Automated Real-Time Detection of Lung Sliding Using Artificial Intelligence: A Prospective Diagnostic Accuracy Study.

BACKGROUND: Rapid evaluation for pneumothorax is a common clinical priority. Although lung ultrasound (LUS) often is used to assess for pneumothorax, its diagnostic accuracy varies based on patient and provider factors. To enhance the performance of LUS for pulmonary pathologic features, artificial intelligence (AI)-assisted imaging has been adopted; however, the diagnostic accuracy of AI-assisted LUS (AI-LUS) deployed in real time to diagnose pneumothorax remains unknown. RESEARCH QUESTION: In patients with suspected pneumothorax, what is the real-time diagnostic accuracy of AI-LUS to recognize the absence of lung sliding? STUDY DESIGN AND METHODS: We performed a prospective AI-assisted diagnostic accuracy study of AI-LUS to recognize the absence of lung sliding in a convenience sample of patients with suspected pneumothorax. After calibrating the model parameters and imaging settings for bedside deployment, we prospectively evaluated its diagnostic accuracy for lung sliding compared with a reference standard of expert consensus. RESULTS: Two hundred forty-one lung sliding evaluations were derived from 62 patients. AI-LUS showed a sensitivity of 0.921 (95% CI, 0.792-0.973), specificity of 0.802 (95% CI, 0.735-0.856), area under the receiver operating characteristic curve of 0.885 (95% CI, 0.828-0.956), and accuracy of 0.824 (95% CI, 0.766-0.870) for the diagnosis of absent lung sliding. INTERPRETATION: In this study, real-time AI-LUS showed high sensitivity and moderate specificity to identify the absence of lung sliding. Further research to improve model performance and optimize the integration of AI-LUS into existing diagnostic pathways is warranted.

What is the predictive value of RECIST criteria following stereotactic lung radiation?

PURPOSE: Response EvaluationCriteriain Solid Tumors (RECIST) is commonly used to assess response to anti-cancer therapies. However, its application after lung stereotactic ablative radiotherapy (SABR) is complicated by radiation-induced lung changes. This study assesses the frequency of progressive disease (PD) by RECIST following lung SABR and correlates this with actual treatment outcomes as determined by longitudinal follow-up. METHODS AND MATERIALS: We reviewed patients treated with lung SABR for primary lung tumors or oligometastases between 2010 and 2015. Patients were treated with SABR doses of 54-60 Gy in 3-8 fractions. All follow-up scans were assessed and the treated lesion was serially measured over time, with the maximum diameter on axial CT slices used for RECIST calculations. Lesions demonstrating PD by RECIST criteria were identified and subsequently followed for long-term outcomes. The final 'gold-standard' assessment of response was based on size changes after PD and, as available, positron emission tomography scan and/or biopsy. RESULTS: Eighty-eight lesions met inclusion criteria. Seventy-five were lung primaries and thirteen were lung metastases. Median follow-up was 52 months (interquartile range: 33-68). Two-thirds (66 %, 58/88) of treated lesions met RECIST criteria for PD; however, local recurrence was only confirmed in 16 % (9/58) of cases. Most lesions that triggered PD by RECIST (47/58, 81 %) were ultimately found not to represent recurrence, while a minority (2/58, 3 %) had an uncertain response. The positive predictive value [PPV] of a RECIST defined PD event was 0.16. If PD was triggered within 12-months post-treatment, PPV was 0.08, compared to 0.21 for lesions triggering PD after 12-months. CONCLUSION: Using RECIST criteria, two-thirds of patients treated with lung SABR met criteria for PD. However, only a minority had recurrence, leading to a poor PPV of RECIST. This highlights the limitations of RECIST in this setting and provides context for physicians when interpreting post-lung SABR imaging.

Multicentre positive deviance seminar to generate best practice recommendations to reduce anastomotic leak and length of stay for patients undergoing oesophagectomy.

BACKGROUND: We describe a novel process using positive deviance (PD) with the Canadian Association of Thoracic Surgeons members, to identify perioperative best practice to minimise anastomotic leak (AL) and length of stay (LOS) following oesophagectomy. To our knowledge, this is the first National combination of level 1 evidence with expert opinion (ie, PD seminar) aimed at reducing AL and LOS in oesophageal surgery. Our primary hypothesis is that a multicentre National PD seminar is feasible, and could lead to the generation of best practices recommendations aimed at reducing AL and LOS in patients with oesophageal cancer. METHODS: Adverse events, LOS and AL incidence/severity following oesophagectomy were prospectively collected from seven Canadian thoracic institutions using Thoracic Morbidity and Mortality classification system (2017-2020). Anonymised display of centre's data were presented, with identification of centres demonstrating PD. Surgeons from PD sites discussed principles of care, culminating in the consensus recommendations, anonymously rated by all (5-point Likert scale). RESULTS: Data from 795 esophagectomies were included, with 25 surgeons participating. Two centres were identified as having the lowest AL rates 44/395 (11.1%) (vs five centres 71/400 (17.8%) (p<0.01)) and shortest LOS 8 days 45 (IQR: 6-14) (vs 10 days (IQR: 8-18) (p<0.001)). Recommendations included preoperative (prehabilitation, smoking cessation, chemotherapy for patients with dysphagia, minimise stents/feeding tubes), intraoperative (narrow gastric conduit, intrathoracic anastomosis, avoid routine jejunostomy, use small diameter closed-suction drains), postoperative day (POD) (early (POD 2-3) enteral feeding initiation, avoid routine barium swallow studies, early removal of tubes/drains (POD 2-3)). All ranked above 80% (4/5) in agreement to implement recommendations into their practice. CONCLUSION: We report the feasibility of a National multicentre PD seminar with the generation of best practice recommendations aimed at reducing AL and LOS following oesophagectomy. Further research is required to demonstrate whether National PD seminars can be an effective quality improvement tool.

Stereotactic ablative radiotherapy before resection to avoid delay for early-stage lung cancer or oligometastases during the COVID-19 pandemic: Pathologic outcomes from the SABR-BRIDGE protocol.

BACKGROUND: During coronavirus disease 2019 (COVID-19)-related operating room closures, some multidisciplinary thoracic oncology teams adopted a paradigm of stereotactic ablative radiotherapy (SABR) as a bridge to surgery, an approach called SABR-BRIDGE. This study presents the preliminary surgical and pathological results. METHODS: Eligible participants from four institutions (three in Canada and one in the United States) had early-stage presumed or biopsy-proven lung malignancy that would normally be surgically resected. SABR was delivered using standard institutional guidelines, with surgery >3 months following SABR with standardized pathologic assessment. Pathological complete response (pCR) was defined as absence of viable cancer. Major pathologic response (MPR) was defined as ≤10% viable tissue. RESULTS: Seventy-two patients underwent SABR. Most common SABR regimens were 34 Gy/1 (29%, n = 21), 48 Gy/3-4 (26%, n = 19), and 50/55 Gy/5 (22%, n = 16). SABR was well-tolerated, with one grade 5 toxicity (death 10 days after SABR with COVID-19) and five grade 2-3 toxicities. Following SABR, 26 patients underwent resection thus far (13 pending surgery). Median time-to-surgery was 4.5 months post-SABR (range, 2-17.5 months). Surgery was reported as being more difficult because of SABR in 38% (n = 10) of cases. Thirteen patients (50%) had pCR and 19 (73%) had MPR. Rates of pCR trended higher in patients operated on at earlier time points (75% if within 3 months, 50% if 3-6 months, and 33% if ≥6 months; p = .069). In the exploratory best-case scenario analysis, pCR rate does not exceed 82%. CONCLUSIONS: The SABR-BRIDGE approach allowed for delivery of treatment during a period of operating room closure and was well-tolerated. Even in the best-case scenario, pCR rate does not exceed 82%.

Multicentre positive deviance to reduce adverse events and length of stay after pulmonary resection.

BACKGROUND: Postoperative adverse events (AEs) following pulmonary resection enormously impact patient well-being, length of stay (LOS) and healthcare costs. Standardised AE data collection can be used to identify positive outliers demonstrating positive deviance (PD) who may be helpful to inform the best practice. Here, we describe our initial experience of a novel quality improvement process using PD to reduce LOS and AEs. METHODS: AE rates and LOS were collected from four centres (2014-2020) using a common dictionary. Surgeons repeatedly participated in 60 to 90 min seminars consisting of the following process: identify outcome and procedure targeted, review relevant best evidence literature, view all data anonymised by surgeon or centre (if multicentre), choose and reveal identity of best performance PD outliers, who discuss their management principles while all receive self-evaluation reports, followed by collegial discussion to generate consensus recommendations, voted by all. We assessed overall impact on AEs and LOS using aggregate data in a before/after analysis. RESULTS: A total of 131 surgeons (average 12/seminar) participated in 11 PD seminars (8 local and 3 multicentre), yielding 85 consensus recommendation (average 8/seminar). Median LOS following lobectomy decreased from 4.0 to 3.0 days (p=0.04) following local PD seminars and from 4.0 to 3.5 days (p=0.11) following multicentre seminars. Trends for reductions in multiple AE rates were also observed. CONCLUSION: While limited by the longitudinal design, these findings provide preliminary support for this data-driven, collegial and actionable quality improvement process to help standardise and improve patient care, and merits further more rigorous investigation.

Predicting recurrence risks in lung cancer patients using multimodal radiomics and random survival forests.

Purpose: We developed a model integrating multimodal quantitative imaging features from tumor and nontumor regions, qualitative features, and clinical data to improve the risk stratification of patients with resectable non-small cell lung cancer (NSCLC). Approach: We retrospectively analyzed 135 patients [mean age, 69 years (43 to 87, range); 100 male patients and 35 female patients] with NSCLC who underwent upfront surgical resection between 2008 and 2012. The tumor and peritumoral regions on both preoperative CT and FDG PET-CT and the vertebral bodies L3 to L5 on FDG PET were segmented to assess the tumor and bone marrow uptake, respectively. Radiomic features were extracted and combined with clinical and CT qualitative features. A random survival forest model was developed using the top-performing features to predict the time to recurrence/progression in the training cohort ( n = 101 ), validated in the testing cohort ( n = 34 ) using the concordance, and compared with a stage-only model. Patients were stratified into high- and low-risks of recurrence/progression using Kaplan-Meier analysis. Results: The model, consisting of stage, three wavelet texture features, and three wavelet first-order features, achieved a concordance of 0.78 and 0.76 in the training and testing cohorts, respectively, significantly outperforming the baseline stage-only model results of 0.67 ( p < 0.005 ) and 0.60 ( p = 0.008 ), respectively. Patients at high- and low-risks of recurrence/progression were significantly stratified in both the training ( p < 0.005 ) and the testing ( p = 0.03 ) cohorts. Conclusions: Our radiomic model, consisting of stage and tumor, peritumoral, and bone marrow features from CT and FDG PET-CT significantly stratified patients into low- and high-risk of recurrence/progression.

Circulating tumor cells detected in follow-up predict survival outcomes in tri-modality management of advanced non-metastatic esophageal cancer: a secondary analysis of the QUINTETT randomized trial.

BACKGROUND: Our aim was to establish if presence of circulating tumor cells (CTCs) predicted worse outcome in patients with non-metastatic esophageal cancer undergoing tri-modality therapy. METHODS: We prospectively collected CTC data from patients with operable non-metastatic esophageal cancer from April 2009 to November 2016 enrolled in our QUINTETT esophageal cancer randomized trial (NCT00907543). Patients were randomized to receive either neoadjuvant cisplatin and 5-fluorouracil (5-FU) plus radiotherapy followed by surgical resection (Neoadjuvant) or adjuvant cisplatin, 5-FU, and epirubicin chemotherapy with concurrent extended volume radiotherapy following surgical resection (Adjuvant). CTCs were identified with the CellSearch® system before the initiation of any treatment (surgery or chemoradiotherapy) as well as at 6-, 12-, and 24-months post-treatment. The threshold for CTC positivity was one and the findings were correlated with patient prognosis. RESULTS: CTC data were available for 74 of 96 patients and identified in 27 patients (36.5%) at a median follow-up of 13.1months (interquartile range:6.8-24.1 months). Detection of CTCs at any follow-up visit was significantly predictive of worse disease-free survival (DFS;hazard ratio [HR]: 2.44; 95% confidence interval [CI]: 1.41-4.24; p=0.002), regional control (HR: 6.18; 95% CI: 1.18-32.35; p=0.031), distant control (HR: 2.93; 95% CI: 1.52-5.65;p=0.001) and overall survival (OS;HR: 2.02; 95% CI: 1.16-3.51; p=0.013). After adjusting for receiving neoadjuvant vs. adjuvant chemoradiotherapy, the presence of CTCs at any follow-up visit remained significantly predictive of worse OS ([HR]:2.02;95% [Cl]:1.16-3.51; p=0.013) and DFS (HR: 2.49;95% Cl: 1.43-4.33; p=0.001). Similarly, any observed increase in CTCs was significantly predictive of worse OS (HR: 3.14; 95% CI: 1.56-6.34; p=0.001) and DFS (HR: 3.34; 95% CI: 1.67-6.69; p<0.001). CONCLUSION: The presence of CTCs in patients during follow-up after tri-modality therapy was associated with significantly poorer DFS and OS regardless of timing of chemoradiotherapy.

The quality of life in neoadjuvant versus adjuvant therapy of esophageal cancer treatment trial (QUINTETT): Randomized parallel clinical superiority trial.

BACKGROUND: We compared the health-related quality of life (HRQOL) in patients undergoing trimodality therapy for resectable stage I-III esophageal cancer. METHODS: A total of 96 patients were randomized to standard neoadjuvant cisplatin and 5-fluorouracil chemotherapy plus radiotherapy (neoadjuvant) followed by surgical resection or adjuvant cisplatin, 5-fluorouracil, and epirubicin chemotherapy with concurrent extended volume radiotherapy (adjuvant) following surgical resection. RESULTS: There was no significant difference in the functional assessment of cancer therapy-esophageal (FACT-E) total scores between arms at 1 year (p = 0.759) with 36% versus 41% (neoadjuvant vs. adjuvant), respectively, showing an increase of ≥15 points compared to pre-treatment (p = 0.638). The HRQOL was significantly inferior at 2 months in the neoadjuvant arm for FACT-E, European Organization for Research and Treatment of Cancer quality of life questionnaire (EORTC QLQ-OG25), and EuroQol 5-D-3 L in the dysphagia, reflux, pain, taste, and coughing domains (p < 0.05). Half of patients were able to complete the prescribed neoadjuvant arm chemotherapy without modification compared to only 14% in the adjuvant arm (p < 0.001). Chemotherapy related adverse events of grade ≥2 occurred significantly more frequently in the neoadjuvant arm (100% vs. 69%, p < 0.001). Surgery related adverse events of grade ≥2 were similar in both arms (72% vs. 86%, p = 0.107). There were no 30-day mortalities and 2% vs. 10% 90-day mortalities (p = 0.204). There were no significant differences in either overall survival (OS) (5-year: 35% vs. 32%, p = 0.409) or disease-free survival (DFS) (5-year: 31% vs. 30%, p = 0.710). CONCLUSION: Trimodality therapy is challenging for patients with resectable esophageal cancer regardless of whether it is given before or after surgery. Newer and less toxic protocols are needed.

Surgery crisis simulation during the COVID-19 pandemic.

SummaryCOVID-19 puts health care providers at risk for infection with SARS-CoV-2. Personal protective equipment (PPE) can reduce viral transmission if used properly. We used simulation of an intraoperative crisis involving an infectious outbreak to assess PPE adherence and confidence in PPE use. Simulation of an intraoperative crisis with a patient with COVID-19 revealed gaps in PPE adherence; however, simulation training successfully increased confidence in PPE use and received positive feedback.

Predicting pathological complete response (pCR) after stereotactic ablative radiation therapy (SABR) of lung cancer using quantitative dynamic [18F]FDG PET and CT perfusion: a prospective exploratory clinical study.

BACKGROUND: Stereotactic ablative radiation therapy (SABR) is effective in treating inoperable stage I non-small cell lung cancer (NSCLC), but imaging assessment of response after SABR is difficult. This prospective study aimed to develop a predictive model for true pathologic complete response (pCR) to SABR using imaging-based biomarkers from dynamic [18F]FDG-PET and CT Perfusion (CTP). METHODS: Twenty-six patients with early-stage NSCLC treated with SABR followed by surgical resection were included, as a pre-specified secondary analysis of a larger study. Dynamic [18F]FDG-PET and CTP were performed pre-SABR and 8-week post. Dynamic [18F]FDG-PET provided maximum and mean standardized uptake value (SUV) and kinetic parameters estimated using a previously developed flow-modified two-tissue compartment model while CTP measured blood flow, blood volume and vessel permeability surface product. Recursive partitioning analysis (RPA) was used to establish a predictive model with the measured PET and CTP imaging biomarkers for predicting pCR. The model was compared to current RECIST (Response Evaluation Criteria in Solid Tumours version 1.1) and PERCIST (PET Response Criteria in Solid Tumours version 1.0) criteria. RESULTS: RPA identified three response groups based on tumour blood volume before SABR (BVpre-SABR) and change in SUVmax (ΔSUVmax), the thresholds being BVpre-SABR = 9.3 mL/100 g and ΔSUVmax = - 48.9%. The highest true pCR rate of 92% was observed in the group with BVpre-SABR < 9.3 mL/100 g and ΔSUVmax < - 48.9% after SABR while the worst was observed in the group with BVpre-SABR ≥ 9.3 mL/100 g (0%). RPA model achieved excellent pCR prediction (Concordance: 0.92; P = 0.03). RECIST and PERCIST showed poor pCR prediction (Concordance: 0.54 and 0.58, respectively). CONCLUSIONS: In this study, we developed a predictive model based on dynamic [18F]FDG-PET and CT Perfusion imaging that was significantly better than RECIST and PERCIST criteria to predict pCR of NSCLC to SABR. The model used BVpre-SABR and ΔSUVmax which correlates to tumour microvessel density and cell proliferation, respectively and warrants validation with larger sample size studies. TRIAL REGISTRATION: MISSILE-NSCLC, NCT02136355 (ClinicalTrials.gov). Registered May 8, 2014, https://clinicaltrials.gov/ct2/show/NCT02136355.

Idiopathic Subglottic Stenosis: An Institutional Review of Outcomes With a Multimodality Surgical Approach.

OBJECTIVES: This article reports on a unique cohort of patients with idiopathic subglottic stenosis spilt fairly equally between endoscopic and open surgical approaches. Patients' sequence of operations and reinterventions over time are outlined, offering insight to improve surgical counseling and allow for informative, autonomous patient decision making. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary care academic center. METHODS: Cases of consecutive adults with idiopathic subglottic stenosis managed surgically over a 12-year period (January 2006-December 2017) were retrospectively reviewed. Surgical workflow, complications, and outcomes, including reinterventions and tracheotomy dependence, are reported. RESULTS: Seventy-two patients (71 women; mean age, 50.4 years) with idiopathic subglottic stenosis requiring surgical airway intervention were identified. Six patients underwent tracheotomy prior to attempt at airway stenosis surgery. Initial surgical approach thereafter included endoscopic (73.5%, n = 53) and open (26.4%, n = 19) procedures. Thirty-one patients underwent cricotracheal resection; the reintervention rate was 22.5%. Sixty patients underwent 147 endoscopic procedures; the reintervention rate was 75.5%, and the mean time between dilations was 83 weeks (range, 5-402). Two (2.8%) patients remain tracheotomy dependent. Adverse events were significantly higher in the cricotracheal group, especially with respect to dysphonia and temporary gastrostomy tube placement (P < .01). CONCLUSIONS: Endoscopic and open surgical airway intervention can be employed successfully to avoid tracheotomy dependence and maintain airway patency; however, multiple procedures are usually required, regardless of surgical approach. Cricotracheal reintervention rates are lower than endoscopic dilation but with increased morbidity. Quality-of-life outcomes should be clearly discussed with patients before deciding on a surgical management strategy.

SABR-BRIDGE: Stereotactic ABlative Radiotherapy Before Resection to AvoId Delay for Early-Stage LunG Cancer or OligomEts During the COVID-19 Pandemic.

Surgical resection is the standard-of-care approach for early-stage non-small cell lung cancer (NSCLC). Surgery is also considered an acceptable standard infit patients with oligometastatic lesions in the lungs. The COVID-19 pandemic has led to worldwide issues with access to operating room time, with patients and physicians facing uncertainty as to when surgical resection will be available, with likely delays of months. Further compounding this are concerns about increased risks of respiratory complications with lung cancer surgery during active phases of the pandemic. In this setting, many thoracic oncology teams are embracing a paradigm where stereotactic ablative radiotherapy (SABR) is used as a bridge, to provide radical-intent treatment based on a combination of immediate SABR followed by planned surgery in 3-6 months. This pragmatic approach to treatment has been named SABR-BRIDGE (Stereotactic ABlative Radiotherapy Before Resection to avoId Delay for early-stage lunG cancer or oligomEts). This term has also been applied to the pragmatic study of the outcomes of this approach. In this paper, we discuss the standards of care in treatment of early-stage (NSCLC) and pulmonary oligometastases, the impetus for the SABR-BRIDGE approach, and the controversies surrounding assessment of pathological response to neo-adjuvant radiation therapy.

Measuring the Integration of Stereotactic Ablative Radiotherapy Plus Surgery for Early-Stage Non-Small Cell Lung Cancer: A Phase 2 Clinical Trial.

IMPORTANCE: Stereotactic ablative radiotherapy (SABR) is a standard treatment option in patients with medically inoperable early-stage non-small cell lung cancer (NSCLC), yet the pathologic complete response (pCR) rate after SABR is unknown. Neoadjuvant SABR in patients with cancer who are fit for resection has been hypothesized to improve local control and induce antitumor immune activity, potentially leading to better outcomes. OBJECTIVES: To determine the pCR rate after SABR and to assess oncologic and toxicity outcomes after a combined approach of neoadjuvant SABR followed by surgery. DESIGN, SETTING, AND PARTICIPANTS: A phase 2, single-arm trial, with patient accrual from September 30, 2014, to August 15, 2017 (median follow-up, 19 months), was performed at a tertiary academic cancer center. Patients 18 years or older with T1T2N0M0 NSCLC and good performance status, with adequate pulmonary reserve to undergo surgical resection, were studied. INTERVENTIONS: Patients underwent neoadjuvant SABR using a risk-adapted fractionation scheme followed by surgery 10 weeks later. MAIN OUTCOMES AND MEASURES: The pCR rate as determined by hematoxylin-eosin staining. RESULTS: Forty patients (mean [SD] age, 68 [8] years; 23 [58%] female) were enrolled. Thirty-five patients underwent surgery and were evaluable for the primary end point. The pCR rate was 60% (95% CI, 44%-76%). The 30- and 90-day postoperative mortality rates were both 0%. Grade 3 or 4 toxic effects occurred in 7 patients (18%). In patients receiving surgery, 2-year overall survival was 77% (95% CI, 48%-91%), local control was 100% (95% CI, not defined), regional control was 53% (95% CI, 22%-76%), and distant control was 76% (95% CI, 45%-91%). Quality of life did not decline after treatment, with no significant changes in mean Functional Assessment of Cancer Therapy for Lung-Trial Outcome Index score during the first year of follow-up. CONCLUSIONS AND RELEVANCE: The pCR rate after SABR for early-stage NSCLC was 60%, lower than hypothesized. The combined approach had toxic effects comparable to series of surgery alone, and there was no perioperative mortality. Further studies are needed to evaluate this combined approach compared with surgical resection alone. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02136355.

Assessment of tumour response after stereotactic ablative radiation therapy for lung cancer: A prospective quantitative hybrid 18 F-fluorodeoxyglucose-positron emission tomography and CT perfusion study.

INTRODUCTION: Stereotactic ablative radiotherapy (SABR) is a guideline-recommended treatment for inoperable stage I non-small cell lung cancer (NSCLC), but imaging assessment of response after SABR is difficult. The goal of this study was to evaluate imaging-based biomarkers of tumour response using dynamic 18 F-FDG-PET and CT perfusion (CTP). METHODS: Thirty-one patients with early-stage NSCLC participated in this prospective correlative study. Each underwent dynamic 18 F-FDG-PET/CTP studies on a PET/CT scanner pre- and 8 weeks post-SABR. The dynamic 18 F-FDG-PET measured the tumour SUVmax , SUVmean and the following parameters: K1 , k2 , k3 , k4 and Ki , all using the Johnson-Wilson-Lee kinetic model. CTP quantitatively mapped BF, BV, MTT and PS in tumours and measured largest tumour diameter. Since free-breathing was allowed during CTP scanning, non-rigid image registration of CT images was applied to minimize misregistration before generating the CTP functional maps. Differences between pre- and post-SABR imaging-based parameters were compared. RESULTS: Tumour size changed only slightly after SABR (median 26 mm pre-SABR vs. 23 mm post-SABR; P = 0.01). However, dynamic 18 F-FDG-PET and CTP study showed substantial and significant changes in SUVmax , SUVmean , k3 , k4 and Ki . Significant decreases were evident in SUVmax (median 6.1 vs. 2.6; P < 0.001), SUVmean (median 2.5 vs. 1.5; P < 0.001), k3 (relative decrease of 52%; P = 0.002), Ki (relative decrease of 27%; P = 0.03), whereas there was an increase in k4 (+367%; P < 0.001). CONCLUSIONS: Hybrid 18 F-FDG-PET/CTP allowed the response of NSCLC to SABR to be assessed regarding metabolic and functional parameters. Future studies are needed, with correlation with long-term outcomes, to evaluate these findings as potential imaging biomarkers of response.

The Potential Dangers of Recruitment Maneuvers During One Lung Ventilation Surgery.

BACKGROUND: Existing evidence regarding lung-protective ventilation (LPV) during one-lung ventilation (OLV) focuses on surrogate outcomes. Our objective was to assess whether an LPV protocol during OLV surgery is associated with reduced respiratory complications. MATERIALS AND METHODS: This was a matched control retrospective cohort study of patients undergoing pulmonary resection at a tertiary Canadian hospital. The experimental group (n = 50) was derived from primary data of two crossover RCTs, which utilized protocolized LPV strategies with varying levels of positive end-expiratory pressure and recruitment maneuvers. The control group was drawn from a prospectively maintained database; these patients received conventional nonprotocolized ventilation (2000-2010). Each experimental group patient was matched 1:1 with a control group patient with respect to clinically relevant variables (age, sex, diagnosis, smoking status, cardiovascular disease status, comorbidity, BMI, preoperative forced expiratory volume in 1 s, surgery type). Major respiratory complications were defined as composite of acute respiratory distress syndrome, need for new positive-pressure ventilation, and atelectasis requiring bronchoscopy. Paired and unpaired statistical tests were used. RESULTS: Patients appeared well matched. Major respiratory complications occurred in 8% (n = 4) and 2% (n = 1) of patients in experimental and control groups, respectively (P = 0.50). There was a trend toward increased mortality (4 versus 0, P = 0.06) with protocolized LPV. The patients who died had respiratory complications; one had acute respiratory distress syndrome and two had profound hypoxemia. CONCLUSIONS: There was a nonsignificant trend toward increased mortality with LPV during OLV. Although limited by a small sample size, our findings identify a potential danger to excessive recruitment maneuvers. Larger studies, with clinically important outcomes are needed to better define the risk/benefit trade-offs for LPV during OLV.

Toward Lung Tumor Localization based on Strain Variability of Lung Surface during Video-Assisted Thoracoscopic Surgery.

Tumor localization, especially in case of minimally invasive lung tumor resection surgery, is extremely challenging due to the continuous motion of the organ. This motion can be troublesome as it results in spatial discrepancy corresponding to preoperative and intraoperative tumor location. In order to characterize lung tissue stiffness for the purpose of lung tumor localization, in this paper, we present a novel characterization approach based on variability in resistance of the healthy region vs. the tumorous region resulting from lung motion. The proposed approach is numerically validated on a Finite Element (FE) model of the lung with varying surface stiffnesses, where higher stiffness represents tumor and lower stiffness corresponds to healthy lung tissue. The numerical simulation validates the sensitivity of our mechanism for different grades of tumors by demonstrating that the strain on the healthy tissue is 31.8 and 67.1 times higher than that on the tumor surface for a selected relative stiffness variation of 3.6x and 24.4x respectively, at a pressure of 1.6 KPa. Additionally, a framework is developed to validate the proposed approach in a video of a video-assisted thoracoscopic surgery (VATS), where multiple landmarks on the lung surface are tracked. This enables us to quantify the motion of points residing on healthy surface and tumorous surface. The motion data is further analyzed to study the relative surface strain, and it is shown that the proposed approach differentiates a tumor from healthy surface.

Use of lung-protective strategies during one-lung ventilation surgery: a multi-institutional survey.

BACKGROUND: Limited evidence suggests that intraoperative lung-protective ventilation (LPV) during one-lung ventilation (OLV) may reduce respiratory complications after thoracic surgery. Little is known about LPV practices during OLV. Our purpose was to assess the state of practice/perspectives of anesthesiologists regarding LPV during elective OLV. METHODS: We conducted a multi-institutional cross-sectional survey of anesthesiologists performing OLV at high-volume Canadian tertiary/university centers. The survey was designed, refined and distributed by a multi-disciplinary team using the Dillman method. Univariable and multivariable analyses were used. RESULTS: Seventy-five (63%) of 120 eligible respondents completed the survey. Although the critical care literature focuses on minimizing tidal volume (TV) as the central strategy of LPV, most respondents (89%, n=50/56) focused on minimizing peak airway pressure (PAP) as their primary strategy of intraoperative LPV. Only 64% (n=37/58) reported actively trying to minimize TV. While 32% (n=17/54) were unsure about the current evidence regarding LPV, 67% (n=36/54) believed that the evidence favoured their use during OLV. Perceived clinical and institutional barriers were the only predictors of reduced attempts to minimize TV on univariate analyses. In multivariable/adjusted analyses, perceived institutional barriers were the only predictors of reduced attempts to minimize TV with adjusted odds ratio of 0.1 (95% CI: 0.03-0.6). CONCLUSIONS: Most anesthesiologists defined low PAP as the primary strategy of LPV during OLV and attempted to minimize it. This study is the first to assess the practice/perspectives of anesthesiologists regarding LPV during OLV and also the first to explore predictors of LPV use. Randomized trials are currently ongoing. However, this study suggests that institutional barriers may subvert future knowledge translation and need to be addressed.

Development of an In Situ Thoracic Surgery Crisis Simulation Focused on Nontechnical Skill Training.

BACKGROUND: Our vision was to develop an inexpensive training simulation in a functional operating room (in situ) that included surgical trainees and nursing and anesthesia staff to focus on effective interprofessional communication and teamwork skills. METHODS: The simulation scenario revolved around an airway obstruction by residual tumor after pneumonectomy. This model included our thoracic operating room with patient status displayed by an open access vital sign simulator and a reversibly modified Laerdal airway mannequin (Shavanger, Norway). The simulation scenario was run seven times. Simulations were video recorded and scored with the use of Non-Technical Skills for Surgeons (NOTSS) and TeamSTEPPS2. Latent safety threats (LSTs) and feedback were obtained during the debriefing after the simulation. Feedback was captured with the Method Material Member Overall (MMMO) questionnaire. RESULTS: Several LSTs were identified, which included missing and redundant equipment and knowledge gaps in participants' roles. Consultant surgeons received a higher overall score than thoracic surgery fellows on both NOTSS (3.8 versus 3.3) and TeamSTEPPS2 (4.1 versus 3.2) evaluations, suggesting that the scenario effectively differentiated learners from experts with regards to nontechnical skills. The MMMO overall simulation experience score was 4.7 of 5, confirming a high-fidelity model and useful experiential learning model. At the Canadian Thoracic Bootcamp, the MMMO overall experience score was 4.8 of 5, further supporting this simulation as a robust model. CONCLUSIONS: An inexpensive in situ intraoperative crisis simulation model for thoracic surgical emergencies was created, implemented, and demonstrated to be effective as a proof of concept at identifying latent threats to patient safety and differentiating the nontechnical skills of trainees and consultant surgeons.

Developing a National, Simulation-Based, Surgical Skills Bootcamp in General Thoracic Surgery.

BACKGROUND: The use surgical simulation across all subspecialties has gained widespread adoption in the last decade. A number of factors, including the small number of trainees, identified gaps in surgical skill training from cross-sectional surveys, increased national collaboration, and support from the national specialty committee identified a need to construct a surgical skills "bootcamp" in thoracic surgery in Canada. OBJECTIVE: The goals of the surgical skills bootcamp, as identified by the residency training program directors and the national specialty committee were to create a national, centralized, simulation-based skills workshop that focused on key foundational procedures within thoracic surgery, particularly those identified as areas of weakness by former residents; to smooth the transition to intraoperative teaching; to provide exposure to important but not necessarily universally available procedures such as advanced endoscopy; to teach non-medical expert competencies, and lastly to provide a venue for networking for residents across the country. DESIGN: The curriculum committee has constructed a 3.5 day curriculum, with a focus on hands-on skills simulation, as well as lectures, on a breadth of topics including benign esophageal disorders, lung cancer staging, minimally invasive lung surgery, crisis management and advanced bronchoscopy and endoscopy. All residents across the country attend as well as faculty from a variety of institutions. SETTING: The course is hosted centrally at the University of Toronto, Ontario over 3.5 days. A combination of auditorium and both animal and human operating room facilities are utilized. METHODS: A needs-assessment based on a formal meeting of the program directors, as well feedback from surveys identified the target areas for curriculum development. A committee of interested faculty developed the content as well as the local construct and logistics required. Iterative feedback has evolved the duration and content over the initial 3 years. RESULTS: Through formal resident feedback, national subspecialty committee review, and program director meetings the support for the bootcamp has been overwhelmingly positive. Specific resident feedback for structure, content and specific simulations has been favorable, but has also been used to modify the program. CONCLUSION: In response to identified weaknesses in training, with the support of the national specialty committee, the residency program directors, and the faculty at the University of Toronto, an intensive simulation based thoracic surgery bootcamp has successfully been created for Canadian thoracic surgery residents.

Staging and surgical approaches in gastric cancer: A systematic review.

BACKGROUND: Gastric adenocarcinoma accounted for 6.8% of new cancer cases and 8.8% of cancer deaths worldwide in 2012. Although resection is the cornerstone for cure, several aspects of surgical intervention remain controversial or sub-optimally applied at the population level. These include staging, extent of lymph node dissection (LND), optimal requirements of LN assessment, minimum resection margins, surgical technique (laparoscopic vs. open), relationship between surgical volumes and patient outcomes, and resection of stage IV gastric cancer. METHODS: A systematic review was conducted to inform surgical care. RESULTS: The evidence included in this systematic review consists of one guideline, seven systematic reviews and 48 primary studies. CONCLUSIONS: All patients should be discussed at a multidisciplinary team meeting and a staging CT of the chest and abdomen should always be performed. Diagnostic laparoscopy should be performed in patients at risk for stage IV disease. A D2 LND is preferred for curative-intent resection in advanced non-metastatic gastric cancer. At least 16 LNs should be assessed for adequate staging of curative-resected gastric cancer. Gastric cancer surgery should aim to achieve an RO resection margin. In the metastatic setting, surgery should only be considered for palliation of symptoms. Patients should be referred to higher volume centres, and those with adequate support to manage potential complications. Laparoscopic resections should be performed to the same standards as open resections.