Impact of intrapulmonary tumour location of non-small-cell lung cancer on surgical outcomes for segmentectomy.

OBJECTIVES: While segmentectomy is considered a viable option for small peripheral non-small-cell lung cancer, its efficacy for central lesions remains uncertain. This study aimed to assess the oncological outcomes of segmentectomy for central lesions compared to peripheral ones. METHODS: We retrospectively examined 338 clinical stage IA non-small-cell lung cancer patients who underwent thoracoscopic anatomical segmentectomy at our institution from January 2013 to December 2021. Patients were divided into 2 groups based on intrapulmonary tumour location: inner two-thirds (central group, n = 82) and outer one-third (peripheral group, n = 256). RESULTS: The gender, body mass index, performance score, smoking, comorbidities and preoperative pulmonary function were similar in both groups. On computed tomography images, tumour diameter and consolidation-to-tumour ratio were comparable between the groups. The central group had significantly greater tumour-to-pleura distances [mm, 23 (18-27) vs 11 (8-14); P < 0.001], shorter margin distances [mm, 20 (15-20) vs 20 (20-20); P < 0.001] and larger resected lung volumes based on subsegment count [4 (3-6) vs 3 (3-5); P = 0.004] than the peripheral group. Surgery duration, bleeding, hospitalization or drainage period, mortality, readmission and pathological stage were equivalent between the groups. The central group showed significantly more postoperative pleural effusions (5% vs 1%; P = 0.03) than the peripheral group, with no adverse impact on postoperative pulmonary functions. During the follow-up period, local-only recurrence rates were 0% and 8% in the respective groups (Gray test P = 0.07), and total recurrence rates were 6% and 11% (Gray test P = 0.70), with no significant differences. Moreover, no significant inter-group difference in overall survival rates was observed (82% vs 93%; P = 0.15). CONCLUSIONS: Segmentectomy may be a promising therapeutic option for early-stage non-small-cell lung cancer located in the inner two-thirds of the parenchyma.

Usefulness of the Global Leadership Initiative on malnutrition (GLIM) criteria in preoperative nutritional assessment of patients with primary lung cancer.

BACKGROUND AND AIMS: The Global Leadership Initiative on Malnutrition (GLIM) developed a new method for evaluating malnutrition; however, no consensus has been reached regarding the use of these criteria. Therefore, this study aimed to investigate the association between nutritional status assessed using the GLIM criteria and outcomes of lung cancer after surgery. METHODS: Patients with non-small cell lung cancer who underwent lung resection and bioelectrical impedance analysis to estimate muscle mass before surgery were included. Their background, pathological stage, recurrence, and prognosis were investigated. Patients were divided into two groups according to the GLIM criteria: normal nutrition and malnutrition groups. RESULTS: The normal and malnutrition groups comprised 110 and 88 patients, respectively. Malnutrition was significantly associated with poor overall survival after surgery (P = 0.025) but not with disease-free survival. Multivariate analysis showed that malnutrition (hazard ratio [HR]:2.374, P = 0.020), advanced pathological stage of lung cancer (HR: 1.919, P = 0.002), and the presence of postoperative complications (HR: 2.035, P = 0.047) were significantly associated with poor overall survival. CONCLUSION: Malnutrition assessed using the GLIM criteria was associated with the prognosis of patients with postoperative non-small cell lung cancer. Preoperative assessment using the GLIM criteria would allow for effective nutritional and rehabilitative interventions to improve prognosis.

The possibility of mutations of RAS signaling genes and/or TP53 in combination as a negative prognostic impact on pathological stage I non-small cell lung cancer.

BACKGROUND: The recurrence rate of non-small cell lung cancer (NSCLC) is as high as 30%, even in the cancer with pathological stage I disease. Therefore, identifying factors predictive of high-risk pathological recurrence is important. However, few studies have examined the genetic status of these tumors and its relationship to prognosis. MATERIALS AND METHODS: A cohort of 328 cases of primary lung cancer that underwent complete resection at Tokyo Medical and Dental University (TMDU) was screened for 440 cancer-associated genes using panel testing. Further analyses included 92 cases of pathological stage I NSCLC who did not receive adjuvant chemotherapy. Ridge regression was performed to identify association studies mutational status and postoperative recurrence. These data were then validated using clinical and genetic data from 56 patients in The Cancer Genome Atlas (TCGA). RESULTS: Mutations in TP53, RAS signaling genes KRAS and HRAS, and EGFR were recurrently detected. Ridge regression analysis relevant to recurrence, as well as survival analysis, performed using data from the TMDU cohort revealed significantly shorter relapse-free survival (RFS) for patients with RAS signaling or TP53 gene mutations than for those without (log-rank test, p = 0.00090). This statistical trend was also suggested in the TCGA cohort (log-rank test, p = 0.10). CONCLUSION: Mutations in RAS signaling genes and/or TP53 could be useful for the prediction of shorter RFS of patients with stage I NSCLC.

Extubation by supraglottic airway after lobectomy prevents cough-associated air leaks and prolonged coughing or sore throat.

OBJECTIVES: Double-lumen endobronchial tubes (DLTs) are essential for differential lung ventilation during pulmonary lobectomy, but they are more rigid, longer, larger in diameter and irritable. Coughing at extubation sometimes causes airway and lung injury, which causes severe air leaks, prolonged cough and sore throat. We examined the prevalence of cough-associated air leaks at extubation and postoperative cough or sore throat after lobectomy and evaluated the efficacy of supraglottic airway (SGA) in preventing these complications. METHODS: Patient characteristics and operative and postoperative factors data were collected from patients who underwent pulmonary lobectomy between January 2013 and March 2022. After propensity score matching, these data were compared between the SGA and DLT groups. RESULTS: A total of 1069 patients with lung cancer (SGA, 641; DLTs, 428) were enrolled and coughing at extubation occurred in 100 (23.4%) patients in the DLT group, 65 (65.0%) showed increased cough-associated air leaks at extubation and 20 (30.8%) showed prolonged air leaks. Coughing at extubation occurred in 6 (0.9%) in the SGA group. In 193 patients from each group after propensity score matching, coughing at extubation and the associated air leak increase were significantly lower in the SGA group. Visual analogue scale of postoperative cough and sore throat on postoperative days 2, 7 and 30 were significantly lower in the SGA group. CONCLUSIONS: SGA is effective and safe for preventing cough-associated air leaks and prolonged postoperative cough or sore throat at extubation following pulmonary lobectomy.

Endovascular Treatment for Acute Ischemic Stroke After Video-Assisted Thoracoscopic Pulmonary Lobectomy in Patients With Lung Cancer: A Report of Four Cases and Literature Review.

BACKGROUND: Postoperative cerebral embolic stroke is a serious complication of pulmonary lobectomy, occurring in 1.1% of patients undergoing lobectomy through video-assisted thoracoscopic surgery (VATS). The mechanism of this complication is thought to be embolic stroke caused by thrombus formed due to stagnation in the pulmonary vein stump after VATS lobectomy. There have been few reports demonstrating the utility of endovascular treatment (EVT) for cerebral embolic stroke after VATS lobectomy. CASE DESCRIPTION: In our case series, cerebral embolic stroke occurred after VATS pulmonary lobectomy for lung cancer, including the left upper lobe in three cases and the right lobe in one. The median duration of ischemic stroke after VATS was 4.5 days (interquartile range, 2-9 days). The median time from stroke onset to puncture was 130 min. Successful recanalization was achieved in all cases, and two patients achieved favorable clinical outcomes (modified Rankin scale, 0-2). CONCLUSION: We report a case series of four patients who underwent EVT for acute embolic stroke after VATS lobectomy for lung cancer. EVT is considered a reasonable and feasible therapeutic option for this condition.

Sensitivity to dabrafenib and trametinib treatments in patients with non-small-cell cancer harboring BRAF compound mutations: A pooled analysis of BRAF p.V600E-positive advanced non-small-cell lung cancer.

PURPOSE: The present study clarified the sensitivity of the BRAF tyrosine kinase inhibitor mechanism in patients with BRAF compound mutation and predicted the sensitivity using molecular dynamics simulation. METHODS: We examined 16 BRAF tumors with p.V600E-positive non-small-cell lung cancer. RESULTS: One patient (6.2%) had a BRAF p.V600E and p.K601_W604 compound mutation with a good clinical response to dabrafenib and trametinib. Molecular dynamics simulation also complemented the effect. CONCLUSIONS: The combination of a genetic analysis and computational simulation model may help predict the sensitivity for dabrafenib in cases with a rare BRAF compound mutation. The construction of a genomic and simulation fused database is important for the development of personalized medicine in this field.

Pulmonary Mucormycosis Involving the Left Main Bronchus and the Pulmonary Artery.

Pulmonary mucormycosis is an extremely rare disease. It often occurs in immunocompromised patients, such as patients with diabetes and those on long-term steroid use. The prognosis of the disease is poor despite the administration of antifungal agents and removal of the necrotic tissue. Herein, we present a successfully treated case of pulmonary mucormycosis in a patient with type 2 diabetes who underwent left pneumonectomy because of the involvement of the left main pulmonary artery and the left main bronchus. Irrespective of the infected organ, complete debridement of the infected tissue and treatment with antifungal agents are essential for treating mucormycosis.

Postoperative Delirium in Lung Cancer Anatomical Resection-Analysis of Risk Factors and Prognosis.

BACKGROUND: The incidence of postoperative delirium after anatomical lung resection ranges from 5 to 16%. This study aimed to analyze the risk factors and prognosis of postoperative delirium in anatomical lung resection for lung cancer. METHODS: This study included 1351 patients undergoing anatomical lung resection between April 2010 and October 2020. We analyzed the perioperative risk factors of postoperative delirium. We also compared postoperative complications and survival between the delirium and non-delirium groups. RESULTS: Postoperative delirium was identified in 44 (3.3%) of 1351 patients who underwent anatomical lung resection for lung cancer. Age, peripheral vascular disease, depression, and current smoking status were independent risk factors for postoperative delirium in the multivariate analysis. The percentage of postoperative delirium was 0.6% in never smokers and 6.0% in current smokers. The delirium and non-delirium groups showed significant differences in overall survival (p = 0.0144) and non-disease-specific survival (p = 0.0080). After propensity score matching, the two groups did not significantly differ in overall survival (p = 0.9136), non-disease-specific survival (p = 0.8146), or disease-specific survival (p = 0.6804). CONCLUSIONS: Age, peripheral vascular disease, depression, and current smoking status were considered independent risk factors for postoperative delirium in anatomical lung resection for lung cancer. Smoking cessation for at least four weeks before surgery is recommended for reducing incidence of post-operative delirium.

Successful excision of a giant subcarinal bronchogenic cyst by video-assisted thoracoscopic surgery.

Mediastinal bronchogenic cysts, regarded as congenital foregut abnormalities, are uncommon. These cysts can compress adjacent structures, causing obstructive symptoms and complications. A 57-year-old man was admitted to our hospital with complaints of tachycardia, dyspnea, and chest pain. Enhanced computed tomography revealed a 90 × 90 mm, well-defined subcarinal cystic mass causing significant compression and stenosis of the right main bronchus, right pulmonary artery, and right inferior pulmonary vein. The mass was successfully excised using one window and two-port video-assisted thoracoscopic surgery with partial resection and repair of pulmonary artery, and the postoperative course was good with no recurrence.

Novel Resistance Mechanisms Including L1196Q, P1094H, and R1248_D1249 Insertion in Three Patients With NSCLC After ALK Tyrosine Kinase Inhibitor Treatment.

OBJECTIVES: The purposes of this study are to clarify the details of the ALK tyrosine kinase inhibitor (TKI) resistance mechanism in rebiopsy cases and to predict novel resistance gene alterations using molecular dynamics simulation. METHODS: A total of 21 patients with ALK-positive NSCLC who underwent a rebiopsy after ALK TKI failure were included in this analysis. ALK fluorescence in situ hybridization and reverse transcription polymerase chain reaction were performed with paired initial and rebiopsy tumor specimens. RESULTS: Nine patients had no known ALK resistance mechanisms. Four had ALK amplification. L1196M, I1171N, and G1269A, mutations that are known to indicate resistance to ALK TKIs, were detected in one patient each. Small cell carcinoma and sarcomatoid transition were found in one case each. L1196Q, P1094H, and exon 24 76-base pair insertion were detected after the second-generation ALK TKIs. CONCLUSIONS: The combination of a genetic analysis and a computational simulation model may make a prediction of resistance mechanisms for overcoming ALK TKI resistance, and the construction of a genomic and simulation fused database is important for the development of personalized medicine in this field.

Postoperative Atrial Fibrillation in Lung Cancer Lobectomy-Analysis of Risk Factors and Prognosis.

BACKGROUND: The incidence of postoperative atrial fibrillation (POAF) after pulmonary lobectomy ranges from 6.4 to 12.6%. This study aimed to analyze the postoperative risk factors and prognosis for POAF in lobectomy for lung cancer. METHODS: Data were collected from patients undergoing pulmonary lobectomy from April 2010 to March 2019. We analyzed risk factors for POAF among perioperative factors and compared postoperative complications or overall survival between POAF and non-POAF groups. We classified POAF as either the temporary or non-temporary type and compared perioperative factors, postoperative complications, and overall survival. RESULTS: POAF was identified in 49 (5.2%) of the 947 lobectomies. The POAF group included more males, patients with poor performance status (PS), history of paroxysmal atrial fibrillation (AF), chronic obstructive pulmonary disease (COPD), and intraoperative blood transfusions. Poor PS, COPD, previous paroxysmal AF, and intraoperative blood transfusion were independent risk factors for POAF in multivariate analysis. The POAF group had a poorer prognosis than the non-POAF group (p = 0.0045). POAF was divided into 29 temporary and 20 non-temporary types. The onset date of non-temporary-type POAF was significantly later than that of the transient type (P < 0.01), and diabetes mellitus was significantly higher in non-temporary-type POAF. Non-temporary-type POAF had a significantly poorer prognosis in terms of overall survival (p = 0.005). CONCLUSIONS: Poor PS, COPD, history of PAF, and intraoperative blood transfusion were independent risk factors for POAF. Non-temporary-type POAF occurred significantly later than transient type and caused poorer prognosis after lobectomy for lung cancer.

Targeted RNA sequencing with touch imprint cytology samples for non-small cell lung cancer patients.

BACKGROUND: RNA-based sequencing is considered ideal for detecting pathogenic fusion-genes compared to DNA-based assays and provides valuable information about the relative expression of driver genes. However, RNA from formalin-fixed paraffin-embedded tissue has issues with both quantity and quality, making RNA-based sequencing difficult in clinical practice. Analyzing stamp-derived RNA with next-generation sequencing (NGS) can address the above-mentioned obstacles. In this study, we validated the analytical specifications and clinical performance of our custom panel for RNA-based assays on the Ion Torrent platform. METHODS: To evaluate our custom RNA lung panel, we first examined the gene sequences of RNA derived from 35 NSCLC tissues with diverse backgrounds by conventional methods and NGS. Next, we moved to the clinical phase, where clinical samples (all stamp-derived RNA) were used to examine variants. In the clinical phase we conducted an NGS analysis while simultaneously applying conventional approaches to assess the feasibility and validity of the panel in clinical practice. RESULTS: In the prerun phase, all of the variants confirmed with conventional methods were detected by NGS. In the clinical phase, a total of 80 patients were enrolled and 80 tumor specimens were sequenced from February 2018 to December 2018. There were 66 cases in which the RNA concentration was too low to be measured, but sequencing was successful in the vast majority of cases. The concordance between NGS and conventional methods was 95.0%. CONCLUSIONS: RNA extraction using stamp specimens and panel sequencing by NGS were considered applicable in clinical settings. KEY POINTS: Significant findings of the study Next-generation sequencing using RNA from stamp specimens was able to detect driver gene changes in non-small cell lung cancer including fusion genes with the same accuracy as conventional methods. What this study adds Using RNA from stamp specimens obtained from biopsy increases the number of candidate cases for RNA sequencing in clinical settings.

Negative reactions of BRAF mutation-specific immunohistochemistry to non-V600E mutations of BRAF.

BRAF mutations are rare driver mutations in non-small cell lung cancer (NSCLC), accounting for 1%-2% of the driver mutations, and the mutation spectrum has a wide range in contrast to other tumors. While V600E is a dominant mutation in melanoma, more than half of the mutations in NSCLCs are non-V600E. However, treatment with dabrafenib plus trametinib targets the BRAF V600E mutation exclusively. Therefore, distinguishing between V600E and non-V600E mutations is crucial for biomarker testing in NSCLC in order to determine treatment of choice. Immunohistochemistry (IHC) using the BRAF V600E mutation-specific antibody is clinically used in melanoma patients, but little is known about its application in NSCLC, particularly with regard to the assay performance for non-V600E mutations. In the present study, we examined 117 tumors with BRAF mutations, including 30 with non-V600E mutations, using BRAF mutation-specific IHC. None of the tumors with non-V600E mutations, including two compound mutations, showed a positive reaction. Furthermore, all V600E mutations were positive except for one case with combined BRAF V600E and K601_W604 deletion. Our findings confirmed that the BRAF V600E mutation-specific IHC is specific without any cross-reactions to non-V600E mutations, suggesting that this assay can be a useful screening tool in clinical practice.

Long-Term Recurrence of Completely Resected NSCLC.

INTRODUCTION: The aim of this study is to evaluate the clinical backgrounds, including driver mutations, of those patients with early stage NSCLC who experienced recurrence beyond 5 years after complete resection. METHODS: We used a cohort of 512 consecutive cases of surgically resected NSCLC without other malignances from 2006 to 2011 in Aichi Cancer Center Hospital. The inclusion criteria for this cohort were patients with primary NSCLC who underwent a surgically curable operation. RESULTS: A total of 172 patients (32.8%) had recurrence after the surgery. Among the recurrent cases, 17 patients (3.3%) had a relapse more than 5 years after the surgery, and all except one (16 of 17, 94.1%) had driver mutations, including gene rearrangements. CONCLUSIONS: Even in early stage NSCLC after complete resection, it was found that some cases had a relapse more than 5 years after the surgery. Most of these cases had some kind of driver mutations; so more than 5 years of postoperative surveillance may be beneficial, especially in those with driver gene mutants.

Calculating the Tumor Nuclei Content for Comprehensive Cancer Panel Testing.

Comprehensive genetic panel testing generally requires that the analyzed tissues have a percent tumor nuclei (%TN) content of 20% or more to achieve assay performance comparable to the validated specifications. Pathologists play a crucial role in ensuring that the optimal results are achieved by accurately assigning %TN content of the available specimens and selecting the best material to submit for sequencing. This study addresses the issues in evaluating %TN, such as intraobserver variability, and examines whether focused training and feedback can improve pathologist performance. Nine referring institution pathologists (all board-certified and working at the core institute and the alignment hospitals under the National Cancer Genome scheme) evaluated 18 tumors that had been subjected to comprehensive genetic panel testing with the FoundationOne CDx assay. The %TN estimates provided by referring institution pathologists were compared with two standards: %TN assigned by the tumor sequencing institution's pathologist (a board-certified pathologist at Foundation Medicine, Inc.) and the computational %TN estimated from the mutant allele frequencies after sequencing was completed. The pathologists generally overestimated %TN in the first pretraining round of the evaluation, and the differences in the averaged %TN from the tumor sequencing institution and computational standards were statistically significant. However, the posttraining second-round results became significantly concordant with the standards. This study suggests that %TN content is empirically overestimated but the evaluation skill can be improved by providing a training and feedback program.

Higher frequency of occult lymph node metastasis in clinical N0 pulmonary adenocarcinoma with ALK rearrangement.

OBJECTIVES: There have been few studies that have fully elucidated the relationship between genomic mutations in pulmonary adenocarcinomas and occult lymph node (LN) metastases (pN1-2) despite a preoperative clinical N0 stage (cN0). It is well known that anaplastic lymphoma kinase (ALK) rearrangements are more likely to occur in younger patients with high grade tumors. The aim of this study was to investigate the genomic status, examine the clinicopathologic features, and evaluate whether ALK mutations are associated with occult LN metastases. MATERIALS AND METHODS: We retrospectively evaluated 459 Japanese patients who underwent pulmonary resection of cN0 adenocarcinomas between January 2012 and December 2015. The clinicopathologic characteristics, including age, sex, smoking index, tumor maximum diameter and consolidation/tumor ratio on computed tomography (CT), maximum standardized uptake value on positron emission tomography (PET) and gene mutations (epidermal growth factor receptor [EGFR], ALK, and kirsten ras genes (KRAS), were evaluated. RESULTS: ALK and EGFR and KRAS mutations were all mutually exclusive. Among 324 patients found to have mutations, ALK was involved in 19 (5.9%), EGFR in 266 (82.1%), and KRAS in 39 (12.0%). The incidence of occult LN metastases did not differ significantly between those with or without mutations (p=0.27). On univariate and multivariate analyses, tumors with ALK were more likely to have occult LN metastases (p=0.03). In cN0 tumors with ALK, pN1 was diagnosed in 26.3% and pN2 in 10.5%, whereas pN1 or pN2 stage was found in <10.0% in those with EGFR or KRAS mutations or with no mutations at all. No significant difference was found in the 2-year disease-free survival among those with gene mutations (p=0.08). CONCLUSION: This study highlights the frequency of PET- and CT-negative occult LN metastases in resected adenocarcinomas with ALK rearrangement. Our multivariate analysis showed that ALK rearrangements were associated with a significantly higher incidence of occult LN metastasis compared with ALK-negative adenocarcinomas.

Two cases of combined thoracoscopy and open chest surgery for locally advanced lung carcinoma.

Thoracoscopic surgery is becoming more widely used in thoracic surgery and has an increasingly important role to play. However, its use for locally advanced carcinoma (clinical stage T3-4) remains controversial. We adapted our procedure by combining thoracoscopy and open chest surgery (combination surgery) with the aim of reducing invasiveness while ensuring that the operation is safe and curative. Here we describe our experience. Case 1 was a man in his 60s who underwent induction chemoradiotherapy (cisplatin plus vinorelbine plus 40 Gy radiotherapy) followed by radical surgery for a left apical lung carcinoma with chest wall invasion. Case 2 was a woman in her 70s who repeatedly had pneumonia and who underwent radical surgery for left apical adenocarcinoma that was expected to have strong adhesions to the thoracic wall. A thoracotomy incision may be required in cases of stage T3-4 lung cancer to access the hilar region and dissect the resected tumor and surrounding organs. In such cases, adding thoracoscopy to either one of these procedures may enable the use of a smaller incision in the chest wall. In both cases, complete resection with no residual tumor or complications was achieved, with the patients being discharged 3-8 days postoperatively. Cases 1 and 2 both remain recurrence free after 1.5 and 3 years, respectively). This suggests that having a thorough understanding of the features of both thoracoscopic and open chest surgery and integrating the two may enable surgery to be safely and less invasively performed while ensuring a curative effect.

Mediastinal pulmonary artery is associated with greater artery diameter and lingular division volume.

Pulmonary vessels have numerous variation and aberrant branching patterns. Mediastinal lingular artery (MLA), the most common aberrant branch, might contribute to greater blood flow to lingular division. Hence, we investigated a correlation between lingular division volume and MLA using three-dimensional CT volumetry. We included 199 consecutive patients who underwent surveillance chest CT to detect possible malignancies in April 2015. We measured lingular division volume and cross-sectional area of lingular arteries using three-dimensional CT volumetry. MLA was identified in 58 cases (29.1%). The MLA group had significantly greater lingular division volume (median ± quartile deviation: 378.3 ± 75.5 mL vs. 330.0 ± 87.5 mL; p = 0.021) and percentage lingular division to left lung volume (19.0 ± 2.62% vs. 16.6 ± 2.39%; p < 0.001) than the non-MLA group. Total cross-sectional area of lingular arteries of the MLA group was significantly larger than that of the non-MLA group (46.1 ± 9.46 vs. 40.2 ± 5.76 mm2; p = 0.003). The total cross-sectional area of the lingular arteries strongly correlated to the percentage of lingular division to left lung volume (r = 0.689, p < 0.001). This is the first report demonstrating a positive correlation between branching pattern of pulmonary artery and lung volume.

Postoperative chylothorax after pulmonary wedge resection in two patients who underwent radical neck dissection: A case report.

Postoperative chylothorax after wedge resection without mediastinal lymph node dissection is extremely rare. Herein, we report two cases: one case of postoperative chylothorax that developed after wedge resection and another of expanded collaterals detected during thoracoscopic surgery. We believe the cause of this complication to be the history of neck and pulmonary ligament dissections during pulmonary surgery.

Predictors of indocyanine green visualization during fluorescence imaging for segmental plane formation in thoracoscopic anatomical segmentectomy.

BACKGROUND: To determine factors predicting indocyanine green (ICG) visualization during fluorescence imaging for segmental plane formation in thoracoscopic anatomical segmentectomy. METHODS: Intraoperatively, the intravenous ICG fluorescence imaging system during thoracoscopic anatomical segmentectomy obtained fluorescence emitted images of its surfaces during lung segmental plane formation after the administration of 5 mg/body weight of ICG. The subtraction of regularization scale for calculating the exciting peaks of ICG between the planned segments to resect and to remain was defined as ΔIntensity (ΔI). Variables such as the ratio of forced expiratory volume in 1 s to forced vital capacity (%FEV1.0), smoking index (SI), body mass index (BMI), and low attenuation area (LAA) on computed tomography (CT) took a leading part. RESULTS: The formation of the segmental plane was successfully accomplished in 98.6% segments and/or subsegments. SI and LAA significantly affected ΔI levels. The area under the receiver operating characteristic curve for the %FEV1.0, SI, and LAA was 0.56, 0.70, and 0.74, respectively. SI >800 and LAA >1.0% were strong predictors of unfavorable ICG visibility (P=0.04 and 0.01, respectively). CONCLUSIONS: Fluorescence imaging with ICG was a safe and effective method for segmental plane formation during thoracoscopic anatomical segmentectomy. In spite of its high success rate, unfavorable visibility may potentially occur in patients who are heavy smokers or those with a LAA (>1.0%) on CT.