A Case of Thoracic Empyema Caused by Actinomyces naeslundii.

BACKGROUND Actinomycosis is a clinically significant but uncommon infectious disease caused by anaerobic commensals of Actinomyces species, and the incidence of thoracic empyema is rare. We report an extremely rare case of empyema caused by Actinomyces naeslundii (A. naeslundii). CASE REPORT A 39-year-old man presented to our hospital with fever and dyspnea. He had massive pleural effusion and was diagnosed with a left lower-lobe abscess and left thoracic empyema. Thoracic drainage was performed and Ampicillin/Sulbactam was administered for 3 weeks. Four years later, the patient presented with back pain, and chest X-ray showed increased left pleural effusion. After close examination, malignant pleural mesothelioma was suspected, and computed tomography-guided needle biopsy was performed, which yielded a viscous purulent pleural effusion with numerous greenish-yellow sulfur granules. A. naeslundii was identified through anaerobic culture. Thoracoscopic surgery of the empyema cavity was conducted, and Ampicillin/Sulbactam followed by Amoxicillin/Clavulanate was administered for approximately 6 months. No recurrence has been observed for 1 year since the surgical procedure. CONCLUSIONS Actinomyces empyema is a rare condition, and this case is the second reported occurrence of empyema caused by A. naeslundii. The visual identification of sulfur granules contributed to the diagnosis. Long-term antibiotic therapy plays a crucial role in treatment.

Impact of central nervous system metastasis after complete resection of lung adenocarcinomas harboring common EGFR mutation - A real-world database study in Japan: The CReGYT-01 EGFR study.

OBJECTIVES: To clarify the impact of central nervous system (CNS) metastasis on performance status (PS) at relapse, on subsequent treatment(s), and on survival of patients with lung adenocarcinoma harboring common epidermal growth factor receptor (EGFR) mutation. METHODS: We conducted the multicenter real-world database study for patients with radical resections for lung adenocarcinomas between 2015 and 2018 at 21 centers in Japan. EGFR mutational status was examined at each center. RESULTS: Of 4181 patients enrolled, 1431 underwent complete anatomical resection for lung adenocarcinoma harboring common EGFR mutations. Three-hundred-and-twenty patients experienced disease relapse, and 78 (24%) had CNS metastasis. CNS metastasis was significantly more frequent in patients with conventional adjuvant chemotherapy than those without (30% vs. 20%, P = 0.036). Adjuvant chemotherapy did not significantly improve relapse-free survival at any pathological stage (adjusted hazard ratio for stage IA2-3, IB, and II-III was 1.363, 1.287, and 1.004, respectively). CNS metastasis did not affect PS at relapse. Subsequent treatment, mainly consisting of EGFR-tyrosine kinase inhibitors (TKIs), could be equally given in patients with or without CNS metastasis (96% vs. 94%). Overall survival after relapse was equivalent between patients with and without CNS metastasis. CONCLUSION: The efficacy of conventional adjuvant chemotherapy may be limited in patients with lung adenocarcinoma harboring EGFR mutations. CNS metastasis is likely to be found in practice before deterioration in PS, and may have little negative impact on compliance with subsequent EGFR-TKIs and survival after relapse. In this era of adjuvant TKI therapy, further prospective observational studies are desirable to elucidate the optimal management of CNS metastasis.

Intraoperative rapid diagnosis of pleural lavage cytology in non-small cell lung cancer.

OBJECTIVE: Positive pleural lavage cytology (PLC +) is a poor prognostic factor for non-small cell lung cancer (NSCLC). However, data on the impact of intraoperative rapid diagnosis of PLC (rPLC) are lacking. Therefore, we evaluated the efficacy of rPLC before resection during surgery. METHODS: A total of 1,838 patients who underwent rPLC for NSCLC between September 2002 and December 2014 were studied retrospectively. We assessed the clinicopathological factors between rPLC findings and the impact on survival of patients with curative resection. RESULTS: The rPLC + status was observed in 96 (5.3%) among 1,838 patients. The rPLC + group had more unsuspected N2 (30%) than the rPLC- group (p < 0.001). The 5-year overall survival (OS) of patients who underwent lobectomy or more extensive resection with rPLC + , negative rPLC (rPLC-), and microscopic pleural dissemination (PD) and/or malignant pleural effusion (PE) were 67.3, 81.3, and 11.0%, respectively. In the rPLC + group, the prognosis of patients with pN2 was equal to that of pN0-1 (5-year OS: 77.9% vs. 63.4%, p = 0.263). Undetectable dissemination in the first evaluation immediately after starting surgery was found in 9% of rPLC + patients by additional evaluation of the thoracic cavity. CONCLUSIONS: Patients with rPLC + have more favorable survival than those with microscopic PD/PE after surgery. Curative resection should be performed in patients with rPLC + , even if N2 is detected during surgery. However, the rPLC + group often has N2 upstaging; therefore, systematic nodal dissection should be performed in rPLC + patients for exact staging. rPLC may contribute to preventing oversight PD by re-evaluation during surgery.

Lung adenocarcinoma and squamous cell carcinoma difficult for immunohistochemical diagnosis can be distinguished by lipid profile.

In patients with unresectable non-small cell lung cancer, histological diagnosis is frequently based on small biopsy specimens unsuitable for histological diagnosis when they are severely crushed and do not retain their morphology. Therefore, establishing a novel diagnostic method independent of tissue morphology or conventional immunohistochemistry (IHC) markers is required. We analyzed the lipid profiles of resected primary lung adenocarcinoma (ADC) and squamous cell carcinoma (SQCC) specimens using liquid chromatography-tandem mass spectrometry. The specimens of 26 ADC and 18 SQCC cases were evenly assigned to the discovery and validation cohorts. Non-target screening on the discovery cohort identified 96 and 13 lipid peaks abundant in ADC and SQCC, respectively. Among these 109 lipid peaks, six and six lipid peaks in ADC and SQCC showed reproducibility in target screening on the validation cohort. Finally, we selected three and four positive lipid markers for ADC and SQCC, demonstrating high discrimination abilities. In cases difficult to diagnose by IHC staining, [cardiolipin(18:2_18:2_18:2_18:2)-H]- and [triglyceride(18:1_17:1_18:1) + NH4]+ showed the excellent diagnostic ability for ADC (sensitivity: 1.00, specificity: 0.89, accuracy: 0.93) and SQCC (sensitivity: 0.89, specificity: 0.83, accuracy: 0.87), respectively. These novel candidate lipid markers may contribute to a more accurate diagnosis and subsequent treatment strategy for unresectable NSCLC.

Intrapleural findings of pulmonary light-chain deposition disease.

Light-chain deposition disease is accompanied not only by characteristic CT findings but also by characteristic gross findings of the visceral pleura. Medical thoracoscopy could diagnose LCDD by the findings of the thoracic cavity.

Improved complete portal 4-port robotic lobectomy for lung cancer: Hamamatsu Method KAI.

Robot-assisted thoracoscopic surgery (RATS) has been widely used in lung cancer surgery. We previously devised a new port arrangement for RATS for lung cancer, the "Hamamatsu Method", to provide good cranial field of view using the da Vinci Xi surgical system. Our method utilizes four robot ports and one assist port, while our video-assisted thoracoscopic lobectomy technique is performed with four ports. We believe the number of ports in robotic lobectomy should not exceed those in video-assisted thoracoscopic lobectomy to preserve the advantage of minimal invasiveness. Furthermore, patients are generally more sensitive to wound size and number than surgeons assume. Thus, by combining the access and camera ports of the "Hamamatsu Method", we devised the 4-port "Hamamatsu Method KAI", which is equivalent to the conventional 5-port method, while maintaining full functionality of all four robotic arms and the assistant. "Hamamatsu Method KAI" showed comparable safety as the conventional 5- or 6-port method. Our improved 4-port method ensures minimal invasiveness while maintaining the same feasibility as the original method. The novelty of this operative method is the combined camera/assistant/access incision, and this technique is an option for RATS for lung cancer. "KAI" is a Japanese suffix indicating a sequel or successor.

The efficacy of a machine learning algorithm for assessing tumour components as a prognostic marker of surgically resected stage IA lung adenocarcinoma.

BACKGROUND: The importance of the stromal components in tumour progression has been discussed widely, but their prognostic role in small size tumours with lepidic components is not fully understood. Applying digital tissue image analysis to whole-slide imaging may enhance the accuracy and reproducibility of pathological assessment. This study aimed to evaluate the prognostic value of tumour components of lung adenocarcinoma by measuring the dimensions of the tumour consisting elements separately, using a machine learning algorithm. METHODS: Between September 2002 and December 2016, 317 patients with surgically resected, pathological stage IA adenocarcinoma with lepidic components were analysed. We assessed the whole tumour area, including the lepidic components, and measured the epithelium, collagen, elastin areas and alveolar air space. We analysed the prognostic impact of each tumour component. RESULTS: The dimensions of the epithelium and collagen areas were independent significant risk factors for recurrence-free survival (hazard ratio, 8.38; 95% confidence interval, 1.14-61.88; P = 0.037, and hazard ratio, 2.58; 95% confidence interval, 1.14-5.83; P = 0.022, respectively). According to the subgroup analysis when combining the epithelium and collagen areas as risk factors, patients with tumours consisting of both large epithelium and collagen areas showed significantly poor prognoses (P = 0.002). CONCLUSIONS: We assessed tumour components using a machine learning algorithm to stratify the post-operative prognosis of surgically resected stage IA adenocarcinomas. This method might guide the selection of patients with a high risk of recurrence.

Quantitative severity of emphysema is related to the prognostic outcome of early-stage lung cancer.

OBJECTIVES: Although pulmonary emphysema is a component of chronic obstructive pulmonary disease, the prognostic significance of the quantitative severity of emphysema in patients with primary lung cancer is unclear. This study aimed to identify the association between the quantitative severity of emphysema detected by the low-attenuation area on computed tomography and the prognostic outcome of early non-small-cell lung cancer. METHODS: A consecutive series of 1062 patients who underwent lobectomy for clinical stage I and II non-small-cell lung cancer were enrolled in this study. The clinicopathological features and long-term outcomes of patients with primary lung cancer in emphysema were investigated. The extent of emphysema in the lobe where the tumour was present was measured by preoperative computed tomography as a percentage of the low-attenuation area (LAA%). RESULTS: LAA% ≥ 1.0% was detected in 145 (13.7%) patients. LAA% was associated with pleural invasion (P < 0.0001), vascular invasion (P < 0.0001) and a larger tumour size (P = 0.001). The overall survival and recurrence-free survival in patients with LAA% ≥ 1.0% and with LAA% < 1.0% at 5 years were 78.6% and 92.1% (P < 0.0001) and 68.7% and 85.2% (P < 0.0001), respectively. According to the Cox proportional hazards model, LAA% was an independent prognostic factor for overall survival and recurrence-free survival (P = 0.0004 and P = 0.003, respectively). CONCLUSIONS: The quantitative severity of pulmonary emphysema was found to be associated with poor prognosis and clinicopathological aggression in early non-small-cell lung cancer.

Usefulness of a temporary shunt by cannulation during superior vena cava combined resection.

Superior vena cava invasive thoracic malignancy requires combined resection of the superior vena cava to achieve en bloc resection of the involved structures with negative margins. The superior vena cava combined resection requires the creation of collateral circulation from the head to the heart before performing the combined resection. Even for a short time, total superior vena cava clamping without a procedure is unsafe and should be avoided. We will present a surgical resection with superior vena cava reconstruction, involving a temporary extrathoracic shunt from the left brachiocephalic vein to the right auricle using a venous return cannula. This is an optional technique for convenient and safe superior vena cava combined resection. It provides an excellent intrathoracic surgical view by venous return via the unilateral brachiocephalic vein, with the advantages of being a simple procedure requiring short surgical time.

Placement of KANI® plate inside the chest wall for rib fixation: Prevention for organ injuries caused by crossed rib edges and plate claws.

The claw-type titanium plate has been successfully applied to manage a flail chest. However, rare and life-threatening organ injury occurs due to an insufficient claw bend. We report an ingenuity of surgical fixation using KANI® plates (USCI Japan, Tokyo, Japan) in a flail chest. A 60-year-old man with a severe flail chest underwent a surgical rib fixation. He had multiple rib fractures accompanied by dislocation and protruding crossed rib edges; we assumed a possibility of lung injury during a standard procedure in which the KANI® plates would be placed from outside the chest wall. Therefore, we placed KANI® plates inside the chest wall to ensure sufficient claw bend and to cover crossed rib edges to prevent organ injuries. We propose that our new ingenuity provides a safe and tight rib fixation in rib fractures with protruding crossed rib edges which the standard method cannot flatten.

Ubiquitin-like 3 as a new protein-sorting factor for small extracellular vesicles.

Ubiquitin-like 3 (UBL3) is a well-conserved ubiquitin-like protein (UBL) in eukaryotes and regulates the ubiquitin cascade, but the significant roles of UBL3 in cellular processes remained unknown. Recently, UBL3 was elucidated to be a post-translational modification factor that promotes protein sorting to small extracellular vesicles (sEVs). Proteins sorted into sEVs have been studied as etiologies of sEV-related diseases. Also, there have been attempts to construct drug delivery systems (DDSs) by loading proteins into sEVs. In this review, we introduce the new concept that UBL3 has a critical role in the protein-sorting system and compare structure conservation between UBL3 and other UBLs from an evolutionary perspective. We conclude with future perspectives for the utility of UBL3 in sEV-related diseases and DDS.Key words: UBL3, small extracellular vesicles, protein sorting, ubiquitin-like protein, post-translational modification.

Chylothorax after pulmonary resection and lymph node dissection for primary lung cancer; retrospective observational study.

BACKGROUND: Pulmonary resection with mediastinal lymph node dissection for treating primary lung cancer could sometimes causes chylothorax as a postoperative complication. This study examined the validity of treatments for chylothorax in our hospital. METHODS: We evaluated 2019 patients who underwent lobectomy, bilobectomy, or pneumonectomy with mediastinal lymph node dissection for primary lung cancer at Shizuoka Cancer Center Hospital, Shizuoka, Japan, between September 2002 and March 2018. The diagnostic criteria for postoperative chylothorax were that the drainage from the pleural drain was evidently white and turbid, or the pleural effusion contained a triglyceride level of > 110 mg/dL. The clinical courses and treatments were retrospectively reviewed. RESULTS: Postoperative chylothorax occurred in 37 patients (1.8%), 20 men and 17 women, with a median age of 70 years (33-80). A low-fat diet was instituted to all patients; 35 cases improved with conservative treatment, and 2 cases required reoperation. Nine cases had a drainage volume ≥ 500 mL one day following the low-fat diet commencement, which was resolved with conservative treatment and decreased drainage was observed on the third day of treatment in seven of those cases. Two cases with excessive drainage of ≥ 1000 mL in one day and systemic symptoms associated with chyle loss needed surgery. CONCLUSIONS: Even when the daily drainage volume exceeds 500 mL following a low-fat diet, there were many cases that could be cured conservatively. The indication for surgery needs to be carefully considered.

Decreased sphingomyelin (t34:1) is a candidate predictor for lung squamous cell carcinoma recurrence after radical surgery: a case-control study.

BACKGROUND: To reduce disease recurrence after radical surgery for lung squamous cell carcinomas (SQCCs), accurate prediction of recurrent high-risk patients is required for efficient patient selection for adjuvant chemotherapy. Because treatment modalities for recurrent lung SQCCs are scarce compared to lung adenocarcinomas (ADCs), accurately selecting lung SQCC patients for adjuvant chemotherapy after radical surgery is highly important. Predicting lung cancer recurrence with high objectivity is difficult with conventional histopathological prognostic factors; therefore, identification of a novel predictor is expected to be highly beneficial. Lipid metabolism alterations in cancers are known to contribute to cancer progression. Previously, we found that increased sphingomyelin (SM)(d35:1) in lung ADCs is a candidate for an objective recurrence predictor. However, no lipid predictors for lung SQCC recurrence have been identified to date. This study aims to identify candidate lipid predictors for lung SQCC recurrence after radical surgery. METHODS: Recurrent (n = 5) and non-recurrent (n = 6) cases of lung SQCC patients who underwent radical surgery were assigned to recurrent and non-recurrent groups, respectively. Extracted lipids from frozen tissue samples of primary lung SQCC were analyzed by liquid chromatography-tandem mass spectrometry. Candidate lipid predictors were screened by comparing the relative expression levels between the recurrent and non-recurrent groups. To compare lipidomic characteristics associated with recurrent SQCCs and ADCs, a meta-analysis combining SQCC (n = 11) and ADC (n = 20) cohorts was conducted. RESULTS: Among 1745 screened lipid species, five species were decreased (≤ 0.5 fold change; P < 0.05) and one was increased (≥ 2 fold change; P < 0.05) in the recurrent group. Among the six candidates, the top three final candidates (selected by AUC assessment) were all decreased SM(t34:1) species, showing strong performance in recurrence prediction that is equivalent to that of histopathological prognostic factors. Meta-analysis indicated that decreases in a limited number of SM species were observed in the SQCC cohort as a lipidomic characteristic associated with recurrence, in contrast, significant increases in a broad range of lipids (including SM species) were observed in the ADC cohort. CONCLUSION: We identified decreased SM(t34:1) as a novel candidate predictor for lung SQCC recurrence. Lung SQCCs and ADCs have opposite lipidomic characteristics concerning for recurrence risk. TRIAL REGISTRATION: This retrospective study was registered at the UMIN Clinical Trial Registry ( UMIN000039202 ) on January 21, 2020.

Impact of Positive Pleural Lavage Cytology for Each Stage of Non-Small Cell Lung Cancer Patients.

BACKGROUND: Positive preresection pleural lavage cytology (PLC+) is a poor prognostic factor in non-small cell lung cancer (NSCLC). This study evaluated the prognostic value of PLC+ for the different pathologic stages (p-stages) of NSCLC. METHODS: A retrospective analysis was conducted of all 1293 staged patients who underwent curative resection in the Shizuoka Cancer Center Hospital, Shizuoka, Japan, for NSCLC to evaluate the impact of PLC+ on survival, specifically in patients with p-stage I NSCLC. The survival rate between patients with and without PLC+ was compared using the Kaplan-Meier method with the log-rank test for comparison. RESULTS: PLC+ was identified in 50 of the 1293 patients (3.9%) and was correlated with lymph node metastasis (P < .001), a pathologic tumor size larger than 3 cm (P = .033), the presence of pleural invasion (P < .001), and adenocarcinoma (P = .038). In patients with PLC+, the 5-year disease-free survival (DFS) was 31.1%, compared with 75.7% for patients with a negative PLC (PLC-) (P < .001). On multivariate analysis, the PLC+ status was an independent prognostic factor of DFS (hazard ratio 1.70; P = .013). Among the 818 patients with p-stage I NSCLC, PLC+ was identified in 22, with a 5-year DFS of 40.4%. The prognosis in patients with p-stage I NSCLC with PLC+ was equal to that in patients with p-stage IIIA NSCLC with PLC- (5-year DFS, 40.4% and 39.0%). CONCLUSIONS: PLC is an independent prognostic factor in early-stage NSCLC. Therefore, it may be appropriate to up-stage an NSCLC diagnosis in the presence of PLC+, especially for patients with p stage I.

An endobronchial recurrence of resected lung adenocarcinoma.

We report a rare case of endobronchial metastasis arising from peripheral lung adenocarcinoma 12 months after its complete resection. A 69-year old man underwent left upper lobectomy and lymph node dissection. A year after surgery, a bronchial nodule was identified at the left main bronchus through a computed tomography study. A bronchoscope examination showed that the bronchial nodule in the cartilage was located apart from the stump of the upper bronchus. Thus, bronchoscopic resection was performed. The pathological diagnosis was papillary adenocarcinoma, which was identical to the pathology of the previously resected lung cancer. Endobronchial metastasis from the primary lung cancer was confirmed. The present case highlights that clinicians should pay more attention to this rare recurrence pattern of lung cancer.

Uniquely Modified Robotic-Assisted Thoracic Surgery With Good Intrathoracic Visual Field.

Although the use of robot-assisted thoracoscopic surgery is increasing rapidly, it allows only a limited visual field on the head side because the system's camera port is usually placed in the eighth or ninth intercostal space. Because the visual field on the intrathoracic head side is critical during lung cancer surgery, such as when peeling off the first branches of the pulmonary artery (right truncus superior artery or left upper ventral lobe branch), a poor visual field could be fatal. We therefore devised a new port arrangement, the "Hamamatsu method," which ensures a good visual field.

8th Edition Tumor, Node, and Metastasis T-Stage Prognosis Discrepancies: Solid Component Diameter Predicts Prognosis Better than Invasive Component Diameter.

The biggest change in the 8th edition of the tumor, lymph node, and metastasis (TNM) classification is the recommendation of the solid component diameter and invasive size for determining the clinical and pathological T-factor, respectively. Here, we validated new proposals for the Lung Cancer TNM classification's revision and compared clinical and pathological T-stages. We retrospectively analyzed 177 cases of non-small cell lung cancers without lymph node metastasis, and involving complete resection, that occurred in our department between January 2017 and March 2019. We reviewed the overall tumor diameter, solid component diameter, and clinical T-factor on computed tomography (CT), and the pathological tumor diameter, pathological invasion diameter, pathological T-factor, and prognosis. The difference between the pathological invasive size and solid size on CT was within 5 mm in 99 cases (56%). At a two-year recurrence-free survival rate, the clinical T-stage demonstrated a better prognostic outcome than the pathological T-stage. Despite including the benign findings, the solid component diameter was better correlated with prognosis than the invasive size. Therefore, in cases of discrepancies of clinically and pathologically detected tumor size, the solid CT size should also be used for the pathological T classification.

Solitary peribronchiolar metaplasia showing a sub-solid nodule on computed tomography.

Recent advances in radiographic imaging and thoracic surgery have facilitated surgery for small lung tumors by eliminating the need for pathological diagnosis. To date, we have experienced two cases of small lung tumors that were surgically resected without pathological diagnosis as malignant. Computed tomography (CT) revealed sub-solid nodules in the peripheral lung. After tumor resection, both tumors were pathologically diagnosed as peribronchiolar metaplasia. To the best of our knowledge, solitary peribronchiolar metaplasia showing a sub-solid nodule on CT imaging has not previously been reported.

Quantitative computed tomography for predicting cardiopulmonary complications after lobectomy for lung cancer in patients with chronic obstructive pulmonary disease.

OBJECTIVES: In lung cancer resection, chronic obstructive pulmonary disease is a risk factor for post-operative complications. Few studies on post-operative complications of lung cancer resection have considered radiographic emphysematous change as an index. Here, we have examined the relationship between the regional ratio of the emphysematous area in pre-operative computed tomography images and cardiopulmonary complications in patients with chronic obstructive pulmonary disease who underwent lung cancer resection. METHODS: We retrospectively evaluated 159 patients with chronic obstructive pulmonary disease who underwent lobectomy for lung cancer at Shizuoka Cancer Center Hospital, Shizuoka, Japan, between 2002 and 2011. Pre-operative factors, including the proportion of the emphysematous area measured by computed tomography as a percentage of the low attenuation area (LAA%), as well as intraoperative factors were analyzed. Cardiopulmonary complications, including pyothorax, pneumonia and atelectasis, acute pulmonary injury, indwelling chest tube, long duration of oxygen supply, and arrhythmia, were evaluated. RESULTS: Cardiopulmonary complications were observed among 61 patients (38%). Univariate analysis revealed that patient age, percentage of forced expiratory volume in 1 s, LAA%, and volume of blood loss were significantly associated with cardiopulmonary complications. Multivariate analysis indicated patient age and LAA% as being significant independent predictors of cardiopulmonary complications. CONCLUSIONS: The regional ratio of the emphysematous area is useful for predicting cardiopulmonary complications in patients with chronic obstructive pulmonary disease who undergo lobectomy for lung cancer. In such patients who are also ≥ 70 years of age and exhibit LAA% ≥ 1.0%, careful intra- and post-operative management is warranted.

Outcomes and predictive factors for pathological node-positive in radiographically pure-solid, small-sized lung adenocarcinoma.

OBJECTIVES: The indication of limited resection for radiographically pure-solid, small-sized lung adenocarcinoma is controversial. This study aimed to reveal the long-term outcome of standard surgical treatment and determine the predictive factors for pathological lymph node metastasis in optimal candidates undergoing limited surgical resection for pure-solid, small-sized lung adenocarcinoma. METHODS: The medical records of 107 consecutive patients were retrospectively reviewed at our hospital between December 2002 and December 2013. Inclusion criteria were histopathological diagnosis of lung adenocarcinoma, radiographically pure-solid tumor, ≤ 2 cm tumor size measured using thin-section computed tomography, clinical N0M0, patients who underwent lobectomy with systematic or lobe-specific lymph node dissection, and R0 resection. Overall and disease-free survival curves were calculated using the Kaplan-Meier method. Clinicopathological factors predicting pathological node-positive metastasis were identified by univariate and multivariate analysis. RESULTS: The 5-year overall and disease-free survival rates were 91.4% and 87.3%, respectively. Multivariate analysis demonstrated maximum standardized uptake value > 5 as the independent predictor of pathological node-positive metastasis (odds ratio 3.81; 95% confidence interval 1.25-12.3; p = 0.02). In all patients, the pathological node-positive rate was 16.7%; in patients who had a maximum standardized uptake value of ≤ 5, the rate was 7.9%. CONCLUSION: The long-term outcome of standard surgical treatment was favorable. Maximum standardized uptake value was a significant predictor of pathological node-positive metastasis; however, diagnostic accuracy was not favorable. Therefore, the selection of optimal candidates is difficult, and limited surgical resection may not be applicable in pure-solid, small-sized lung adenocarcinoma.