Untethered shape-changing devices in the gastrointestinal tract.

INTRODUCTION: Advances in microfabrication, automation, and computer engineering seek to revolutionize small-scale devices and machines. Emerging trends in medicine point to smart devices that emulate the motility, biosensing abilities, and intelligence of cells and pathogens that inhabit the human body. Two important characteristics of smart medical devices are the capability to be deployed in small conduits, which necessitates being untethered, and the capacity to perform mechanized functions, which requires autonomous shape-changing. AREAS COVERED: We motivate the need for untethered shape-changing devices in the gastrointestinal tract for drug delivery, diagnosis, and targeted treatment. We survey existing structures and devices designed and utilized across length scales from the macro to the sub-millimeter. These devices range from triggerable pre-stressed thin film microgrippers and spring-loaded devices to shape-memory and differentially swelling structures. EXPERT OPINION: Recent studies demonstrate that when fully enabled, tether-free and shape-changing devices, especially at sub-mm scales, could significantly advance the diagnosis and treatment of GI diseases ranging from cancer and inflammatory bowel disease (IBD) to irritable bowel syndrome (IBS) by improving treatment efficacy, reducing costs, and increasing medication compliance. We discuss the challenges and possibilities associated with ensuring safe, reliable, and autonomous operation of these smart devices.

Intractable chylous leak after radical esophagectomy treated with radiotherapy.

Postoperative chylous leak after esophagectomy is a rare but potentially life-threatening complication that results in hypovolemia, electrolyte imbalance, malnutrition, and immunologic deficiency. However, the management of postoperative chylous leak remains controversial. Following a diagnosis of esophageal cancer, a 64-year-old man was treated by video-assisted thoracoscopic esophagectomy, laparoscopic gastric tube formation, prophylactically thoracic duct ligation, and reconstruction with esophagogastrostomy at the neck level. Massive postoperative drainage from the thorax and abdomen did not initially meet the diagnostic criteria for chylothorax, which was ultimately diagnosed 3 weeks after the operation. Despite various treatments including total parenteral nutrition, octreotide and midodrine, reoperation (thoracic duct ligation and mechanical pleurodesis), and thoracic duct embolization, the chylous leak persisted. Finally, low-dose radiation therapy was administered with a daily dose of 2 Gy and completed at a total dose of 14 Gy. After this, the amount of pleural effusion gradually decreased over 2 weeks, and the last drainage tube was removed. The patient was alive and well at 60 months postoperatively. Herein, we describe a patient with intractable chylous leak after esophagectomy, which persisted despite conservative treatment, thoracic duct ligation, and embolization, but was finally successfully treated with radiotherapy.

Large mesenchymal cystic and chondroid pulmonary hamartoma mimicking lung cancer: Case report.

Pulmonary hamartoma is the most commonly resected benign neoplasm of lung. The mesenchymal cystic subtype is a rare and often bilaterally occurring variant composed of multiple cysts and nodules. Herein, we present an asymptomatic 70-year-old woman with a large and mostly cystic growth of right hilar region. Computed tomography of the chest and fluorodeoxyglucose positron emission tomography/computed tomography imaging traced its origins to right middle lobe. Overall features suggested primary lung cancer or perhaps other cystic lung disease.Because transbronchial lung biopsy failed to establish a histologic diagnosis, right middle lobectomy was undertaken by video-assisted thoracoscopic surgery. The gross surgical specimen harbored a single and sizeable (8.0 × 4.0 cm) cystic lesion containing multiple yellow-white nodules. A diagnosis of mesenchymal cystic and chondroid hamartoma was ultimately rendered. This particular case is noteworthy, given the initial clinical resemblance to primary lung cancer.

Left anterior descending artery dissection with retrograde aortic dissection during percutaneous coronary intervention: a case report.

Retrograde catheter-induced coronary artery dissection during percutaneous coronary intervention is an exceedingly rare occurrence, and the likelihood of it extending into the aorta is even more uncommon. Typically, surgical treatment involves aortic root replacement combined with coronary artery bypass grafting. However, in this particular case, a meticulous approach was employed. By carefully guiding wires into the true lumens and placing stents in the proximal left main and left anterior descending arteries, the immediate complications were averted by obstructing the retrograde flow in the false lumen. Subsequently, an off-pump coronary artery bypass was performed using the left internal mammary artery to the left anterior descending artery, without the need to manipulate the aorta. This approach resulted in a short operation time and the absence of any other complications.

Natural History of Contralateral Bullae/Blebs After Ipsilateral Video-Assisted Thoracoscopic Surgery for Primary Spontaneous Pneumothorax: A Retrospective Cohort Study.

BACKGROUND: Contralateral bullae/blebs are frequently found in patients who are scheduled to undergo ipsilateral video-assisted thoracoscopic surgery (VATS) for primary spontaneous pneumothorax (PSP). RESEARCH QUESTION: Should visible contralateral bullae/blebs be simultaneously resected when ipsilateral VATS bullectomy is performed? STUDY DESIGN AND METHODS: In this single-center, retrospective cohort study, we included patients aged ≤ 30 years who underwent ipsilateral VATS for PSP from April 2009 to December 2019. Electronic medical records, radiograph images, and preoperative high-resolution CT images were reviewed. The primary end point was recurrence-free survival (no contralateral pneumothorax) after discharge of ipsilateral VATS for PSP, determined via Kaplan-Meier analysis. Recurrence was compared between the group with and that without contralateral bullae/blebs by using the log-rank test. A multivariable Cox proportional hazards model was constructed to investigate risk factors for contralateral pneumothorax. RESULTS: Among 567 patients, contralateral pneumothorax occurred in 86 of them after ipsilateral VATS (15.2%) during a median follow-up period of 51.3 (interquartile range, 67.2) months. The 1-, 5-, and 10-year recurrence-free survival rates were 92.2%, 83.7%, and 79.9%, respectively. Contralateral recurrence was higher in the group with (82/455, 18.0%) than in that without (4/112, 3.6%) contralateral bullae/blebs (P < .001). Age (hazard ratio [HR], 0.701; 95% CI, 0.629-0.780; P < .001), current smoking (HR, 2.106; 95% CI, 1.158-3.831; P = .015), and the presence of bullae/blebs (increasing with size, HR, 4.818-8.980; all P < .05) were independent risk factors for contralateral pneumothorax. The annual rates of contralateral pneumothorax in the group with (4.0%) and in that without (0.7%) contralateral bullae/blebs declined over time. INTERPRETATION: Although contralateral bullae/blebs were common in patients who underwent ipsilateral VATS for PSP and were statistically significantly associated with future pneumothorax, the annual rate of pneumothorax was 4.0% in such patients, and it decreased over time. Therefore, a conservative approach on unruptured contralateral bullae/blebs is recommended.

Uniportal video-assisted thoracoscopic surgery (VATS) for the treatment of early-stage lung cancer with whole pleural adhesion.

Background: Uniportal video-assisted thoracoscopic surgery (VATS) is considered a challenging procedure in cases of lung cancer where the entire pleura and lung are attached (whole pleural adhesion). The purpose of this study was to evaluate the surgical results of uniportal VATS for the treatment of lung cancer with whole pleural adhesion. Methods: For all patients who underwent VATS lung cancer surgery at a single hospital in Korea, multiportal VATS was performed before 2017 and uniportal VATS was performed after January 2017 by the same surgeons. The surgical results of multiportal VATS and uniportal VATS for the treatment of lung cancer with whole pleural adhesion were compared retrospectively. Results: There were 16 eligible uniportal VATS cases and 57 multiportal VATS cases. There were no significant differences of clinicopathologic characteristics between the two groups. There were 5 conversions to open thoracotomy in the multiportal VATS group and no conversion to open thoracotomy in the uniportal group (P=0.579). The perioperative and postoperative outcomes were not different between the two groups. There was no mortality in all patients. For patients undergoing VATS lobectomy, the perioperative and postoperative outcomes were similar after uniportal and multiportal VATS lobectomy. For all patients, the 3-year recurrence-free survival (RFS) was 80.0% after uniportal VATS and 79.5% after multiportal VATS (P=0.951) and for patients with stage I non-small cell lung cancer (NSCLC), the 3-year RFS after uniportal VATS was 91.7% and the 3-year RFS after multiportal VATS was 89.3% (P=0.999). Uniportal VATS was not a significant risk factor for recurrence in the multivariate analysis. Conclusions: Uniportal VATS was not inferior to multiportal VATS in surgical outcome or short-term prognosis in resection of lung cancer with whole pleural adhesion. Whole pleural adhesion is not a contraindication to uniportal VATS, which has been safe and feasible in cases of lung cancer with whole pleural adhesion.

Van der Waals Heterostructure of Hexagonal Boron Nitride with an AlGaN/GaN Epitaxial Wafer for High-Performance Radio Frequency Applications.

While two-dimensional (2D) hexagonal boron nitride (h-BN) is emerging as an atomically thin and dangling bond-free insulating layer for next-generation electronics and optoelectronics, its practical implementation into miniaturized integrated circuits has been significantly limited due to difficulties in large-scale growth directly on epitaxial semiconductor wafers. Herein, the realization of a wafer-scale h-BN van der Waals heterostructure with a 2 in. AlGaN/GaN high-electron mobility transistor (HEMT) wafer using metal-organic chemical vapor deposition is presented. The combination of state-of-the-art microscopic and spectroscopic analyses and theoretical calculations reveals that the heterointerface between ∼2.5 nm-thick h-BN and AlGaN layers is atomically sharp and exhibits a very weak van der Waals interaction without formation of a ternary or quaternary alloy that can induce undesired degradation of device performance. The fabricated AlGaN/GaN HEMT with h-BN shows very promising performance including a cutoff frequency (fT) and maximum oscillation frequency (fMAX) as high as 28 and 88 GHz, respectively, enabled by an effective passivation of surface defects on the HEMT wafer to deliver accurate information with minimized power loss. These findings pave the way for practical implementation of 2D materials integrated with conventional microelectronic devices and the realization of future all-2D electronics.

Loss of BubR1 acetylation provokes replication stress and leads to complex chromosomal rearrangements.

Accurate chromosomal segregation during mitosis is regulated by the spindle assembly checkpoint (SAC). SAC failure results in aneuploidy, a hallmark of cancer. However, many studies have suggested that aneuploidy alone is not oncogenic. We have reported that BubR1 acetylation deficiency in mice (K243R/+) caused spontaneous tumorigenesis via weakened SAC signaling and unstable chromosome-spindle attachment, resulting in massive chromosomal mis-segregation. In addition to aneuploidy, cells derived from K243R/+ mice exhibited moderate genetic instability and chromosomal translocation. Here, we investigated how the loss of BubR1 acetylation led to genetic instability and chromosomal rearrangement. To rescue all chromosomal abnormalities generated by the loss of BubR1 acetylation during development, K243R/+ mice were crossed with p53-deficient mice. Genome-wide sequencing and spectral karyotyping of tumors derived from these double-mutant mice revealed that BubR1 acetylation deficiency was associated with complex chromosomal rearrangements, including Robertsonian-like whole-arm translocations. By analyzing the telomeres and centromeres in metaphase chromosome spreads, we found that BubR1 acetylation deficiency increased the collapse of stalled replication forks, commonly referred to as replication stress, and led to DNA damage and chromosomal rearrangements. BubR1 mutations that are critical in interacting with PCAF acetyltransferase and acetylating K250, L249F and A251P, were found from human cancers. Furthermore, a subset of human cancer cells exhibiting whole-arm translocation also displayed defects in BubR1 acetylation, supporting that defects in BubR1 acetylation in mitosis contributes to tumorigenesis. Collectively, loss of BubR1 acetylation provokes replication stress, particularly at the telomeres, leading to genetic instability and chromosomal rearrangement.

The prognosis of stage I non-small cell lung cancer with visceral pleural invasion and whole pleural adhesion after video-assisted thoracoscopic lobectomy: A single center retrospective study.

BACKGROUND: In cases of peripheral lung cancer with visceral pleural invasion and severe pleural adhesion, the question arises as to whether video-assisted thoracoscopic surgery (VATS) is a safe operation. The purpose of this study was to evaluate whether whole pleural adhesion is a risk factor for recurrence of cancer when performing VATS lobectomy for stage I non-small cell lung cancer (NSCLC) with visceral pleural invasion. METHODS: From 2010 to 2018, 123 consecutive patients who were diagnosed as stage I NSCLC with visceral pleural invasion and who underwent VATS lobectomy, were reviewed retrospectively. Those patients with partial pleural adhesion were excluded. The prognoses of the patients in the whole pleural adhesion group were compared with those of the non-adhesion group. RESULTS: The clinicopathological characteristics were not found to differ between the two groups, with the exception of age. The mean age of the whole pleural adhesion group was found to be greater than that of the non-adhesion group (70.6 vs. 64.4, P=0.002). The 5-year recurrence-free survival rates for the whole pleural adhesion group and the non-adhesion group were 64.8% and 70.9% respectively, and they were not statistically different (P=0.545). In multivariate analysis, the extent of lymph node dissection (hazard ratio =13.854, P=0.023) was a significant risk factor for recurrence. Whole pleural adhesion was not a risk factor for recurrence. CONCLUSIONS: Whole pleural adhesion was not a risk factor for recurrence after VATS lobectomy in stage I NSCLC with visceral pleural invasion. However, the extent of lymph node dissection was identified as an important prognostic factor.

Prognosis of wide wedge resection in patients with stage IA1 and IA2 lung adenocarcinoma with total tumor size including the lepidic component greater than 2 cm: a single center retrospective study.

BACKGROUND: Stage I lung adenocarcinoma with a lepidic component has a good prognosis after sublobar resection. The purpose of this study is to evaluate the prognosis of wide wedge resection in patients diagnosed with stage IA1 and IA2 lung adenocarcinoma (based on the eighth edition of the TNM staging system) in which the total tumor size, including the lepidic component, is more than 2 cm. METHODS: From 2010 to 2018, 180 consecutive patients were diagnosed with stage IA1 and IA2 lung adenocarcinoma with a total tumor size (including the lepidic component) of more than 2 cm, and they underwent wide wedge resection or lobectomy at a hospital in Korea. The patients were determined as stage IA1 or stage IA2, and their clinicopathological characteristics and prognosis were compared between the wedge resection group and the lobectomy group. RESULTS: The clinicopathological characteristics were not statistically different between the wedge resection group and the lobectomy group. There were no recurrences and cancer-related deaths during the follow-up period for patients with stage IA1 lung adenocarcinoma in the wedge resection group and the lobectomy group. However, the 5-year recurrence-free survival rates of the wedge resection group and the lobectomy group were statistically different (73.9% and 90.8%, respectively; P=0.031) in stage IA2 lung adenocarcinoma. In a multivariate analysis of risk factors for recurrence, wedge resection [hazard ratio (HR) =15.883; P=0.026] and lymphovascular invasion (HR =13.854; P=0.023) were significant risk factors for recurrence in patients with stage IA2 lung adenocarcinoma. CONCLUSIONS: In the cases of lung adenocarcinoma with a total tumor size (including the lepidic component) of more than 2 cm, a good prognosis can be expected with wide wedge resection in stage IA1, but not an appropriate surgical choice for the cases in stage IA2.

Risk Factors for Occult Lymph Node Metastasis in Peripheral Non-Small Cell Lung Cancer with Invasive Component Size 3 cm or Less.

BACKGROUND: In the seventh edition TNM staging system for lung cancer, a high maximum standardized uptake value (SUVmax) on positron emission tomography was regarded as a risk factor for occult lymph node metastasis in clinical T1N0 non-small cell lung cancer (NSCLC). However, in the eighth edition TNM classification, tumors are classified according to the size of the invasive component only, and those with invasive component size ≤3 cm are diagnosed as stage T1. The aim of this study was to reassess the risk factors for occult lymph node metastasis under the eighth edition TNM classification for lung cancer. METHODS: From 2010 to 2017, 553 patients with clinical N0 peripheral NSCLC with invasive component size ≤3 cm underwent anatomical lobectomy with systematic lymph node dissection. We analyzed these cases retrospectively to identify risk factors for postoperative nodal upstaging. RESULTS: Among 553 study patients, 54 (9.8%) had nodal upstaging after surgery. In multivariate analysis adopting the eighth edition TNM classification for lung cancer, serum carcinoembryonic antigen (CEA) level (hazard ratio [HR] = 1.113, p = 0.002), invasive component size (HR = 2.398, p = 0.004), visceral pleural invasion (HR = 2.901, p = 0.005), and lymphatic invasion (HR = 9.336, p < 0.001) were significant risk factors for nodal upstaging, but SUVmax was not. CONCLUSION: SUVmax is not a predictor of nodal upstaging in clinical N0 peripheral NSCLC with invasive component size ≤3 cm under the eighth edition TNM classification for lung cancer. Significant risk factors of occult lymph node metastasis are serum CEA level, tumor invasive component size, visceral pleural invasion, and lymphatic invasion.

The prognosis of small-sized non-small cell lung cancer with visceral pleural invasion after sublobar resection.

BACKGROUND: Sublobar resection is sometimes performed as a surgical treatment for small peripheral tumors. However, there is a question about whether sublobar resection is adequate treatment when visceral pleural invasion is diagnosed postoperatively. The purpose of this study was to evaluate the prognosis of patients with small-sized stage IB non-small cell lung cancer (NSCLC) after sublobar resection. METHODS: From January 2010 to December 2018, 227 consecutive patients with eighth edition TNM stage IB NSCLC (per the joint staging system of the International Association for the Study of Lung Cancer and the American Joint Committee on Cancer) underwent curative surgery at a single center. Those patients were reviewed retrospectively. The clinicopathological characteristics and prognosis were compared between the sublobar resection group and the lobectomy group. The sublobar resection group included only small-sized (invasive component size ≤2 cm) NSCLC. RESULTS: In all study patients, clinicopathological characteristics between the sublobar resection and lobectomy groups were not different except in maximum standardized uptake value (SUVmax) and invasive component size. The 5-year recurrence-free survival (RFS) rate was 80.7% after sublobar resection and 73.4% after lobectomy (P=0.349). The 5-year overall survival (OS) rate was 87.3% after sublobar resection and 84.8% after lobectomy (P=0.503). In patients with small-sized NSCLC, the clinicopathological characteristics were not different between the sublobar resection group and the lobectomy group. The 5-year RFS rate was 80.7% after sublobar resection and 72.3% after lobectomy (P=0.417). The 5-year OS rate was 87.3% after sublobar resection and 91.2% after lobectomy (P=0.956). Sublobar resection was not a risk factor for recurrence in the multivariate analysis. CONCLUSIONS: The prognosis of sublobar resection in patients with small-sized stage IB NSCLC was comparable with lobectomy. Thus, additional completion lobectomy may not be essential in this setting, despite postoperative upstaging from T1 to T2a.

Atypical Thymic Carcinoid in a Patient with Zollinger-Ellison Syndrome.

Atypical thymic carcinoid is an extremely rare tumor with a poor prognosis. In addition to its known association with multiple endocrine neoplasia type 1, its hallmark characteristics include local invasion and early distant metastasis. In this report, we share our experience treating atypical thymic carcinoid in a patient with Zollinger-Ellison syndrome.

Prognostic Factors in Stage IIB Non-Small Cell Lung Cancer according to the 8th Edition of TNM Staging System.

BACKGROUND: The purposes of this study were to evaluate the appropriateness of the stage migration of stage IIA non-small cell lung cancer (NSCLC) in the seventh edition of the tumor, node, and metastasis classification for lung cancer to stage IIB lung cancer in the eighth edition, and to identify prognostic factors in patients with eighth-edition stage IIB disease. METHODS: Patients with eighth-edition stage IIB disease were subclassified into those with seventh-edition stage IIA disease and those with seventh-edition stage IIB disease, and their recurrence-free survival and disease-specific survival rates were compared. Risk factors for recurrence after curative resection were identified in all included patients. RESULTS: Of 122 patients with eighth-edition stage IIB NSCLC, 101 (82.8%) had seventh-edition stage IIA disease and 21 (17.2%) had seventh-edition stage IIB disease. Nonsignificant differences were observed in the 5-year recurrence-free survival rate and the 5-year disease-specific survival rate between the patients with seventh-edition stage IIA disease and those with seventh-edition stage IIB disease. Visceral pleural invasion was a significant risk factor for recurrence in patients with eighth-edition stage IIB NSCLC. CONCLUSION: The stage migration from seventh-edition stage IIA NSCLC to eighth-edition stage IIB NSCLC was appropriate in terms of oncological outcomes. Visceral pleural invasion was the only prognostic factor in patients with eighth-edition stage IIB NSCLC.

Long-Term Survival after Wide Resection of Malignant Fibrous Histiocytoma of the Chest Wall.

Primary malignant fibrous histiocytoma (MFH) of the chest wall is extremely rare and is characterized by aggressive features, including a high incidence of local recurrence and distant metastasis. Surgical resection of the chest wall is the primary modality of management. However, surgical treatment is not generally recommended in patients with evidence of distant metastasis. Here, we present a case of chest wall MFH along with a schwannoma mimicking distant metastasis in the right upper arm. The patient was treated by radical en bloc resection and survived for more than 9 years without recurrence.

Prognostic factors in stage IB non-small cell lung cancer according to the 8th edition of the TNM staging system after curative resection.

BACKGROUND: Patients with stage IB non-small cell lung cancer (NSCLC) with poor prognostic factors can be treated selectively with postoperative adjuvant chemotherapy. The aim of this study was to identify the prognostic factors of stage IB NSCLC according to the new 8th edition of the tumor, node, and metastasis (TNM) staging system. METHODS: From 2005 to 2016, 211 patients who were diagnosed with stage IB NSCLC according to the 8th edition of the TNM staging system underwent anatomical pulmonary resection (lobectomy or bilobectomy). We analyzed the outcomes of patients receiving adjuvant chemotherapy. The risk factors for prognosis after surgery were also analyzed for NSCLC stage IB. RESULTS: Differences between the 5-year recurrence-free-survival (RFS) rates (71.4% vs. 60.2%, P=0.173) and the 5-year disease-specific-survival (DSS) rates (88.0% vs. 81.4%, P=0.437) obtained by patients receiving surgical treatment only versus patients receiving both surgery and adjuvant chemotherapy, retrospectively, were not significant. Multivariate analysis was conducted to identify the risk factors for recurrence and cancer-related death. Lymphovascular invasion was an independent risk factor for both recurrence and cancer-related death [hazard ratio (HR) =2.045, P=0.020; HR =3.150, P=0.048, respectively). CONCLUSIONS: Lymphovascular invasion was the only prognostic factor identified in patients with 8th edition stage IB NSCLC. Adjuvant chemotherapy was not an effective treatment for patients with stage IB NSCLC. The efficacy of adjuvant chemotherapy for stage IB patients with lymphovascular invasion should be evaluated in a future study.

Ro60 Inhibits Colonic Inflammation and Fibrosis in a Mouse Model of Dextran Sulfate Sodium-Induced Colitis.

Inflammatory bowel disease (IBD) is caused by chronic inflammation of the gastrointestinal tract. The pathogenesis of IBD remains unclear. The inflammation is associated with activation of T helper (Th) lymphocytes and chronic production of inflammatory cytokines. Ro60 suppresses the expression of tumor necrosis factor α, interleukin (IL)-6, and interferon α by inhibiting Alu transcription; control of Ro60 mRNA expression may thus be therapeutically useful. However, few studies have evaluated the anti-inflammatory activity of Ro60. The Ro60 level is decreased in IBD patients; we thus hypothesized that Ro60 was involved in the development of this autoimmune disease. We subjected mice with dextran sodium sulfate (DSS)-induced colitis to gene therapy using a vector that overexpressed Ro60 threefold. We scored IBD progression by repeatedly weighing the mice. Ro60 ameliorated colitis severity and reduced the levels of tumor necrosis factor α, IL-6, IL-17, IL-8, and vascular endothelial growth factor. Ro60 overexpression decreased the levels of α-smooth muscle actin (a marker of activated myofibroblasts) and type I collagen. The anti-inflammatory and anti-fibrotic activities of Ro60 ameliorated the severity of DSS-induced colitis in mice by repressing inflammation, fibrosis, angiogenesis, and the production of reactive oxygen species.

New bullae formation in the staple line increases the risk of recurrent pneumothorax following video-assisted thoracoscopic surgery bullectomy for primary spontaneous pneumothorax.

BACKGROUND: The study aimed to investigate the association between the recurrence of pneumothorax following video-assisted thoracoscopic surgery (VATS) for primary spontaneous pneumothorax (PSP) and the formation of new bullae. METHODS: This retrospective review examined patients who underwent VATS for PSP between April 2009 and December 2014. Of the 415 operated lungs, high-resolution computed tomography (HRCT) scans of 85 were analyzed. RESULTS: Of the 85 HRCT scans examined, 21 (24.7%) were diagnosed with recurrent pneumothorax and 60 new bullae were found. In total, 39 new bullae were located in the staple line, 38 were at other sites far from the staplers, and 17 were concurrent in the stapling and non-stapling areas. The group with new bullae in staple line exhibited significantly higher recurrence rate following VATS than the groups with no new bullae in the staple line (P=0.000, log-rank test). Cox regression analysis revealed that new bullae formation in the staple line [hazard ratio (HR), 26.664; P=0.003] and the volume of a resected pathology specimen (HR, 1.032; P=0.020) were independent risk factors for pneumothorax recurrence. CONCLUSIONS: New bullae formation in the staple line increases the risk of recurrent pneumothorax following VATS. Thus, the current concept of VATS bullectomy-resect with sufficient margin-warrants reconsideration.

Effect of invasive mucinous adenocarcinoma on lung cancer-specific survival after surgical resection: a population-based study.

BACKGROUND: In 2015, the World Health Organization (WHO) announced a new classification of lung tumors. Mucinous bronchioloalveolar adenocarcinomas were reclassified as invasive mucinous adenocarcinomas (IMAs). Due to the rarity or this tumor type, conflicting clinical outcomes have been reported based on small patient numbers. METHODS: Patients diagnosed as primary lung nonmucinous adenocarcinoma (NMA) or IMA from 2000 to 2014 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. General features of each IMA were explored and the effect of histological characteristics on lung cancer-specific survival was analyzed in matched samples using the TNM staging system. RESULTS: The incidence of IMA among all primary lung cancer patients was 0.2% (1,783/1,154,742), and the incidence of IMA among patients with a primary resected lung adenocarcinoma was 1.5% (531/35,406). IMAs tended to be located in the lower lobe (P<0.001), be well differentiated (P<0.001), and be N0 (91.7% vs. 72.3%, P<0.001), T1 or T2 (P<0.001), and stage I tumors (P<0.001) when compared with NMAs. After matching by stages, a stratified Cox PH analysis revealed that the tumor histologic type (P=0.2) did not increase the risk of lung cancer-specific death, while advanced age (HR 1.03, P<0.001), male sex, and the need for radiation, pneumonectomy or sublobar resections increased the risk of cancer-specific death. CONCLUSIONS: The histologic type of the tumor, whether IMA or not, did not affect lung cancer-specific survival times among patients with a primary M0 stage lung adenocarcinoma. When stratified by the TNM staging system, patents that required pneumonectomy, sublobar resection or radiation had shorter lung cancer-specific survival times.

Influence of lung resection volume on risk of primary spontaneous pneumothorax recurrence.

BACKGROUND: Thoracoscopic stapled bullectomy is a popular procedure for the treatment of primary spontaneous pneumothorax (PSP) that has a relatively high postoperative recurrence rate. One reason for PSP recurrence is the formation of a new bulla around the staple line. We hypothesized that different resected specimen volumes might cause differences in staple line tension. In this study, we analyzed the relationship between postoperative pneumothorax recurrence and resected lung volume. METHODS: Between April, 2009 and December 2013, 360 cases which underwent video-assisted thoracoscopic surgery (VATS) for PSP were selected. Recurrence after VATS was examined by electronic medical records and telephone survey. Resected volume and vertical area of specimen were calculated with the size of pathologic specimen. RESULTS: A mean follow up period was 44.5±24.4 months and recurrence rate was 11.1% (40/360). Large volume of resected specimen (≥16 cm3) (P=0.027 by the log-rank test) and larger vertical area of resected specimen (≥2.0 cm2) (P=0.003 by the log-rank test) showed significantly high recurrence rate. Cox regression analysis demonstrated that age [hazard ratio (HR), 0.083, P=0.006], vertical section area of resected specimen (HR, 1.239, P=0.020) and volume of resected pathology specimen (HR, 1.039, P=0.009) were independent risk factors of recurrence. CONCLUSIONS: Bulky resection during VATS for PSP increases the risk of recurrence. Large volume and vertical area of resected specimen are associated with greater tension in stapling line. Avoidance of wide resection and the firing of stapler after full collapse of lung are recommended for reducing the pneumothorax recurrence after VATS.