic alterations in young patients with lung adenocarcinoma.

BACKGROUND: Lung adenocarcinoma in the young is a rare entity, and the oncogenic genetic alterations (GAs) and clinical characteristics associated with this disease are poorly understood. Conversely, it has been demonstrated that young age at diagnosis defines unique biology in other cancers. For this report, the effects of young age on lung adenocarcinoma are reported. METHODS: The authors retrospectively screened 1746 consecutive patients who were diagnosed with stage I through IV adenocarcinoma between 2009 and 2015 and identified 81 who were aged 40 years or younger at diagnosis. The clinical and genetic characteristics of this younger population were analyzed. RESULTS: Of the 81 younger patients identified, 36 (44%) were men, 36 (44%) were never smokers, and the median age was 36 years (range, 26-40 years). Thirty-three patients (41%) harbored anaplastic lymphoma kinase (ALK) translocations, 24 (30%) had epidermal growth factor receptor (EGFR) mutations, and 2 (2%) had v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations. Rare oncogenic GAs also were studied in patients who had wild-type ALK/EGFR/KRAS adenocarcinoma, including 4 patients with HER2 mutations, 2 with Ret proto-oncogene (RET) translocations, and 2 with ROS proto-oncogene 1 receptor tyrosine kinase (ROS1) translocations. Notably, oncogenic GAs (P < .001), ALK (P < .001) and ROS1 (P = .033) translocations, and HER2 mutations (P < .001) were associated with young age, and a similar trend was observed for RET translocations (P = .108). Younger patients who had adenocarcinoma without GAs had a significantly worse prognosis compared with older patients without GAs (overall survival, 8.9 vs 16.4 months; P < .001) and patients with GAs (24.9 months; P < .001). CONCLUSIONS: Younger patients with adenocarcinoma have a distinctly unique prevalence of oncogenic GAs. Comprehensive oncogenic GA screening is especially recommended for personalized medicine strategies in this population. Cancer 2017;123:1731-1740. © 2017 American Cancer Society.

Impact of the oncogenic status on the mode of recurrence in resected non-small cell lung cancer.

OBJECTIVE: Surgical resection is employed in patients with resectable non-small cell lung cancer. Despite complete resection, recurrence is sometimes observed. Oncogenic mutations promote initiation and progression of lung cancer, and mutation status predicts treatment outcome of advanced non-small cell lung cancer; however, their impact on the recurrence patterns remains poorly understood. METHODS: We retrospectively studied 401 patients showing recurrence after complete resection of non-small cell lung cancer. Clinicopathological factors were reviewed for time to recurrence, and recurrence patterns were compared according to oncogenic status and examined according to EGFR mutational subtype. RESULTS: Among 401 patients, 185 with EGFR mutation, 46 with KRAS mutation, 15 with ALK rearrangement and 155 with triple-negative mutation were identified. Multivariate analysis following univariate analyses showed that younger age, well-moderately-differentiated histology, earlier pathologic stage and presence of EGFR or ALK mutation were favorable prognostic factors for time to recurrence. Locoregional recurrence was observed in 53.3% of ALK-positive patients, being significantly common in these patients than in EGFR- and KRAS-positive patients. EGFR-positive patients mostly experienced pleural recurrence, the incidence of which was significantly higher in triple-negative mutation patients. Adrenal recurrence was observed in 7.2% of triple-negative mutation patients, but it was rarely identified in EGFR-positive patients. Among EGFR-positive patients, the incidence of brain metastases was significantly higher in L858R cohort than in Del Ex19 cohort. CONCLUSIONS: In resected non-small cell lung cancer, younger age, well-moderately-differentiated histology, earlier pathologic stage and presence of EGFR or ALK mutation were favorable factors for TTR, and distinct recurrence patterns were revealed according to oncogenic mutation status and mutational EGFR subtype. Our results may provide suggestions for developing a strategy for follow-up and adjuvant therapies after resection.

[Castleman's Disease of the Chest Wall Successfully Resected by Thoracoscopic Surgery；Report of a Case].

A 61-year-old woman without a significant past medical history was pointed out the abnormal shadow on the annual medical checkup. Chest computed tomography (CT) revealed a well-defined paravertebral chest wall tumor of 20 mm in maxmum size. Furthermore, diffusion weighted image on magnetic resonance imaging (MRI) showed high intensity, and standardized uptake value (SUV) max on positron emission tomography/computed tomography (PET/CT) was 13.4. Schwanoma, solitary fibrous tumor (SFT) or malignant lymphoma was suggested. Complete resection was performed with thoracoscopic surgery. The histological diagnosis was Castleman's disease with hyalineized type.

Resection of a ruptured mature cystic teratoma diagnosed two years after the onset of perforation.

Perforated cystic teratomas are rare. Our patient was a 16-year-old female who presented with severe chest pain two years ago. A right-sided pleural effusion was accidentally detected by chest radiography performed at her school. Computed tomography revealed a high density area with multiple small, thickened, lobulated lesions and a low density area with pleural effusion adjacent to a thinned wall. Pathognomonic inhomogeneous computed tomography findings led to an accurate diagnosis of a mature teratoma that had ruptured long before presentation. Thoracoscopic resection was performed, and the final histological diagnosis was a mature teratoma with partial rupture.

A Comparison of the Efficacies of OK-432 and Talc Slurry for Pleurodesis in Patients with Prolonged Air Leak after Pulmonary Resection.

PURPOSE: A prolonged air leak (PAL) is one of the common postoperative complications of pulmonary resection. The aim of this study was to evaluate the efficacy and safety of pleurodesis with sterile talc or OK-432 for postoperative air leak. METHODS: Patients with postoperative air leak who received chemical pleurodesis using sterile talc or OK-432 were retrospectively identified from medical records data. For pleurodesis with either agent, prior assessment and approval by the hospital safety department were carried out for each case, in addition to individual consent. RESULTS: Between February 2016 and June 2022, 39 patients had PALs and underwent chemical pleurodesis. Among them, 24 patients received pleurodesis with talc (Talc group) and 15 with OK-432 (OK-432 group). The leak resolved after less than two pleurodesis treatments in 22 patients (91.7%) in the Talc group compared with 14 patients (93.3%) in the OK-432 group. Pleurodesis significantly increased white blood cell counts, C-reactive protein concentration, and body temperature in the OK-432 group compared with that in the Talc group (p <0.001, p = 0.003, and p <0.001, respectively). CONCLUSIONS: Pleurodesis with talc may be an effective treatment option for postoperative air leak. Our findings suggest that talc was as effective as OK-432 and resulted in a milder systemic inflammatory response.

Arterial Embolization and Cone-Beam Computed Tomography-Guided Lung Resection for Anomalous Systemic Arterial Blood Supply to Normal Lung: Two Case Reports.

Systemic arterial blood supply to a normal lung is a rare anatomical abnormality. Surgery is usually indicated because this abnormality leads to pulmonary hypertension. Herein, we report our experience and ideas for safe vessel dissection. Case 1 was a woman in her 50s. We performed a left lower lobectomy following percutaneous coil embolization. The aberrant artery with emboli was confirmed intraoperatively by cone-beam computed tomography (CBCT) to safely dissect under thoracoscopic surgery (TS). Case 2 was a man in his 40s. Following percutaneous endovascular plug occlusion, we performed a left partial resection using indocyanine green fluorescence navigation. Intraoperatively, CBCT imaging demonstrated the aberrant artery and exact position of the emboli. This combination technique of interventional radiology and TS with CBCT imaging was considered safe and more secure for the treatment of anomalous systemic arterial blood supply to a normal lung.

Successful resection of a primary angiosarcoma of the azygos vein: A case report.

A 63-year-old woman was admitted to our department for the investigation of superior vena cava (SVC) syndrome. Computed tomography revealed an azygos tumor extending into the SVC. Video-assisted thoracic surgery (VATS) was performed to remove the distal end of the azygos vein in the left lateral position, followed by complete resection of the entire tumor under median sternotomy in the supine position. The histological diagnosis was a primary angiosarcoma of the azygos vein. The patient was discharged without any complications and is now alive and tumor-free 24 months after surgery. In addition, contrast-enhanced computed tomography revealed no graft occlusion in the two reconstructed brachiocephalic veins. Thoracoscopic surgery in the lateral position is useful for safe and reliable complete resection of a tumor arising from the azygos vein.

Perioperative Evaluation of the Physical Quality of Life of Patients with Non-Small Cell Lung Cancer: A Prospective Study.

Surgery is the most effective treatment for early-stage lung cancer; however, it poses a higher physical burden than other treatment options. Therefore, understanding the perioperative course of patients is important. Using the Short Form Health Survey 36, we prospectively measured the physical quality of life of patients who underwent anatomical pulmonary resection for non-small cell lung cancer at Shonan Kamakura General Hospital, Kanagawa, Japan (n = 87). In the preoperative setting, patients who had lower performance status and lived alone had significantly worse physical quality of life scores on multivariate analysis (regression coefficient (95% confidence interval), -9.37 (-13.43--5.32) and -10.22 (-13.74--7.40), respectively, p < 0.0001 for both). At 6 months postoperatively, patients who stopped smoking within 1 year preoperatively (stopped smoking within 1 year vs. remote or never smokers, 41.0 ± 10.5 vs. 48.6 ± 7.2, p = 0.002), had lower performance status (0 vs. 1-2, 49.3 ± 6.6 vs. 38.6 ± 9.6, p < 0.0001), lived alone (living alone vs. living with somebody, 41.6 ± 9.7 vs. 48.1 ± 7.9, p = 0.021), and had higher comorbid burden (Charlson comorbidity index <3 vs. ≥3, 48.2 ± 6.9 vs. 39.1 ± 14.7, p = 0.003) had significantly worse physical quality of life scores on univariate analysis. More recent smoking (regression coefficient (95% confidence interval), -4.90 (-8.78-1.0), p = 0.014), lower performance status (8.90 (5.10-12.70), p < 0.0001), living alone (5.76 (1.39-10.13), p = 0.01), and higher comorbid burden (-6.94 (-11.78--2.10), p = 0.006) were significant independent predictors of worse postoperative physical quality of life on multivariate analysis. Therefore, patients with these conditions might need additional support to maintain their physical condition after anatomical lung cancer surgery.

Allelotypes of lung adenocarcinomas featuring ALK fusion demonstrate fewer onco- and suppressor gene changes.

BACKGROUND: A subset of lung adenocarcinomas harboring an EML4-ALK fusion gene resulting in dominant oncogenic activity has emerged as a target for specific therapy. EML4-ALK fusion confers a characteristic histology and is detected more frequently in never or light smokers and younger patients. METHODS: To gain insights into etiology and carcinogenic mechanisms we conducted analyses to compare allelotypes of 35 ALK fusion-positive and 95 -negative tumours using single nucleotide polymorphism (SNP) arrays and especially designed software which enabled precise global genomic profiling. RESULTS: Overall aberration numbers (gains + losses) of chromosomal alterations were 8.42 and 9.56 in tumours with and without ALK fusion, respectively, the difference not being statistically significant, although patterns of gain and loss were distinct. Interestingly, among selected genomic regions, oncogene-related examples such as 1p34.3(MYCL1), 7q11.2(EGFR), 7p21.1, 8q24.21(MYC), 16p13.3, 17q12(ERBB2) and 17q25.1 showed significantly less gain. Also, changes in tumour suppressor gene-related regions, such as 9p21.3 (CDKN2A) 9p23-24.1 (PTPRD), 13q14.2 (RB1), were significantly fewer in tumours with ALK fusion. CONCLUSION: Global genomic comparison with SNP arrays showed tumours with ALK fusion to have fewer alterations in oncogenes and suppressor genes despite a similar overall aberration frequency, suggesting very strong oncogenic potency of ALK activation by gene fusion.

Solitary pulmonary capillary hemangioma mimicking a preinvasive malignant lesion in an asymptomatic middle-aged female patient.

Pulmonary capillary hemangiomatosis (PCH) is a rare disease characterized by a proliferation of capillaries in the alveolar septa, bronchial and venous walls, pleura, and regional lymph nodes. However, the etiology of the disease remains unknown due to its rarity. Therefore, we present a case of a solitary PCH lesion without symptoms in a 38-year-old female patient. According to computed tomography, she was diagnosed with lung carcinoma, indicated by a tiny nodule with ground-glass opacity detected in her right upper lung. However, no other lesions were detected on systemic examination. Consequently, partial lung resection was conducted, since the lesion was suspected of lung adenocarcinoma. Pathologic results showed that the thick alveolar septa were caused by capillary growth without cellular atypia and hardly any infiltration of inflammatory cells. Finally, we diagnosed the pulmonary lesion as PCH, although solitary PCH has previously been reported in a few case reports. Therefore, further case studies are essential to clarify the causes of PCH.

Optimal Chest Drainage Method After Anatomic Lung Resection: A Prospective Observational Study.

BACKGROUND: Several methods for chest drainage after pulmonary resection of malignant lung tumors exist, but consensus on the ideal method has not been reached. METHODS: We conducted a multicenter prospective observational study. We enrolled 2200 patients who underwent lung resection for lung tumors. Of the 1470 patients who underwent anatomic resection, 347 showed air leak on the morning of postoperative day 1. They were assigned to 3 groups according to the chest drainage method on postoperative day 1. RESULTS: Of 347 patients with postoperative air leaks, 107 (30.8%), 179 (51.6%), and 61 (17.6%) were assigned to water seal, continuous suction, and digital drainage, respectively. The median postoperative air leak duration was significantly longer with digital drainage (4.0 days) than with either water seal (2.5 days) or continuous suction (3.0 days; P = .009). Chest tubes were required for significantly more days on average with digital drainage (6.0 days) than with water seal (4.0 days) or continuous suction (4.0 days; P = .003). Prolongation of air leak duration was significantly more likely to occur in patients with body mass index <18.5 kg/m2 (hazard ratio [HR], 1.6; 95% CI, 1.1-2.3), moderate or severe air leak on postoperative day 1 (HR, 2.0; 95% CI, 1.5-2.6), or digital drainage (HR, 1.4; 95% CI, 1.01-1.9). CONCLUSIONS: Water seal was associated with significantly shorter duration of postoperative air leak and chest drainage compared with continuous suction and digital drainage.

Survival after Lung Metastasectomy from Esophageal Cancer: Results from a Multi-Institutional Database.

To clarify the clinical impact and to identify prognostic predictors of surgical intervention for pulmonary metastasis from esophageal cancer, a registry database analysis was performed. From January 2000 to March 2020, patients who underwent resection of pulmonary metastases from primary esophageal cancer at 18 institutions were registered in a database developed by the Metastatic Lung Tumor Study Group of Japan. An amount of 109 cases were reviewed and examined for the prognostic factors for pulmonary metastasectomy of metastases from esophageal cancer. As a result, five-year overall survival after pulmonary metastasectomy was 34.4% and five-year disease-free survival was 22.1%. The multivariate analysis for overall survival revealed that initial recurrence site, maximum tumor size, and duration from primary tumor treatment to lung surgery were selected as the significant prognostic factors (p = 0.043, p = 0.048, and p = 0.037, respectively). In addition, from the results of the multivariate analysis for disease free survival, number of lung metastases, initial recurrence site, duration from primary tumor treatment to lung surgery, and preoperative chemotherapy for lung metastasis were selected as the significant prognostic factors (p = 0.037, p = 0.008, p = 0.010, and p = 0.020, respectively). In conclusion, eligible patients with pulmonary metastasis from esophageal cancer selected based on the identified prognostic predictors would be good candidates for pulmonary metastasectomy.

Clinical impact of intraoperative detection of carcinoembryonic antigen mRNA in pleural lavage specimens from nonsmall cell lung cancer patients.

BACKGROUND: The prospective trial of intraoperative detection of carcinoembryonic antigen mRNA (mCEA) in pleural lavage in patients undergoing resection for nonsmall cell lung cancers (NSCLCs) was undertaken to analyze clinical applicability. METHODS: From January 2006 to August 2008, cytology and mCEA analysis with pleural lavage were performed for 383 patients undergoing resection of NSCLCs. The pleural cavity was washed with 100 mL of physiological saline, and recovered lavage fluid was divided into two portions, one for pleural lavage cytology and the other for determination of mCEA expression by the transcription reverse transcription concerted reaction method. RESULTS: One hundred and nineteen (31%) cases were mCEA-positive. Positive mCEA results were observed frequently for adenocarcinoma patients and were recognized as a suggestive prognostic factor by stepwise regression analyses (p = 0.0472). The overall 4-year survival rate was 56% in the mCEA-positive group and 81% in the negative cases (p = 0.003). Of 71 cases suffering recurrence, it occurred frequently in mCEA-positive group (p = 0.035). CONCLUSION: Intraoperative mCEA analysis may be a reliable indicator for assessing short-term prognosis and likelihood of early recurrence.

[Indication and results of thoracoscopic segmentectomy for small peripheral lung cancer].

Since 2008, 46 patients have undergone thoracoscopic segmentectomy without mini-thoracotomy for almost pure ground-glass opacity (GGO) lesion by thin-section computed tomography (CT) finding which was difficult to be performed wedge resection. No patient was converted to both thoracotomy and lobectomy. The operation time ranged from 75 to 240 min (mean, 161 min), and blood loss ranged from 1 to 110 g( mean, 25 g). We used stapler in 29 patients and electrocautery in 17 patients to deviate inter segmental plane. Postoperative complications were seen in 6 patients (13%), major complication was air leakage in 6 patients. There was no in-hospital mortality. Only 1 patient had bone metastasis on 11 months after operation. Thoracoscopic segmentectomy considered to be a safe and feasible procedure for the selected patients with small-sized peripheral lung cancer.

Oncological issues in staging mediastinal lymph node metastasis for left lung cancer.

OBJECTIVE: We aimed to discuss the underlying oncological issues in staging of mediastinal lymph node metastasis in patients with left lung cancer who underwent extended radical lymphadenectomy (ERL). METHODS: This multi-institutional retrospective study analyzed 116 patients with left non-small-cell lung cancer who underwent bilateral paratracheal lymph node dissection (ERL) via median sternotomy. The clinicopathological records of patients with mediastinal lymph node metastasis were examined for prognostic factors, including age, sex, histology, tumor size, cN number, preoperative data, metastatic stations (number and distribution), pT, and adjuvant chemotherapy. RESULTS: Mediastinal lymph node metastases were found in 43 patients, and right paratracheal lymph node metastases (pN3) were found in 13 patients. The 5-year overall survival rate was 25.2% in patients with pN3 tumors (n = 13) and 23.1% in patients with pN2 tumors (n = 30). The prognosis did not differ between patients with pN3 and pN2. Univariate analyses showed that histology, cN, and adjuvant chemotherapy were significant prognostic factors in patients with mediastinal lymph node metastasis. In these 43 patients, cN and adjuvant chemotherapy were significant independent prognostic factors in multivariate analysis. CONCLUSIONS: The prognostic factors for left lung cancer with mediastinal lymph node metastasis were cN status and adjuvant chemotherapy, and not pN status (pN2 or pN3). We hope that the study results, which suggest that there may be no difference in prognosis between pN2 and pN3, would broaden the discussion of oncological issues in the staging of mediastinal lymph node metastasis of left lung cancer.