Risk of Death From Other Diseases in Lung Cancer Patients After Sublobar Resection Versus Lobectomy.

BACKGROUND AND OBJECTIVES: A recent Japanese phase three clinical trial for lung cancer suggested a possible advantage of segmentectomy over lobectomy in terms of death from other diseases. This study aimed to compare the risk of death from other diseases based on surgical procedures in lung cancer patients without recurrence. METHODS: We retrospectively reviewed 2121 patients without disease recurrence after curative resection for lung cancer at our institution. Patient characteristics and overall survival were compared between sublobar resection and lobectomy. RESULTS: The sublobar group (n = 595) had a significantly higher proportion of women, non-smokers, patients without comorbidities, patients with a history of other cancers, and patients with earlier-staged disease when compared with the lobectomy group (n = 1526). The overall survival was significantly longer in the sublobar group than in the lobectomy group (p = 0.0034). After adjusting for background characteristics in an analysis of 488 patients, the overall survival had a trend to be longer in the sublobar group than in the lobectomy group (p = 0.071). CONCLUSIONS: Our results suggested that the risk of death from other diseases was potentially higher after lobectomy than after sublobar resection. Although several clinical factors could influence the results, these results may support the benefit of sublobar resection, assuming that the curability of both procedures is similar.

Ringlike Peripheral Increased Iodine Concentration for the Differentiation of Primary Lung Cancer and Pulmonary Metastases on Contrast-Enhanced Dual-Energy CT.

BACKGROUND. Differentiation of primary lung cancers and pulmonary metastases may present a diagnostic dilemma given overlapping CT findings. OBJECTIVE. The purpose of this study was to compare the utility of ringlike peripheral increased iodine concentration and conventional findings for differentiating primary lung cancers from pulmonary metastases on dual-energy CT (DECT). METHODS. This retrospective study included 93 patients (64 men, 29 women; median age, 70 years) who underwent resection of a primary lung cancer (n = 68) or pulmonary metastasis (n = 25) corresponding to a solid lesion on preoperative contrast-enhanced DECT performed between April 2020 and March 2021. Venous phase 120-keV single-energy images, equilibrium phase 66-keV virtual monoenergetic images, and iodine concentration maps were reconstructed. Two radiologists independently assessed lesions for spiculated margins, air bronchograms, rim enhancement, and thin ringlike peripheral high iodine concentration; differences were resolved by consensus. Inter-reader agreement and diagnostic performance were assessed. Multivariable logistic regression analysis incorporated additional patient and lesion characteristics. RESULTS. Interobserver agreement, expressed as kappa, was 0.26 for spiculated margins, 0.60 for air bronchograms, 0.56 for rim enhancement, and 0.80 for ringlike peripheral high iodine concentration. Pulmonary metastases, compared with primary lung cancers, exhibited significantly higher frequency of ringlike peripheral high iodine concentration (52% vs 19%; p = .004) but no significant difference in frequency of spiculated margins (49% vs 32%; p = .17), air bronchograms (36% vs 51%; p = .24), or rim enhancement (4% vs 4%; p > .99). Sensitivity and specificity for diagnosing pulmonary metastasis were 68% and 49% for absence of spiculated margins, 64% and 51% for absence of air bronchograms, 4% and 96% for presence of rim enhancement, and 52% and 81% for presence of ringlike peripheral high iodine concentration. In multivariable analysis including smoking history, lesion diameter, multiple resected lesions, and ringlike peripheral high iodine concentration, the only independent significant predictor of pulmonary metastasis was ringlike peripheral high iodine concentration (OR, 7.81 [95% CI, 2.28-29.60); p = .001). CONCLUSION. Ringlike peripheral high iodine concentration had excellent interobserver agreement and high specificity (albeit poor sensitivity) for differentiating pulmonary metastasis from primary lung cancer and was independently predictive of pulmonary metastasis. CLINICAL IMPACT. Ringlike peripheral high iodine concentration could help guide management of patients with known cancer and an indeterminate solitary nodule.

Outcomes of lung oligometastasis in pancreatic cancer.

OBJECTIVE: Pancreatic cancer with lung oligometastasis may have favourable overall survival. The aim of this study was to evaluate outcomes of pancreatic cancer with lung oligometastases including both synchronous and metachronous metastases. METHODS: Consecutive pancreatic cancer patients with lung metastasis treated at our institution between February 2015 and December 2021 were identified from our prospectively maintained database. Clinical characteristics and outcomes were compared and analysed according to the extent of lung metastases. Predictors for overall survival were analysed using the Cox proportional hazards model. RESULTS: A totoal of 171 patients were included (oligometastasis/polymetastasis/multi-organ metastasis: 34/50/87). Patients with oligometastases were more likely to undergo surgical resection (41% vs. 0% vs. 2%) and showed a longer median overall survival (41.3 vs. 17.6 vs. 13.1 months) compared with those with other types of metastases. Oligometastasis (hazard ratio, 0.43; 95% confidence interval, 0.24-0.76; P = 0.004) was identified as an independent factor predicting favourable overall survival in patients with lung-only metastasis. Disease status (synchronous vs. metachronous) was not associated with survival in patients with oligometastasis (29.4 vs. 41.3 months, P = 0.527) and polymetastasis (17.9 vs. 16.7 months, P = 0.545). Selected patients who underwent surgical resection showed a median overall survival of 52.7 months. CONCLUSIONS: Patients with lung oligometastases presented a favourable prognosis. Surgical resection in selected patients was associated with a long median overall survival.

Initial perioperative outcomes of robot-assisted thoracoscopic lobectomy using a confronting setting.

PURPOSE: Most robot-assisted thoracoscopic surgery (RATS) is performed from the vertical view. This study evaluates the initial outcomes of our novel confronting RATS technique, in which the patient was viewed horizontally, as in open thoracotomy. METHODS: We reviewed data on patients who underwent thoracoscopic lobectomy between January, 2019 and April, 2022. Perioperative outcomes were compared between RATS and video-assisted thoracoscopic surgery (VATS), using propensity-score matching. RESULTS: RATS and VATS were performed for 83 and 571 patients, respectively. After propensity-score matching, data on 81 patients from each of the two groups were retrieved. The operative time was significantly longer for RATS than for VATS (199 ± 44 min vs. 173 ± 37 min, p < 0.001). There was no mortality or conversion to thoracotomy in either of the groups. The rates of overall complications and prolonged air leak did not differ significantly between the groups. The serum creatine phosphokinase level on postoperative day 4 was higher after RATS than after VATS. The number of resected lymph nodes and the rates of nodal upstaging did not differ significantly between the groups. CONCLUSION: The initial perioperative outcomes of RATS using the confronting settings were comparable to those of VATS.

Intracranial Neurofeedback Modulating Neural Activity in the Mesial Temporal Lobe During Memory Encoding: A Pilot Study.

Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent at least five sessions of memory NF training to increase the theta power in the MTL. There was an increase in theta power and a decrease in fast beta and gamma powers in one of the patients in the late stage of memory NF sessions. NF signals were not correlated with memory function. Despite its limitations as a pilot study, to our best knowledge, this study is the first to report that intracranial NF may modulate neural activity in the MTL, which is involved in memory encoding. The findings provide important insights into the future development of NF systems for the artificial reorganization of memory functions.

Impact of postoperative complications on the long-term outcome in lung cancer surgery.

PURPOSE: Postoperative complications have a significant impact on perioperative outcomes; however, their association with the long-term prognosis remains unclear. We evaluated the impact of postoperative complications on the long-term outcomes after curative surgery in lung cancer patients. METHODS: This study included 1129 patients with primary lung cancer who underwent lobectomy between April 2011 and March 2017. Univariate and multivariate analyses were performed to assess the association of postoperative complications with the overall and recurrence-free survival. RESULTS: Postoperative complications were observed in 147 (13.0%) patients over a median follow-up period of 5-years. Compared to patients without complications, those with complications showed had worse long-term outcomes, including the 5-year overall survival (75.3% vs. 86.1%, p < 0.001) and 5-year recurrence-free survival (64.2% vs. 74.4%, p = 0.004). A multivariate analysis revealed that the incidence of postoperative complications was significantly associated with the overall survival (hazard ratio = 1.665, p = 0.006) and recurrence-free survival (hazard ratio = 1.416, p = 0.025) in all patients. The prognostic influence was greater in patients with pathological stages II and III cancer (overall survival: hazard ratio = 2.019, p = 0.005; recurrence-free survival: hazard ratio = 1.90, p = 0.001) than in those with pathological stage I cancer. CONCLUSION: Postoperative complications are independent predictors of the overall and recurrence-free survival in lung cancer patients, especially advanced-stage cancer patients.

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.

Survival of Octogenarians with Early-Stage Non-small Cell Lung Cancer is Comparable Between Wedge Resection and Lobectomy/Segmentectomy: JACS1303.

BACKGROUND: Anatomic resection with lymph node dissection or sampling is the standard treatment for early non-small cell lung cancer (NSCLC), and wedge resection is an option for compromised patients. This study aimed to determine whether wedge resection can provide comparable prognoses for elderly patients with NSCLC. METHODS: The study analyzed the clinicopathologic findings and surgical outcomes during a median follow-up period of 39.6 months for 156 patients with solid dominant (consolidation-to-tumor ratio > 0.5) small (whole tumor size ≤ 2 cm) NSCLC among 892 patients 80 years of age or older with medically operable lung cancer between April 2015 and December 2016. RESULTS: The 3-year overall survival (OS) rates after wedge resection and after segmentectomy plus lobectomy did not differ significantly (86.5 %; 95 % confidence interval [CI], 74.6-93.0 % vs 83.7 % 95 % CI, 74.0-90.0 %; P = 0.92). Multivariable Cox regression analysis of OS with propensity scores showed that the surgical procedure was not an independent prognostic predictor (hazard ratio [HR], 0.84; 95 % CI, 0.39-1.8; P = 0.64). The 3-year OS rates were slightly better after wedge resection for 97 patients who could tolerate lobectomy than after segmentectomy plus lobectomy (89.4 %; 95 % CI, 73.8-95.9 % vs 75.8 %; 95 % CI, 62.0-85.2 %; P = 0.14). The cumulative incidence of other causes for death was marginally higher after segmentectomy plus lobectomy than after wedge resection (P = 0.079). CONCLUSIONS: Wedge resection might be equivalent to lobectomy or segmentectomy for selected patients 80 years of age or older with early-stage NSCLC who can tolerate lobectomy.

Comparison of local therapy in patients with lung oligo-recurrence of non-small-cell lung cancer.

BACKGROUND AND OBJECTIVES: The effectiveness of local therapy has been reported in non-small-cell lung cancer (NSCLC) patients with oligo-recurrence. However, there is still no clear consensus on the choice of local therapy. We aimed to examine the choice of local therapy in NSCLC patients with lung oligo-recurrence. METHODS: Among 1760 consecutive NSCLC patients who underwent complete resection between 1990 and 2008, 535 patients developed recurrence. Lung oligo-recurrence was defined as 1-5 metachronous recurrences limited to the lungs only; such recurrence was found in 97 patients. We examined the differences in the prognosis of each therapy for these patients. RESULTS: The 5-year postrecurrence survival (PRS) rates in patients who underwent local therapy (n = 54) and those who did not (n = 43) were 55.6% and 31.1%, respectively; it was significantly higher in patients who underwent local therapy (p = 0.004). Among 47 patients who underwent resection or radiation therapy, the 5-year PRS rates were 61.5% and 47.6% (p = 0.258), and the 5-year postrecurrence progression-free survival rates were 30.3% and 24.7% (p = 0.665), respectively, without any significant difference. CONCLUSIONS: Patients with lung oligo-recurrence should consider local therapy individually, depending on their general condition.

Permissible Outcomes of Lobe-Specific Lymph Node Dissection for Elevated Carcinoembryonic Antigen in Non-Small Cell Lung Cancer.

Background and Objectives: Lobe-specific nodal dissection (L-SND) is currently acceptable for the dissection of early-stage non-small cell lung cancer (NSCLC) but not for cancers of more advanced clinical stages. We aimed to assess the efficacy of L-SND, compared to systemic nodal dissection (SND). Materials and Methods: We retrospectively collected the clinical data of patients with carcinoembryonic antigen (CEA) abnormality who underwent complete resection of NSCLC via lobectomy or more in addition to either SND or L-SND at two cancer-specific institutions from January 2006 to December 2017. Results: A total of 799 patients, including 265 patients who underwent SND and 534 patients who underwent L-SND, were included. On multivariate analysis, thoracotomy, more than lobectomy, cN1-2, advanced pathological stage, adjuvant treatment, and EGFR or ALK were strongly associated with SND. No significant differences were found in overall survival, disease-free survival, and overtime survival after propensity adjustment (p = 0.09, p = 0.11, and p = 0.50, respectively). There were no significant differences in local (p = 0.16), regional (p = 0.72), or distant (p = 0.39) tumor recurrence between the two groups. Conclusions: SND did not improve the prognosis of NSCLC patients with CEA abnormality. Complete pulmonary resection via L-SND seems useful for NSCLC patients with CEA abnormality.

Outcomes after thoracoscopic surgery in octogenarian patients with clinical N0 non-small-cell lung cancer.

OBJECTIVE: The number of surgeries for elderly patients with lung cancer is increasing. In our institute, thoracoscopic lobectomy and hilar lymph node dissection are the standard procedure for octogenarian patients with clinical N0 non-small-cell lung cancer. The aim of this study was to determine the outcome of our strategy for octogenarian patients. METHODS: Seventy octogenarian patients with clinical N0 non-small-cell lung cancer who underwent surgery were enrolled (O group). As a control group, 205 septuagenarian patients were also enrolled (S group). We compared several clinicopathological factors and outcomes. RESULTS: The median age of the O group was 82. There was no significant difference in the comorbidity ratio between the two groups. The 5-year overall survival ratio for the O group (72.8%) was significantly worse than that for the S group (88.3%). However, multivariate analysis proved age was not an independent predictor of outcome. The rates of recurrences involving ipsilateral mediastinal lymph nodes were equal in the two groups. After propensity score matching, clinical T1 patients were dominant (85%) in two matched group and no statistically significant differences were observed in the 5-year overall survival between the two groups. CONCLUSIONS: Our strategy for octogenarian patients with non-small-cell lung cancer, including omission of mediastinal lymph node dissection, was determined to be feasible, in particularly with cT1N0 disease.

Recent fluorescence imaging technology applications of indocyanine green in general thoracic surgery.

Thoracic surgeons perform a wide variety of cancer operations, which are often associated with high morbidity and mortality. Thus, thoracic surgery involves many special challenges that require innovative solutions. The increased utilization of minimally invasive practices, poor overall cancer survival, and significant morbidity of critical operations remain key obstacles to overcome. Fluorescence imaging technology (FIT), involving the implementation of fluorescent dyes and imaging systems, is currently used as an adjunct for general thoracic surgery in many situations and includes sentinel lymph node mapping, pulmonary intersegmental plane identification, pulmonary nodule identification, pulmonary bullous lesion detection, evaluation of the anastomotic perfusion after tracheal surgery, and thoracic duct imaging for postoperative chylothorax. This technology enhances the surgeon's ability to perform operations, and has specific advantages. We review some of the key studies that demonstrate the applications of FIT in the field of general thoracic surgery, focusing on the use of indocyanine green.

Biocompatible and flexible paper-based metal electrode for potentiometric wearable wireless biosensing.

A paper-based electrode is a very attractive component for a disposable, nontoxic, and flexible biosensor. In particular, wearable biosensors, which have recently been attracting interest, not only require these characteristics of paper-based electrodes but must also be able to detect various ions and biomolecules in biological fluids. In this paper, we demonstrate the detection ability of paper-based metal electrodes for wearable biosensors as part of a wireless potentiometric measurement system, focusing on the detection of pH and sodium ions. The paper-based metal electrodes were obtained by simply coating a silicone-rubber-coated paper sheet with a Au (/Cr) thin film by sputtering then modifying it with different functional membranes such as an oxide membrane (Ta2O5) and a fluoropolysilicone (FPS)-based Na+-sensitive membrane, corresponding to the targeted ions. Satisfactory and stable detection sensitivities of the modified paper-based Au electrodes were obtained over several weeks even when they were bent to a radius of curvature in the range of 6.5 to 25 mm, assuming use in a flexible body patch biosensor. Moreover, the Na+ concentration in a sweat sample was evaluated using the paper-based Au electrode with the FPS-based Na+-sensitive membrane in a wireless and real-time manner while the electrode was bent. Thus, owing to their complex mesh structure, flexible paper sheets should be suitable for use as potentiometric electrodes for wearable wireless biosensors.

Efficiency of thoracoscopic palpation in localizing small pulmonary nodules.

PURPOSE: The thoracoscopic localization of small and deep pulmonary nodules can be challenging. We conducted this study to evaluate the efficiency of thoracoscopic palpation in tumor detection. METHODS: The subjects of this study were 229 patients with a collective 267 indeterminate pulmonary nodules ≤ 15 mm in diameter, in the outer third of the lung field. The nodules were localized by palpation using the forefinger or a metal suction probe. Based on the distance from the pleura-to-tumor size ratio (D/S), the nodules were classified into group A (D/S = 0), group B (0 < D/S ≤ 1), and group C (D/S > 1). RESULTS: The median tumor diameter was 10 mm. All 267 nodules were palpable and resected with negative margins via thoracoscopic wedge resection. The majority of the deep nodules had no pleural change (11%, 86%, and 100% in groups A, B, and C, respectively; P < 0.01). The median margins were 15, 16, and 14 mm in groups A, B, and C, respectively. In four patients (1.5%) with relatively short margins (2-7 mm), an additional intraoperative wedge resection was performed. CONCLUSION: Thoracoscopic palpation was effective for tumor detection when the nodules were located in the outer third of the lung.

[Thoracoscopic Segmentectomy Using Three-dimensional Computed Tomography and Indocyanine-green Fluorescence Navigation].

BACKGROUND: We investigated the feasibility and efficacy of thoracoscopic segmentectomy using 3-dimensional computed tomography( 3D-CT) and indocyanine-green( ICG) fluorescence navigation. METHODS: ICG fluorescence-navigated thoracoscopic segmentectomy was performed in 149 patients during 2013 and 2017. Each patient underwent preoperative evaluation by thin-section enhanced CT, which provided 3-dimensional simulations of vascular and bronchial structures. During the procedure, low-dose ICG( 0.15~0.25 mg/kg) was injected systemically after the target segmental pulmonary arteries and bronchus were divided. Under near-infrared thoracoscopic guidance, an intersegmental plane was clearly observed as a border between dark target region and bright residual region. The ICG fluorescent line was marked by electrocautery, followed by division of lung parenchyma along the line by endoscopic staples. RESULTS: An intersegmental line was visible in 98% of patients by ICG fluorescence navigation. No ICG-related adverse events occurred. No operative mortality was observed and morbidity rate was 8.7%. The 5-year overall survival rate and the 5-year recurrence free probability of 101 patients with primary lung cancer were 92% and 98%, respectively. Local recurrence at the resected site occurred in no patient with lung cancer and 1 patient with pulmonary metastasis. CONCLUSION: Thoracoscopic segmentectomy using 3D-CT and ICG fluorescence navigation is a useful therapeutic option.

Histology is a Prognostic Indicator After Pulmonary Metastasectomy from Renal Cell Carcinoma.

OBJECTIVES: There are only a few detailed reports concerning the prognosticators following surgical resection of pulmonary metastases (PMs) from renal cell carcinoma (RCC). We investigated the prognosis of patients with RCC PMs undergoing pulmonary metastasectomy and identified prognostic factors in a multi-institutional retrospective study. METHODS: We retrospectively evaluated 84 patients who underwent resection of PMs from RCC between 1993 and 2014. We assessed the clinicopathological characteristics, focusing on the histological findings of PMs. We classified the histology into three types: pure clear cell carcinoma (N = 68), clear cell carcinoma combined with other histology type (N = 8), and non-clear cell carcinoma (N = 8). We examined the relationship between these histological types and the prognosis of patients with PMs from RCC. RESULTS: Complete resection was achieved in 78 patients (93%). The 5-year overall survival rate after metastasectomy was 59.7%. In multivariate analysis, three factors were found to be independent favorable prognostic factors of overall survival after lung metastasectomy [tumor size <2 cm, hazard ratio (HR) = 0.31, 95% confidence interval (CI) 0.13-0.78, P = 0.012; clear cell type, HR = 0.37, 95% CI 0.16-0.83, P = 0.025; and complete resection, HR = 0.27, 95% CI 0.10-0.78, P = 0.015]. CONCLUSIONS: This study indicates that a histological finding of the clear cell type is a significant favorable prognostic factor in addition to complete resection and a tumor size <2 cm. Histological evaluation of PM lesions is important for predicting survival after metastasectomy.

High expression of programmed cell death 1 ligand 1 in lung adenocarcinoma is a poor prognostic factor particularly in smokers and wild-type epidermal growth-factor receptor cases.

A clinical implication of programmed cell death 1 ligand 1 (PD-L1) expression in lung adenocarcinoma has not been well established. We evaluated PD-L1 expression immunohistochemically on 296 surgically resected lung adenocarcinomas to investigate a clinical implication of PD-L1 expression especially in terms of smoking history and epidermal growth-factor receptor (EGFR) mutation status. Patients were classified into high- and low-PD-L1 expression groups. The high-expression group (n = 107) showed a significantly higher proportion of smokers and poor differentiation compared with the low-expression group (n = 189). Survival analysis showed that the prognosis of the high-expression group was worse in overall survival than that of the low-expression group (3-year overall survival 85 vs. 94%, P = 0.005). Stratified survival analyses showed that the prognoses of the high-expression group were worse than those of the low-expression group in both strata of smokers and wild-type EGFR (P = 0.009 and P = 0.007, respectively). We found that high PD-L1 expression was a poor prognostic factor in the smokers or the patients with wild-type EGFR, whereas it was not the case in those who never smoked or those with EGFR mutation, implying the importance of adenocarcinoma driver mutations and etiology.

Prognostic impact of bulky swollen lymph nodes in cN1 non-small cell lung cancer patients.

OBJECTIVE: The aim of this study was to analyze clinicopathological backgrounds and prognosis of clinical N1 non-small cell lung cancer and clarify the difference between bulky and non-bulky cN1 diseases. METHODS: We reviewed 110 patients with completely resected cN1 non-small cell lung cancer and examined the prognostic impact of lymph node size. We classified the swollen lymph nodes into two groups based on their size on chest computed tomography: short-axis diameter ≥20 mm (=bulky group) or <20 mm (=non-bulky group). RESULTS: The bulky group consisted of 10 patients, and the non-bulky group comprised 100 patients. There was no significant difference in the upstaging rate to pathological N2 between the bulky and non-bulky groups (31% vs. 30%; P = 0.63). The 5-year recurrence-free survival rate and 5-year overall survival rate of both groups did not differ significantly (P = 0.36, P = 0.30, respectively). Our results suggested the possibility that the size of the swollen lymph nodes had no impact on the prognosis in cN1 non-small cell lung cancer patients. In comparison of surgical procedure, pneumonectomy was performed in the bulky group more frequently than the non-bulky group (70% vs. 19%; P < 0.01). CONCLUSIONS: Bulky cN1 disease was not different from non-bulky disease in the prognosis and the upstaging rate to pN2. Curative resection should be indicated to resectable bulky cN1 disease as with non-bulky disease, with careful pre-operative evaluation and preparation considering the possibility of pneumonectomy.

Chromosome interior observation by focused ion beam/scanning electron microscopy (FIB/SEM) using ionic liquid technique.

Attempts to elucidate chromosome structure have long remained elusive. Electron microscopy is useful for chromosome structure research because of its high resolution and magnification. However, biological samples such as chromosomes need to be subjected to various preparation steps, including dehydration, drying, and metal/carbon coating, which may induce shrinkage and artifacts. The ionic liquid technique has recently been developed and it enables sample preparation without dehydration, drying, or coating, providing a sample that is closer to the native condition. Concurrently, focused ion beam/scanning electron microscopy (FIB/SEM) has been developed, allowing the investigation and direct analysis of chromosome interiors. In this study, we investigated chromosome interiors by FIB/SEM using plant and human chromosomes prepared by the ionic liquid technique. As a result, two types of chromosomes, with and without cavities, were visualized, both for barley and human chromosomes prepared by critical point drying. However, chromosome interiors were revealed only as a solid structure, lacking cavities, when prepared by the ionic liquid technique. Our results suggest that the existence and size of cavities depend on the preparation procedures. We conclude that combination of the ionic liquid technique and FIB/SEM is a powerful tool for chromosome study.

Laser-assisted direct roller imprinting of large-area microstructured optical surfaces.

In this study, a high-throughput fabrication method called laser-assisted direct roller imprinting (LADRI) was developed to lower the cost of nanoimprinting large-area polymer films and to address problems associated with nanoimprinting, namely, microstructural damage and precision in flatness of entire film. With LADRI, the laser directly heats the microstructured surface of the roller mold, which heats and melts the surface of a polymethyl methacrylate (PMMA) film to replicate the microstructures on the mold rapidly. In this study, the effects of laser power density, scanning speed, size of the microstructures, and contact pressure on the replication speed were investigated experimentally. The replication speed increased as the power and scanning speed increased. However, because the film required heating until it filled the entire depth of the microstructure, an appropriate replication speed was necessary. This result was supported by simulation of the temperature distribution inside the mold and the PMMA using transient heat conduction analyses. To demonstrate the applications of LADRI, two different optical surfaces were replicated: an antireflection (AR) structure with conical structures sized several hundred nanometers and a light-extraction structure with a microlens array (MLA) comprising 10 µm lenses, for display and illumination, respectively. The replication degree of the MLA was governed by the contact pressure. Polymer flow simulation indicated that the heat conduction and flow speeds of the melted PMMA surface were comparable within several tens of micrometers. In addition, the reflectivity of the AR structure decreased from 4 to 0.5%, and the light intensity of the light-extraction structure increased by a factor of 1.47.