Does Surgical Removal of the Thymus Have Deleterious Consequences?

The role of immunosenescence, particularly the natural process of thymic involution during aging, is increasingly acknowledged as a factor contributing to the development of autoimmune diseases and cancer. Recently, a concern has been raised about deleterious consequences of the surgical removal of thymic tissue, including for patients who undergo thymectomy for myasthenia gravis (MG) or resection of a thymoma. This review adopts a multidisciplinary approach to scrutinize the evidence concerning the long-term risks of cancer and autoimmunity postthymectomy. We conclude that for patients with acetylcholine receptor antibody-positive MG and those diagnosed with thymoma, the removal of the thymus offers prominent benefits that well outweigh the potential risks. However, incidental removal of thymic tissue during other thoracic surgeries should be minimized whenever feasible.

The ASCENT Trial: a phase 2 study of induction and consolidation afatinib and chemoradiation with or without surgery in stage III EGFR-mutant NSCLC

BACKGROUND

The role of tyrosine kinase inhibitors (TKIs) in early-stage and metastatic oncogene-driven non-small cell lung cancer (NSCLC) is established, but it remains unknown how best to integrate TKIs with concurrent chemoradiotherapy (cCRT) in locally advanced disease. The phase 2 ASCENT trial assessed the efficacy and safety of afatinib and cCRT with or without surgery in locally advanced epidermal growth factor receptor (EGFR)-mutant NSCLC.

PATIENTS AND METHODS

Adults ≥18 years with histologically confirmed stage III (AJCC 7th edition) NSCLC with activating EGFR mutations were enrolled at Mass General and Dana-Farber/Brigham Cancer Centers, Boston, Massachusetts. Patients received induction afatinib 40 mg daily for 2 months, then cisplatin 75 mg/m2 and pemetrexed 500 mg/m2 IV every 3 weeks during RT (definitive or neoadjuvant dosing). Patients with resectable disease underwent surgery. All patients were offered consolidation afatinib for 2 years. The primary endpoint was the objective response rate (ORR) to induction TKI. Secondary endpoints were safety, conversion to operability, progression-free survival (PFS), and overall survival (OS). Analyses were performed on the intention-to-treat population.

RESULTS

Nineteen patients (median age 56 years; 74% female) were enrolled. ORR to induction afatinib was 63%. Seventeen patients received cCRT; 2/9 previously unresectable became resectable. Ten underwent surgery; 6 had a major or complete pathological response. Thirteen received consolidation afatinib. With a median follow-up of 5.0 years, median PFS and OS were 2.6 (95% CI, 1.4-3.1) and 5.8 years (2.9-NR), respectively. Sixteen recurred or died; 6 recurrences were isolated to CNS. The median time to progression after stopping consolidation TKI was 2.9 months (95% CI, 1.1-7.2). Four developed grade 2 pneumonitis. There were no treatment-related deaths.

CONCLUSION

We explored the efficacy of combining TKI with cCRT in oncogene-driven NSCLC. Induction TKI did not compromise subsequent receipt of multimodality therapy. PFS was promising, but the prevalence of CNS-only recurrences and rapid progression after TKI discontinuation speak to unmet needs in measuring and eradicating micrometastatic disease.

A Pilot Study Using Machine Learning Algorithms and Wearable Technology for the Early Detection of Postoperative Complications After Cardiothoracic Surgery

OBJECTIVE

To evaluate whether a machine learning algorithm (i.e. the "NightSignal" algorithm) can be used for the detection of postoperative complications prior to symptom onset after cardiothoracic surgery.

SUMMARY BACKGROUND DATA

Methods that enable the early detection of postoperative complications after cardiothoracic surgery are needed.

METHODS

This was a prospective observational cohort study conducted from July 2021 to February 2023 at a single academic tertiary care hospital. Patients aged 18 years or older scheduled to undergo cardiothoracic surgery were recruited. Study participants wore a Fitbit watch continuously for at least 1 week preoperatively and up to 90-days postoperatively. The ability of the NightSignal algorithm-which was previously developed for the early detection of Covid-19-to detect postoperative complications was evaluated. The primary outcomes were algorithm sensitivity and specificity for postoperative event detection.

RESULTS

A total of 56 patients undergoing cardiothoracic surgery met inclusion criteria, of which 24 (42.9%) underwent thoracic operations and 32 (57.1%) underwent cardiac operations. The median age was 62 (IQR: 51-68) years and 30 (53.6%) patients were female. The NightSignal algorithm detected 17 of the 21 postoperative events a median of 2 (IQR: 1-3) days prior to symptom onset, representing a sensitivity of 81%. The specificity, negative predictive value, and positive predictive value of the algorithm for the detection of postoperative events were 75%, 97%, and 28%, respectively.

CONCLUSIONS

Machine learning analysis of biometric data collected from wearable devices has the potential to detect postoperative complications-prior to symptom onset-after cardiothoracic surgery.

B cell-dependent subtypes and treatment-based immune correlates to survival in stage 3 and 4 lung adenocarcinomas

Lung cancer is the leading cause of cancer-related deaths worldwide. Surgery and chemoradiation are the standard of care in early stages of non-small cell lung cancer (NSCLC), while immunotherapy is the standard of care in late-stage NSCLC. The immune composition of the tumor microenvironment (TME) is recognized as an indicator for responsiveness to immunotherapy, although much remains unknown about its role in responsiveness to surgery or chemoradiation. In this pilot study, we characterized the NSCLC TME using mass cytometry (CyTOF) and bulk RNA sequencing (RNA-Seq) with deconvolution of RNA-Seq being performed by Kassandra, a recently published deconvolution tool. Stratification of patients based on the intratumoral abundance of B cells identified that the B-cell rich patient group had increased expression of CXCL13 and greater abundance of PD1+ CD8 T cells. The presence of B cells and PD1+ CD8 T cells correlated positively with the presence of intratumoral tertiary lymphoid structures (TLS). We then assessed the predictive and prognostic utility of these cell types and TLS within publicly available stage 3 and 4 lung adenocarcinoma (LUAD) RNA-Seq datasets. As previously described by others, pre-treatment expression of intratumoral 12-chemokine TLS gene signature is associated with progression free survival (PFS) in patients who receive treatment with immune checkpoint inhibitors (ICI). Notably and unexpectedly pre-treatment percentages of intratumoral B cells are associated with PFS in patients who receive surgery, chemotherapy, or radiation. Further studies to confirm these findings would allow for more effective patient selection for both ICI and non-ICI treatments.

Intralesional microbleeding in resected thymic cysts indeterminate on imaging

Background

The propensity of thymic cysts to mimic solid thymic epithelial tumors (TETs) on computed tomography (CT), on account of attenuation values greater than water and thickened or calcified walls, can lead to non-therapeutic thymectomy. These lesions can fluctuate in volume, CT attenuation, and magnetic resonance imaging (MRI) signal over time. We hypothesized that spontaneous hemorrhage and resorption may contribute to their variable appearance over time.

Methods

Completely excised thymic cysts were identified retrospectively over a 20-year period by their pathologic diagnosis. Cysts were excluded if they did not have available presurgical imaging, were not prevascular, were located within or contained an enhancing mass by imaging, or were of non-thymic origin upon microscopic review. Histopathological analysis of all available resected thymic cyst material and radiologic analysis of the cysts on pre-operative imaging were performed.

Results

Upon application of exclusion criteria, we identified 18 thymic cysts from the initial 85 mediastinal cystic specimens. Most cysts were unilocular (11/15, 73%), showed turbid-to-semisolid, hemorrhagic fluid (10/12, 83%) and showed histopathological findings suggestive of intralesional microbleeding (14/18, 78%), remodeling (8/18, 44%), pathological wound healing/scarring of the capsule (16/18, 89%), and fat necrosis in the surrounding thymic tissue (12/18, 67%). On CT, 6/17 (35%) cysts demonstrated wall calcification. Sixty-five percent (11/17) had attenuation values ≥20 Hounsfield units (HU). Two of the 4 cysts imaged by MRI were T1-isointense, one was mixed hyper- and isointense, and one T1-hypointense to muscle, with iso- and hyperintensity indicating hemorrhagic or proteinaceous content. Twenty-five percent (1/4) of cyst walls imaged by MRI were T1/T2-hypointense, indicating presence of calcification, hemosiderin, and/or fibrosis.

Conclusions

Resected thymic cysts in this cohort often showed features suggestive of intralesional microbleeding, inflammation, and fibrosis, which may explain their appearance and behavior over time on CT and MRI.

Management and outcomes of esophageal perforation

BACKGROUND

Esophageal perforation is a morbid condition and remains a therapeutic challenge. We report the outcomes of a large institutional experience with esophageal perforation and identify risk factors for morbidity and mortality.

METHODS

A retrospective analysis was conducted on 142 patients who presented with a thoracic or gastroesophageal junction esophageal perforation from 1995 to 2020. Baseline characteristics, operative or interventional strategies, and outcomes were analyzed by etiology of the perforation and management approach. Multivariable cox and logistic regression models were constructed to identify predictors of mortality and morbidity.

RESULTS

Overall, 109 (77%) patients underwent operative intervention, including 80 primary reinforced repairs and 21 esophagectomies and 33 (23%) underwent esophageal stenting. Stenting was more common in iatrogenic (27%) and malignant (64%) perforations. Patients who presented with a postemetic or iatrogenic perforation had similar 90-day mortality (16% and 16%) and composite morbidity (51% and 45%), whereas patients who presented with a malignant perforation had a 45% 90-day mortality and 45% composite morbidity. Risk factors for mortality included age >65 years (hazard ratio [HR] 1.89 [1.02-3.26], P = 0.044) and a malignant perforation (HR 4.80 [1.31-17.48], P = 0.017). Risk factors for composite morbidity included pleural contamination (odds ratio [OR] 2.06 [1.39-4.43], P = 0.046) and sepsis (OR 3.26 [1.44-7.36], P = 0.005). Of the 33 patients who underwent stent placement, 67% were successfully managed with stenting alone and 30% required stent repositioning.

CONCLUSIONS

Risk factors for morbidity and mortality after esophageal perforation include advanced age, pleural contamination, septic physiology, and malignant perforation. Primary reinforced repair remains a reasonable strategy for patients with an esophageal perforation from a benign etiology.

Diagnostic Accuracy of Endobronchial Optical Coherence Tomography for the Microscopic Diagnosis of Usual Interstitial Pneumonia

Rationale: Early, accurate diagnosis of interstitial lung disease (ILD) informs prognosis and therapy, especially in idiopathic pulmonary fibrosis (IPF). Current diagnostic methods are imperfect. High-resolution computed tomography has limited resolution, and surgical lung biopsy (SLB) carries risks of morbidity and mortality. Endobronchial optical coherence tomography (EB-OCT) is a low-risk, bronchoscope-compatible modality that images large lung volumes in vivo with microscopic resolution, including subpleural lung, and has the potential to improve the diagnostic accuracy of bronchoscopy for ILD diagnosis. Objectives: We performed a prospective diagnostic accuracy study of EB-OCT in patients with ILD with a low-confidence diagnosis undergoing SLB. The primary endpoints were EB-OCT sensitivity/specificity for diagnosis of the histopathologic pattern of usual interstitial pneumonia (UIP) and clinical IPF. The secondary endpoint was agreement between EB-OCT and SLB for diagnosis of the ILD fibrosis pattern. Methods: EB-OCT was performed immediately before SLB. The resulting EB-OCT images and histopathology were interpreted by blinded, independent pathologists. Clinical diagnosis was obtained from the treating pulmonologists after SLB, blinded to EB-OCT. Measurements and Main Results: We enrolled 31 patients, and 4 were excluded because of inconclusive histopathology or lack of EB-OCT data. Twenty-seven patients were included in the analysis (16 men, average age: 65.0 yr): 12 were diagnosed with UIP and 15 with non-UIP ILD. Average FVC and DlCO were 75.3% (SD, 18.5) and 53.5% (SD, 16.4), respectively. Sensitivity and specificity of EB-OCT was 100% (95% confidence interval, 75.8-100.0%) and 100% (79.6-100%), respectively, for both histopathologic UIP and clinical diagnosis of IPF. There was high agreement between EB-OCT and histopathology for diagnosis of ILD fibrosis pattern (weighted κ: 0.87 [0.72-1.0]). Conclusions: EB-OCT is a safe, accurate method for microscopic ILD diagnosis, as a complement to high-resolution computed tomography and an alternative to SLB.

Extended Pulmonary Resection by Sleeve Lobectomy and Carinal Pneumonectomy: Selection and Technique

Minimally invasive surgical approaches for extended pulmonary resections are becoming increasingly common as more surgeons gain experience in thoracoscopic and robotic technique. Outcome studies demonstrate improved decreased morbidity as compared with an open surgery.

Hyperbaric oxygen therapy in the prevention and management of tracheal and oesophageal anastomotic complications

OBJECTIVES

Failure of anastomotic healing is a morbid complication after airway or oesophageal surgery. Hyperbaric oxygen therapy (HBOT) has been used extensively in the management of complex wound-healing problems. We demonstrate the use of HBOT to rescue at-risk anastomoses or manage anastomotic failures in thoracic surgery.

METHODS

Retrospective review of 25 patients who received HBOT as part of the management of tracheal or oesophageal anastomotic problems during 2007-2018. HBOT was delivered at 2 atm with 100% oxygen in 90-min sessions.

RESULTS

Twenty-three patients underwent airway resection and reconstruction while 2 patients underwent oesophagectomy. There were 16 (70%) laryngotracheal and 7 (30%) tracheal resections. Necrosis at the airway anastomosis was found in 13 (57%) patients, partial dehiscence in 2 (9%) patients and both in 6 (26%) patients. HBOT was prophylactic in 2 (9%) patients. Patients received a median of 9.5 HBOT sessions (interquartile range 5-19 sessions) over a median course of 8 days. The airway anastomosis healed in 20 of 23 (87%) patients. Overall, a satisfactory long-term airway outcome was achieved in 19 (83%) patients; 4 patients failed and required reoperation (2 tracheostomies and 1 T-tube). HBOT was used in 2 patients after oesophagectomy to manage focal necrosis or ischaemia at the anastomosis, with success in 1 patient. Complications from HBOT were infrequent and mild (e.g. ear discomfort).

CONCLUSIONS

HBOT should be considered as an adjunct in the management of anastomotic problems after airway surgery. It may also play a role after oesophagectomy. Possible mechanisms of action are rapid granulation, early re-epithelialization and angiogenesis.

Pregnancy-associated idiopathic laryngotracheal stenosis: presentation, management and results of surgical treatment

OBJECTIVES

Idiopathic laryngotracheal stenosis (ILTS) is an uncommon problem arising mostly in women. In some, it arises during or is exacerbated by pregnancy. Experience with management of patients with this rare association is limited. This study seeks to evaluate the management of patients with pregnancy-associated ILTS and compare outcomes to cases not associated with pregnancy.

METHODS

Retrospective review of 15 patients undergoing surgical treatment of pregnancy-associated ILTS from 1971 to 2013. Variables of interest and airway outcomes were compared to patients with non-pregnancy-associated ILTS.

RESULTS

Pregnancy-associated ILTS was observed in 15/263 (5.7%) patients. Symptoms developed during their first pregnancy. When compared to non-pregnancy patients, these patients were younger (37 vs 47 years; P = 0.0003), had more prior tracheostomies (26.7% vs 10.9%; P = 0.085) and had more preoperative airway dilatations (86.7% vs 57.7%; P = 0.030). All patients completed pregnancy without complications and ultimately underwent laryngotracheal resection. The expression of hormonal receptors in the surgical specimens was similar in both groups (oestrogen receptors: 100% vs 75% and progesterone receptors: 71.4% vs 72.1%, in pregnancy and non-pregnancy patients, respectively). Airway outcomes were good/excellent in 13 (86.7%) patients with pregnancy-associated ILTS and 225 (90.7%) patients without pregnancy association (P = 0.642), and did not change when adjusting for other risk factors.

CONCLUSIONS

Pregnancy-associated ILTS is rare. The pathophysiology is unclear, but appearance of symptoms during pregnancy may suggest hormonal factors. To minimize foetal risk, dilatation during pregnancy followed by laryngotracheal resection after delivery is the preferred treatment. Pregnancy association does not seem to affect outcomes with expected satisfactory results in most patients.

Evaluation Of Release Maneuvers After Airway Reconstruction

BACKGROUND

Airway release (AR) maneuvers performed during airway resection to reduce anastomotic tension have not been thoroughly studied.

METHODS

We retrospectively analyzed consecutive resections for postintubation stenosis (PITS) and primary tracheal neoplasms (PTN) at a tertiary care center. Anastomotic complications were defined as stenosis, separation, necrosis, granulation tissue and air leak. Logistic regression modeling was used to identify factors associated with airway release and adverse outcome.

RESULTS

From 1993 to 2019, 545 patients with PITS (375; 68.8%) and PTN (170; 31.2%) underwent laryngotracheal (LTRR), tracheal (TRR) or carinal (CRR) resection; 5.7% (31/545) were reoperations. Release was performed in 11% (60/545): in 3.8% of LTRR (6/157; all laryngeal), 9.8% of TRR (34/347; laryngeal 12, hilar 22) and 49% of CRR (20/41; laryngeal 1, hilar 19). Mean resected length was 3.5 cm (range 1 - 6.3 cm) with release and 3.0 cm (0.8 - 6.5 cm) without (p<0.01). Operative mortality was 0.7% (4/545); all four anastomoses were intact until death. Anastomotic complications were present in 5% of AR patients (3/60) and in 9.3% (45/485) of no release (NoR) patients. AR was associated with resection length ≥ 4 cm (OR 6.15, 95% CI [1.37-27.65]), PTN (7.81 [3.31-18.40]), younger age (0.96 [0.94-0.98]) and lung resection (6.09 [1.33-27.90]). Anastomotic complications in patients with tracheal anastomoses were associated with pre-existing tracheostomy (2.68 [1.50-4.80]), but not release.

CONCLUSIONS

Tracheal reconstruction succeeds, even when anastomotic tension requires airway release. Since intraoperative assessment may underestimate tension, lowering the threshold for airway release seems prudent, particularly in patients with diabetes.

Initial and Longitudinal Cost of Surgical Resection for Lung Cancer

BACKGROUND

The longitudinal cost of treating patients with non-small cell lung cancer (NSCLC) undergoing surgical resection has not been evaluated. We describe initial and 4-year resource use and cost for NSCLC patients aged 65 years of age or greater who were treated surgically between 2008 and 2013.

METHODS

Using clinical data for NSCLC resections from The Society of Thoracic Surgeons General Thoracic Surgery Database linked to Medicare claims, resource use and cost of preoperative staging, surgery, and subsequent care through 4 years were examined ($2017). Cost of hospital-based care was estimated using cost-to-charge ratios; professional services and care in other settings were valued using reimbursements. Inverse probability weighting was used to account for administrative censoring. Outcomes were stratified by pathologic stage and by surgical approach for stage I lobectomy patients.

RESULTS

Resection hospitalizations averaged 6 days and cost $31,900. In the first 90 days, costs increased with stage ($12,430 for stage I to $26,350 for stage IV). Costs then declined toward quarterly means more similar among stages. Cumulative costs ranged from $131,032 (stage I) to $205,368 (stage IV). In the stage I lobectomy cohort, patients selected for minimally invasive procedures had lower 4-year costs than did thoracotomy patients ($120,346 versus $136,250).

CONCLUSIONS

The 4-year cost of surgical resection for NSCLC was substantial and increased with pathologic stage. Among stage I lobectomy patients, those selected for minimally invasive surgery had lower costs, particularly through 90 days. Potential avenues for improving the value of surgical resection include judicious use of postoperative intensive care and earlier detection and treatment of disease.

Non-small cell lung cancer: Analysis using mass cytometry and next generation sequencing reveals new opportunities for the development of personalized therapies

e21026

Background: Comprehensive molecular profiling and the use of biomarkers as companion diagnostics have transformed precision medicine for cancer patients. To identify patient-specific tumor microenvironment and biomarker profiles, we assessed the accuracy of our deconvolution algorithm in identifying cellular compositions from whole exome (WES) and whole transcriptome (RNA-seq) sequencing of solid tumors compared with cell populations identified by Mass Cytometry by Time of Flight (CyTOF) in surgically resected tissue from non-small cell lung cancer (NSCLC) patients. Methods: Resected NSCLC tissue was divided for RNA-seq and WES of whole tissue (n = 9) and for generating tissue single cell suspensions through mechanical dissociation and enzymatic digestion (n = 11). Bulk RNA-seq and CyTOF were performed on all cell suspensions. Cellular phenotypes were identified using clustering algorithms in CyTOF and predicted from bulk RNA-seq using our proprietary computational method. Results: Cellular composition reconstructed from RNA-seq correlated with the composition detected by CyTOF (R2= 0.922, n = 7) from cell suspensions. To recover the cell percentage from bulk RNA-seq, a machine learning framework was trained on the cell compendia comprising 7,117 unique cell type RNA-seq profiles. A two-stage hierarchical learning procedure generated a gradient boosting Light GBM model that included training on artificial RNA-seq mixtures of different cell types. With this method, we found that stromal and malignant cells were depleted during single cell suspension preparation, resulting in statistically significant differences in the tumor cell composition reconstructed from solid tissue and single cell suspensions. Immune cell types namely T cells and macrophages were similarly represented in both the bulk tumor tissue and matched single cell suspensions. Transcriptomics revealed a subgroup of patients whose tumors were B-cell-enriched, which was validated in other NSCLC cohorts and was associated with greater CD4+ and CD8+ T cell infiltration and improved clinical outcomes. Conclusions: Since preparation of single cell suspensions leads to the loss of several cellular components, RNA-seq of tumor bulk tissue better describes the molecular and cellular properties of the tumor microenvironment. The combination of RNA-seq and WES of tumor tissue provides a comprehensive profile of cellular composition, suggesting that this combination is ideal for precision medicine applications.

Equivalent Survival Between Lobectomy and Segmentectomy for Clinical Stage IA Lung Cancer

BACKGROUND

The oncologic efficacy of segmentectomy is controversial. We compared long-term survival in clinical stage IA (T1N0) Medicare patients undergoing lobectomy and segmentectomy in The Society of Thoracic Surgeons database.

METHODS

The Society of Thoracic Surgeons General Thoracic Surgery Database was linked to Medicare data in 14,286 lung cancer patients who underwent segmentectomy (n = 1654) or lobectomy (n = 12,632) for clinical stage IA disease from 2002 to 2015. Cox regression was used to create a long-term survival model. Patients were then propensity matched on demographic and clinical variables to derive matched pairs.

RESULTS

In Cox modeling segmentectomy was associated with survival similar to lobectomy in the entire cohort (hazard ratio, 1.04; 95% confidence interval, 0.89-1.20; P = .64) and in the matched subcohort. A subanalysis restricted to the 2009 to 2015 population (n = 11,811), when T1a tumors were specified and positron emission tomography results and mediastinal staging procedures were accurately recorded in the database, also showed that segmentectomy and lobectomy continue to have similar survival (hazard ratio, 1.00; 95% confidence interval, 0.87-1.16). Subanalysis of the pathologic N0 patients demonstrated the same results.

CONCLUSIONS

Lobectomy and segmentectomy for early-stage lung cancer are equally effective treatments with similar survival. Surgeons from The Society of Thoracic Surgeons database appear to be selecting patients appropriately for sublobar procedures.

Pulmonary Artery Resection During Lung Resection for Malignancy

BACKGROUND

Complete resection of central tumors invading the main pulmonary artery (PA) requires arterial reconstruction to avoid pneumonectomy. Oncologic equivalence with pneumonectomy has been suggested. We review clinical selection and outcome for these uncommon procedures in the context of candidacy for pneumonectomy.

METHODS

From 2000 to 2018, 9 different surgeons performed 34 pulmonary arterial resections for primary or metastatic pulmonary malignancy, with independent determination of pneumonectomy candidacy and arterioplasty technique. Patients undergoing limited lateral stapled PA resection (n = 3) or resection for metastasis (n = 3) were excluded from survival analysis.

RESULTS

The PA was resected as a sleeve with primary anastomosis (14.7%) or noncircumferentially with primary (61.8%), stapled (8.8%), or patch (14.7%) closure. Arterial resections represented between 2.5% and 43% of each surgeon's pneumonectomy volume. Sixteen (47%) patients were candidates for pneumonectomy. There was no operative mortality and 1 death at 47 days. Postoperative complications occurred in 21 (61.8%) patients. No patient required completion pneumonectomy. Overall 5-year survival was 33% (95% confidence interval [CI], 12-53). Compared with pulmonary arterioplasty alone, patients undergoing bronchial sleeve resection and pulmonary arterioplasty had better disease-free 5-year survival (50% [95% CI, 18-82] vs 19% [95% CI, 5-43]; P = .04), higher complete resection rate (100% [95% CI, 83-100] vs 80% [95% CI, 56-94]; P = .23) and lower disease recurrence (8% [n = 1 of 13] vs 47% [n = 7 of 15]; P = .04); 80% of disease recurrence was distant.

CONCLUSIONS

Resection and reconstruction of the PA for malignant lung disease may be safely performed. In candidates for pneumonectomy, arterial resection offers low operative risk. Long-term survival is impaired by distant, not local, recurrence emphasizing the importance of systemic therapy.

A new forest dwelling button spider from South Africa (Araneae, Theridiidae, Latrodectus)

The medically important spider genus Latrodectus Walckenaer 1805, commonly referred to as "button spiders" in South Africa, is represented by six species in the country. Using morphology and the COI barcoding gene we describe a new forest dwelling species, Latrodectus umbukwane n. sp. Wright, Wright, Lyle and Engelbrecht. Females have red markings on both the ventral and posterior dorsal surfaces of the abdomen, parallel spermathecae and three loops of the copulatory ducts. Males have an embolus with four loops and diagnostic white markings on the ventral surface of the abdomen that darken with age. Egg sacs are smooth, large, and bright purple when freshly laid, turning shiny grey with time. Latrodectus umbukwane n. sp. is known only from sand forest vegetation types in northern Zululand, KwaZulu-Natal, South Africa. A predicted geographic distribution for this species is provided based on cartographic mapping of known habitat and altitudinal preference, from which area of occupancy (AOO; 698 km2) and extent of occurrence (EOO; 4963 km2) were calculated to assess potential IUCN Red List status. Due to the uncertainty of the distribution of this species, a Red List status of Data Deficient (DD) is recommended. An updated key to the southern African species of Latrodectus is provided.

American Board of Thoracic Surgery 10-Year Maintenance of Certification Exam Improves and Validates Knowledge Acquisition

BACKGROUND

Previous "high-stakes" examinations by the American Board of Thoracic Surgery (ABTS) required remote testing, were noneducational, and were not tailored to individual practices. Given the ABTS mission of public safety and diplomate education, the ABTS Maintenance of Certification (MOC) examination was revised in 2015 to improve the educational experience and validate knowledge acquired.

METHODS

The ABTS-MOC Committee developed a web-based, secure examination tailored to the specialty-specific practice profile (cardiac, general thoracic, cardiothoracic, congenital) of the individual surgeon. After an initial answer to each question, an educational critique was reviewed before returning to the initial question and logging a second (final) response. Intraexam learning was assessed by comparing scores before and after reading the critique. Diplomate feedback was obtained.

RESULTS

A total of 988 diplomates completed the 10-year MOC examination between 2015 and 2017. Substantive learning was demonstrated with an 18%, 17%, 20%, and 9% improvement in cardiac, general thoracic, cardiothoracic, and congenital final scores, respectively. This improvement was most notable among diplomates with the lowest initial scores. Fewer diplomates failed the new exam (<1% vs 2.3%). Diplomate postexam survey highlighted marked improvements in clinical relevance (35% vs 78%), convenience (37% vs 78%), and learning (15% vs 45%). Over 80% acknowledged educational value, and 97% preferred the new format.

CONCLUSIONS

The new MOC process demonstrates increased knowledge acquisition through a convenient, secure, web-based practice-focused examination. This approach provides feedback, identifies baseline knowledge gaps for individual diplomates, and validates new knowledge attained.

Postintubation Tracheal Stenosis: Management and Results 1993 to 2017

BACKGROUND

To evaluate the management, complications of treatment, and outcomes of postintubation tracheal stenosis.

METHODS

A retrospective review was performed of records from a prospective database of all patients undergoing tracheal or laryngotracheal resection from 1993 to 2017 for postintubation tracheal stenosis. Redo operations after failure of initial resection and reconstruction for postintubation tracheal stenosis were included.

RESULTS

There were 392 patients whose ages ranged from 3 months to more than 84 years. A tracheostomy was performed in 275 as part of their care before surgery (present at time of resection in 123), dilations in 201, laser treatment in 82, T tubes in 66, and stents in 44 patients. Median length of resection was 3 cm. Laryngeal release was required in 15 of 392 (3.8%). Operative mortality was 0.8% (3 of 392); T tubes, tracheostomy present at resection, requirement for postoperative tracheostomy, and laryngeal involvement adversely impacted outcomes. Patients having tracheal resection and reconstruction had good or satisfactory outcomes in 96% (289 of 301) compared with 85% (77 of 91) having laryngotracheal resection. Complications within 30 days and at more than 30 days occurred in 116 patients and 14 patients, respectively. There were 96 anastomotic complications-68% minor (65 of 96), and 32% major (31 of 96). Necrosis of cartilage occurred in 12 patients and dehiscence in 14 patients.

CONCLUSIONS

Despite advances in care postintubation tracheal stenosis remains a challenging problem. Laryngotracheal resection and tracheostomy lead to worse outcomes. Excellent surgical results can be obtained for postintubation tracheal stenosis. Good results require careful evaluation, management of comorbid conditions, meticulous technique, minimizing tension, and preservation of blood supply.

Esophageal and Esophagogastric Junction Cancers, Version 2.2019, NCCN Clinical Practice Guidelines in Oncology

Esophageal cancer is the sixth leading cause of cancer-related deaths worldwide. Squamous cell carcinoma is the most common histology in Eastern Europe and Asia, and adenocarcinoma is most common in North America and Western Europe. Surgery is a major component of treatment of locally advanced resectable esophageal and esophagogastric junction (EGJ) cancer, and randomized trials have shown that the addition of preoperative chemoradiation or perioperative chemotherapy to surgery significantly improves survival. Targeted therapies including trastuzumab, ramucirumab, and pembrolizumab have produced encouraging results in the treatment of patients with advanced or metastatic disease. Multidisciplinary team management is essential for all patients with esophageal and EGJ cancers. This selection from the NCCN Guidelines for Esophageal and Esophagogastric Junction Cancers focuses on recommendations for the management of locally advanced and metastatic adenocarcinoma of the esophagus and EGJ.

Surgical Management of Acute and Chronic Pulmonary Embolism

Surgical pulmonary embolectomy and pulmonary thromboendarterectomy are well-established treatment strategies for patients with acute and chronic pulmonary embolism, respectively. For both procedures, techniques and outcomes have evolved considerably over the past decades. Patients with massive and submassive acute pulmonary embolism are at risk for rapid decline owing to right ventricular failure and shock. When thrombus is proximal, embolectomy can rapidly restore cardiac function. Chronic thromboembolic pulmonary hypertension is a more complex disease that requires skilled, careful dissection of the arterial wall, including vascular intima. When successful, surgery leads to clinical cure of the associated pulmonary hypertension, with excellent long-term outcomes.

All-optical spiking neurosynaptic networks with self-learning capabilities

Software implementations of brain-inspired computing underlie many important computational tasks, from image processing to speech recognition, artificial intelligence and deep learning applications. Yet, unlike real neural tissue, traditional computing architectures physically separate the core computing functions of memory and processing, making fast, efficient and low-energy computing difficult to achieve. To overcome such limitations, an attractive alternative is to design hardware that mimics neurons and synapses. Such hardware, when connected in networks or neuromorphic systems, processes information in a way more analogous to brains. Here we present an all-optical version of such a neurosynaptic system, capable of supervised and unsupervised learning. We exploit wavelength division multiplexing techniques to implement a scalable circuit architecture for photonic neural networks, successfully demonstrating pattern recognition directly in the optical domain. Such photonic neurosynaptic networks promise access to the high speed and high bandwidth inherent to optical systems, thus enabling the direct processing of optical telecommunication and visual data.

Feasibility of Perioperative Micro-Computed Tomography of Human Lung Cancer Specimens: A Pilot Study

CONTEXT.—

Lesion localization during intraoperative frozen section of lung resection specimens can be challenging. Imaging could aid lesion localization while enabling 3-dimensional specimen analysis.

OBJECTIVE.—

To assess the feasibility of integrating micro-computed tomography (micro-CT) into the perioperative evaluation of fresh surgical lung resection specimens.

DESIGN.—

Fresh lung specimens from patients with a presumptive diagnosis of lung cancer were imaged with micro-CT prior to routine histopathologic and molecular analysis. Micro-CT images were assessed to determine image quality, lesion size, and distance from lesion to the nearest surgical margin. Micro-CT measurements were compared to pathologic measurements using Bland-Altman analysis.

RESULTS.—

A total of 22 specimens from 21 patients were analyzed (mean image acquisition time, 13 ± 6 minutes). Histologic quality of imaged specimens was indistinguishable from a control group of nonimaged lung specimens. Artifacts, most commonly from specimen deflation (n = 8), obscured fine detail on micro-CT images of 10 specimens. Micro-CT could successfully localize the target lesion in the other 12 specimens. Distance to the nearest surgical margin was determined in 10 specimens. Agreement of micro-CT with final pathology was good, with a mean difference of -2.8% (limits of agreement -14.5% to 20.0%) for lesion size and -0.5 mm (limits of agreement -4.4 to 3.4 mm) for distance to nearest surgical margin.

CONCLUSIONS.—

Micro-CT of fresh surgical lung specimens is feasible and has the potential to evaluate the size and location of lesions within resection specimens, as well as distance to the nearest surgical margin, all without compromising specimen integrity.

Exploiting MCL1 Dependency with Combination MEK + MCL1 Inhibitors Leads to Induction of Apoptosis and Tumor Regression in KRAS-Mutant Non-Small Cell Lung Cancer

BH3 mimetic drugs, which inhibit prosurvival BCL2 family proteins, have limited single-agent activity in solid tumor models. The potential of BH3 mimetics for these cancers may depend on their ability to potentiate the apoptotic response to chemotherapy and targeted therapies. Using a novel class of potent and selective MCL1 inhibitors, we demonstrate that concurrent MEK + MCL1 inhibition induces apoptosis and tumor regression in KRAS-mutant non-small cell lung cancer (NSCLC) models, which respond poorly to MEK inhibition alone. Susceptibility to BH3 mimetics that target either MCL1 or BCL-xL was determined by the differential binding of proapoptotic BCL2 proteins to MCL1 or BCL-xL, respectively. The efficacy of dual MEK + MCL1 blockade was augmented by prior transient exposure to BCL-xL inhibitors, which promotes the binding of proapoptotic BCL2 proteins to MCL1. This suggests a novel strategy for integrating BH3 mimetics that target different BCL2 family proteins for KRAS-mutant NSCLC. SIGNIFICANCE: Defining the molecular basis for MCL1 versus BCL-xL dependency will be essential for effective prioritization of BH3 mimetic combination therapies in the clinic. We discover a novel strategy for integrating BCL-xL and MCL1 inhibitors to drive and subsequently exploit apoptotic dependencies of KRAS-mutant NSCLCs treated with MEK inhibitors.See related commentary by Leber et al., p. 1511.This article is highlighted in the In This Issue feature, p. 1494.

Surgical Management of Post-Esophagectomy Tracheo-Bronchial-Esophageal Fistula

BACKGROUND

Post-esophagectomy tracheo-bronchial-esophageal fistula (PETEF) most often develops after anastomotic disruption or gastric conduit necrosis. Ideal surgical management and outcomes for this complication are uncertain.

METHODS

A retrospective review of 11 patients undergoing surgical repair of PETEF was performed.

RESULTS

The median time between esophagectomy and surgical repair of PETEF was 61 days (range, 7 days to 28 years). Anastomotic leak or gastric conduit necrosis was responsible for PETEF in 6 patients (54.5%), whereas other causes were erosion of a tracheal appliance (n = 2), gastric conduit staple line erosion (n = 1), anastomotic stricture dilation (n = 1), and recurrent esophageal cancer (n = 1). Membranous airway defects were repaired primarily and buttressed with muscle or omental flaps in 8 patients (72.7%), whereas two (18.2%) were repaired with bio-prosthetic patches and one (9.1%) was repaired with a sleeve resection of the bronchus. Anastomotic and neo-esophageal conduit defects were repaired primarily in 3 patients (27.3%), whereas 7 patients (63.6%) underwent conduit take-down and esophageal or pharyngeal diversion, and 1 patient (9.1%) underwent simultaneous fistula repair and colon interposition. Two patients (18.2%) had recurrent fistulas, with 1 patient dying after second fistula closure and the other was discharged with no further attempt at repair. Three patients (27.3%) died postoperatively. Only 3 patients (27.3%) resumed an oral diet after fistula repair.

CONCLUSIONS

Surgical treatment is effective for most patients undergoing operative repair of PETEF, notwithstanding a considerable risk of postoperative morbidity and death. Although fistula repair is life saving and prevents further respiratory deterioration, return to oral alimentation is not ensured.

Minimally Invasive Lung Cancer Surgery Performed by Thoracic Surgeons as Effective as Thoracotomy

Purpose The prevalence of minimally invasive lung cancer surgery using video-assisted thoracic surgery (VATS) has increased dramatically over the past decade, yet recent studies have suggested that the lymph node evaluation during VATS lobectomy is inadequate. We hypothesized that the minimally invasive approach to lobectomy for stage I lung cancer resulted in a longitudinal outcome that was not inferior to thoracotomy. Patients and Methods Patients > 65 years of age who had undergone lobectomy for stage I lung cancer between 2002 and 2013 were analyzed within the Society of Thoracic Surgeons General Thoracic Surgery Database, which had been linked to Medicare data, as part of a retrospective-cohort, noninferiority study. Results A total of 10,597 patients with clinical stage I lung cancer who underwent lobectomy were evaluated (4,448 patients underwent thoracotomy, and 6,149 underwent VATS). VATS patients had a more favorable distribution of all health-related variables, including pulmonary function (59% of VATS patients had intact spirometry v 51% of thoracotomy patients; P < .001). Cox proportional hazards models were performed over two eras to account for an evolving practice standard. The mortality risk associated with the VATS approach was not greater than thoracotomy in either the earlier era (2002 to 2008; hazard ratio, 0.97; 95% CI, 0.87 to 1.09; P = .62) or the more recent era (2009 to 2013; hazard ratio, 0.84; 95% CI, 0.75 to 0.93; P < .001). Kaplan-Meier survival estimates of 2,901 propensity-matched VATS-thoracotomy pairs demonstrated that the 4-year survival associated with VATS (68.6%) was modestly superior to thoracotomy (64.8%; P = .003). The analyses detailed above were replicated in a separate cohort of pathologic stage I patients with similar findings. Conclusion The long-term efficacy of lobectomy for stage I lung cancer performed using the VATS approach by board-certified thoracic surgeons does not seem to be inferior to that of thoracotomy.

A self-resetting spiking phase-change neuron

Neuromorphic, or brain-inspired, computing applications of phase-change devices have to date concentrated primarily on the implementation of phase-change synapses. However, the so-called accumulation mode of operation inherent in phase-change materials and devices can also be used to mimic the integrative properties of a biological neuron. Here we demonstrate, using physical modelling of nanoscale devices and SPICE modelling of associated circuits, that a single phase-change memory cell integrated into a comparator type circuit can deliver a basic hardware mimic of an integrate-and-fire spiking neuron with self-resetting capabilities. Such phase-change neurons, in combination with phase-change synapses, can potentially open a new route for the realisation of all-phase-change neuromorphic computing.

New routes to the functionalization patterning and manufacture of graphene-based materials for biomedical applications

Graphene-based materials are being widely explored for a range of biomedical applications, from targeted drug delivery to biosensing, bioimaging and use for antibacterial treatments, to name but a few. In many such applications, it is not graphene itself that is used as the active agent, but one of its chemically functionalized forms. The type of chemical species used for functionalization will play a key role in determining the utility of any graphene-based device in any particular biomedical application, because this determines to a large part its physical, chemical, electrical and optical interactions. However, other factors will also be important in determining the eventual uptake of graphene-based biomedical technologies, in particular the ease and cost of manufacture of proposed device and system designs. In this work, we describe three novel routes for the chemical functionalization of graphene using oxygen, iron chloride and fluorine. We also introduce novel in situ methods for controlling and patterning such functionalization on the micro- and nanoscales. Our approaches are readily transferable to large-scale manufacturing, potentially paving the way for the eventual cost-effective production of functionalized graphene-based materials, devices and systems for a range of important biomedical applications.

Nonoperative Endoscopic Management of Benign Tracheobronchial Disorders

Modern thoracic surgery requires knowledge and skill in advanced bronchoscopic techniques. Rigid bronchoscopy remains a workhorse for the management of central airway obstruction. Dilation of tracheal strictures is now much simpler with the advent of the balloon dilator, which can be passed through a therapeutic bronchoscope. Numerous adjuncts, such as laser, argon beam coagulation, electrocautery, and cryotherapy, can be used to improve airway patency. There are now numerous stenting options for strictures that require stenting to maintain airway patency.

The Society of Thoracic Surgeons General Thoracic Surgery Database 2018 Update on Outcomes and Quality

For nearly 15 years The Society of Thoracic Surgeons General Thoracic Surgery Database (STS GTSD) has provided participating institutions with risk-adjusted feedback reports that allow outcome comparisons relative to national benchmarks. With more than 300 contributing centers across North America, the STS GTSD now includes more than 530,000 cases. In 2017 the STS GTSD Task Force revised the data collection form with the goal of collecting more detailed and accurate information for the most important thoracic surgical cases without increasing the workload of registrars. In addition, the learning curve for thoracoscopic lobectomy was examined, online public reporting was initiated, institutional feedback reports were made more user-friendly, and collaboration with the European Society of Thoracic Surgery continued. The STS GTSD Task Force continues to work to improve the quality of care and support research initiatives in general thoracic surgery. This report summarizes current aggregate national outcomes in general thoracic surgery and reviews related activities in the areas of quality measurement, performance improvement, and transparency from the STS GTSD during the past 12 months.

Tracheobronchoplasty for tracheomalacia

Tracheobronchomalacia is an uncommon acquired disorder of the central airways. Common symptoms include dyspnea, constant coughing, inability to raise secretions and recurrent respiratory infections. Evaluation includes an inspiratory-expiratory chest computed tomography (dynamic CT), an awake functional bronchoscopy and pulmonary function studies. Patients with significant associated symptoms and severe collapse on CT and bronchoscopy are offered membraneous wall plication. Tracheobronchoplasty is performed through a right thoracotomy. The posterior airway is exposed after the azygous vein is ligated. The posterior wall of the trachea (and usually both main bronchi) is plicated to a sheet of thick acellular dermis (or polypropylene mesh) with a series of 4 mattress sutures of 4-0 sutures from the thoracic inlet to the bottom of the trachea to re-shape the trachea and restore the normal D shape. Patients report generally good results with improvement of their symptoms. Quality of life is usually improved while pulmonary function tests usually are not improved.

Memristive effects in oxygenated amorphous carbon nanodevices

Computing with resistive-switching (memristive) memory devices has shown much recent progress and offers an attractive route to circumvent the von-Neumann bottleneck, i.e. the separation of processing and memory, which limits the performance of conventional computer architectures. Due to their good scalability and nanosecond switching speeds, carbon-based resistive-switching memory devices could play an important role in this respect. However, devices based on elemental carbon, such as tetrahedral amorphous carbon or ta-C, typically suffer from a low cycling endurance. A material that has proven to be capable of combining the advantages of elemental carbon-based memories with simple fabrication methods and good endurance performance for binary memory applications is oxygenated amorphous carbon, or a-CO _x . Here, we examine the memristive capabilities of nanoscale a-CO _x devices, in particular their ability to provide the multilevel and accumulation properties that underpin computing type applications. We show the successful operation of nanoscale a-CO _x memory cells for both the storage of multilevel states (here 3-level) and for the provision of an arithmetic accumulator. We implement a base-16, or hexadecimal, accumulator and show how such a device can carry out hexadecimal arithmetic and simultaneously store the computed result in the self-same a-CO _x cell, all using fast (sub-10 ns) and low-energy (sub-pJ) input pulses.

Quantifying the learning curve for pulmonary thromboendarterectomy

BACKGROUND

Pulmonary thromboendarterectomy (PTE) is an effective treatment for chronic thromboembolic pulmonary hypertension (CTEPH), but is a technically challenging operation for cardiothoracic surgeons. Starting a new program allows an opportunity to define a learning curve for PTE.

METHODS

A retrospective case review was performed of 134 consecutive PTEs performed from 1998 to 2016 at a single institution. Outcomes were compared using either a two-tailed t-test for continuous variables or a chi-squared test for categorical variables according to experience of the program by terciles (T).

RESULTS

The 30-day mortality was 3.7%. The mean length of hospital stay, length of ICU stay, and duration on a ventilator were 12.6 days, 4.6 days, and 2.0 days, respectively. The mean decrease in systolic pulmonary artery pressure (sPAP) was 41.3 mmHg. Patients with Jamieson type 2 disease had a greater change in mean sPAP than those with type 3 disease (p = 0.039). The mean cardiopulmonary bypass time was 180 min (T1-198 min, T3-159 min, p = <0.001), and the mean circulatory arrest time was 37 min (T1-44 min, T3-31 min, p < 0.001). Plotting circulatory arrest times as a running sum compared to the mean demonstrated 2 inflection points, the first at 22 cases and the second at 95 cases.

CONCLUSIONS

PTE is a challenging procedure to learn, and good outcomes are a result of a multi-disciplinary effort to optimize case selection, operative performance, and postoperative care. Approximately 20 cases are needed to become proficient in PTE, and nearly 100 cases are required for more efficient clearing of obstructed pulmonary arteries.