Staging laparoscopy with peritoneal lavage to identify peritoneal metastases and free intraperitoneal cancer cells in the management of locally advanced gastric cancer

INTRODUCTION

Gastric cancer often presents in advanced stage with a significant risk for peritoneal dissemination. Staging laparoscopy can be used to detect peritoneal carcinomatosis (PC+) and free cancer cells in peritoneal lavage cytology (CY+). The current study aimed to present the outcomes of staging laparoscopy and the prognosis of PC+ and CY+ in a Swedish high-volume center.

MATERIALS AND METHODS

A cohort study including all consecutive patients with locally advanced gastric cancer who underwent staging laparoscopy between February 2008 and October 2022. The laparoscopy findings were categorized as PC+, PC-CY+ (positive cytology without peritoneal carcinomatosis) or negative laparoscopy (PC-CY-). The primary endpoint was overall survival (OS) stratified by laparoscopy findings. The secondary endpoint was OS within each laparoscopy finding group stratified by subsequent treatment.

RESULTS

Among 168 patients who underwent staging laparoscopy, 78 patients (46%) had PC-CY-, 29 patients (17%) had PC-CY+ and 61 patients (36%) had PC+. Decreased OS was observed for both PC-CY+ patients (aHR 2.14, 95% CI 1.13-4.06) and PC+ patients (aHR 5.36, 95% CI 3.21-8.93), compared to PC-CY-. Patients with PC-CY+ who converted to PC-CY- after chemotherapy and underwent tumor resection seemed to have a better prognosis compared to patients with persisting PC-CY+.

CONCLUSIONS

Staging laparoscopy is an important tool in the staging of locally advanced gastric cancer. Tumor resection for patients with PC-CY+ who convert to PC-CY- may lead to improved survival for these patients.

Solvent Suppression in Pure Shift NMR

Intense solvent signals in 1H solution-state NMR experiments typically cause severe distortion of spectra and mask nearby solute signals. It is often infeasible or undesirable to replace a solvent with its perdeuterated form, for example, when analyzing formulations in situ, when exchangeable protons are present, or for practical reasons. Solvent signal suppression techniques are therefore required. WATERGATE methods are well-known to provide good solvent suppression while enabling retention of signals undergoing chemical exchange with the solvent signal. Spectra of mixtures, such as pharmaceutical formulations, are often complicated by signal overlap, high dynamic range, the narrow spectral width of 1H NMR, and signal multiplicity. Here, we show that by combining WATERGATE solvent suppression with pure shift NMR, ultrahigh-resolution 1H NMR spectra can be acquired while suppressing intense solvent signals and retaining exchangeable 1H signals. The new method is demonstrated in the analysis of cyanocobalamin, a vitamin B12 supplement, and of an eye-drop formulation of atropine.

Diagnostic workup for esophageal cancer patients can be improved with checklists and clearer protocols; a comparative study between two tertiary centers in Europe

BACKGROUND

Rapid and complete workup of newly diagnosed esophageal cancer is vital for a timely, individual and high-quality treatment strategy. The aim of this study was to uncover potential delay, inefficiencies and non-contributing investigations in the diagnostic process in two tertiary referral centers.

METHODS

This retrospective cohort study included all newly diagnosed esophageal cancer patients referred to or diagnosed in the Amsterdam UMC and Karolinska University Hospital between July 2020 and July 2021. Radiology, pathological assessment and multidisciplinary team meeting reports were reviewed. To assess time interval from diagnosis to treatment, dates of diagnosis, admittance to referral hospital, MDT meeting and start of treatment were collected.

RESULTS

In total, 252 esophageal cancer patients were included, 187 were treated with curative intent. Curatively treated patients had a mean age of 66 years, were predominantly male (74.9 %) with an adenocarcinoma (71.1 %). Curatively treated patients had a median time from diagnosis to referral of seven days (IQR:0-11) and of 35 days (IQR:28-45) between diagnosis and start of treatment. Main reasons for the significant (P < 0.001) differences in time between diagnosis and treatment between centers, Amsterdam UMC (39 days) vs Karolinska (27 days), were need for additional diagnostics (47.8 %) and differences in referral routine. Gastroscopy was repeated in 32.2 % of patients, mainly for further anatomical mapping.

CONCLUSION

Significant time differences between centers in the path from diagnosis to start treatment can be explained by differences in workup approach, referral routines and MDT meeting regulations. Repeat of gastroscopy can be prevented with clearer endoscopy guidelines.

Major Intraoperative Complications During Minimally Invasive Esophagectomy

BACKGROUND

Studies have shown minimally invasive esophagectomy (MIE) to be a feasible surgical technique in treating esophageal carcinoma. Postoperative complications have been extensively reviewed, but literature focusing on intraoperative complications is limited. The main objective of this study was to report major intraoperative complications and 90-day mortality during MIE for cancer.

METHODS

Data were collected retrospectively from 10 European esophageal surgery centers. All intention-to-treat, minimally invasive laparoscopic/thoracoscopic esophagectomies with gastric conduit reconstruction for esophageal and GE junction cancers operated on between 2003 and 2019 were reviewed. Major intraoperative complications were defined as loss of conduit, erroneous transection of vascular structures, significant injury to other organs including bowel, heart, liver or lung, splenectomy, or other major complications including intubation injuries, arrhythmia, pulmonary embolism, and myocardial infarction.

RESULTS

Amongst 2862 MIE cases we identified 98 patients with 101 intraoperative complications. Vascular injuries were the most prevalent, 41 during laparoscopy and 19 during thoracoscopy, with injuries to 18 different vessels. There were 24 splenic vascular or capsular injuries, 11 requiring splenectomies. Four losses of conduit due to gastroepiploic artery injury and six bowel injuries were reported. Eight tracheobronchial lesions needed repair, and 11 patients had significant lung parenchyma injuries. There were 2 on-table deaths. Ninety-day mortality was 9.2%.

CONCLUSIONS

This study offers an overview of the range of different intraoperative complications during minimally invasive esophagectomy. Mortality, especially from intrathoracic vascular injuries, appears significant.

Oncological outcomes of standard versus prolonged time to surgery after neoadjuvant chemoradiotherapy for oesophageal cancer in the multicentre, randomised, controlled NeoRes II trial

BACKGROUND

The optimal time to surgery (TTS) after neoadjuvant chemoradiotherapy (nCRT) for oesophageal cancer is unknown and has traditionally been 4-6 weeks in clinical practice. Observational studies have suggested better outcomes, especially in terms of histological response, after prolonged delay of up to 3 months after nCRT. The NeoRes II trial is the first randomised trial to compare standard to prolonged TTS after nCRT for oesophageal cancer.

PATIENTS AND METHODS

Patients with resectable, locally advanced oesophageal cancer were randomly assigned to standard delay of surgery of 4-6 weeks or prolonged delay of 10-12 weeks after nCRT. The primary endpoint was complete histological response of the primary tumour in patients with adenocarcinoma (AC). Secondary endpoints included histological tumour response, resection margins, overall and progression-free survival in all patients and stratified by histologic type.

RESULTS

Between February 2015 and March 2019, 249 patients from 10 participating centres in Sweden, Norway and Germany were randomised: 125 to standard and 124 to prolonged TTS. There was no significant difference in complete histological response between AC patients allocated to standard (21%) compared to prolonged (26%) TTS (P = 0.429). Tumour regression, resection margins and number of resected lymph nodes, total and metastatic, did not differ between the allocated interventions. The first quartile overall survival in patients allocated to standard TTS was 26.5 months compared to 14.2 months after prolonged TTS (P = 0.003) and the overall risk of death during follow-up was 35% higher after prolonged delay (hazard ratio 1.35, 95% confidence interval 0.94-1.95, P = 0.107).

CONCLUSION

Prolonged TTS did not improve histological complete response or other pathological endpoints, while there was a strong trend towards worse survival, suggesting caution in routinely delaying surgery for >6 weeks after nCRT.

Pure shift FESTA: An ultra-high resolution NMR tool for the analysis of complex fluorine-containing spin systems

NMR measurements of molecules containing sparse fluorine atoms are becoming increasingly common due to their prevalence in medicinal chemistry. However, the presence of both homonuclear and heteronuclear scalar couplings severely complicates their analysis by NMR. In complex systems, FESTA, a heteronuclear spectral editing method, allows simplified 1 H NMR spectra to be obtained containing only 1 H signals from the same spin system as a chosen 19 F. Despite spectral simplification, signal overlap due to the presence of scalar couplings is often a problem in FESTA spectra. Here, we report a new experiment that combines FESTA and pure shift methods to provide fully decoupled ultra-high resolution FESTA spectra showing a single signal for each 1 H chemical environment. The utility of the method is demonstrated for the analysis of two complex fluorine-containing mixtures of pharmaceutical and biochemical interest.

Recovering sensitivity lost through convection in pure shift NMR

Practical pure shift NMR experiments, especially on instruments equipped with cryoprobes, can sometimes give very disappointing results. Here we show for the first time that this is a consequence of signal loss due to sample convection, and demonstrate a simple adjustment to common pure shift NMR experiments that restores the lost signal.

Lighting up spin systems: enhancing characteristic 1H signal patterns of fluorinated molecules

Fluorine is becoming increasingly prevalent in medicinal chemistry, both in drug molecules and in molecular probes. The presence of fluorine allows convenient monitoring of such molecules in complex environments by NMR spectroscopy. However, sensitivity is a persistent limitation of NMR, especially when molecules are present at low concentrations. Here, sensitivity issues with 1H NMR are mitigated by sharing 19F photochemically-induced dynamic nuclear polarisation with 1H nuclei. Unlike direct 1H enhancement, this method enhances 1H signals without significantly distorting multiplet intensities, and has the potential to enable the use of suitable molecules as low-concentration probes.

Predictive value of diffusion MRI-based parametric response mapping for prognosis and treatment response in glioblastoma

BACKGROUND

Early detection of treatment response is important for the management of patients with malignant brain tumors such as glioblastoma to assure good quality of life in relation to therapeutic efficacy.

AIM

To investigate whether parametric response mapping (PRM) with diffusion MRI may provide prognostic information at an early stage of standard therapy for glioblastoma.

MATERIALS AND METHODS

This prospective study included 31 patients newly diagnosed with glioblastoma WHO grade IV, planned for primary standard postoperative treatment with radiotherapy 60Gy/30 fractions with concomitant and adjuvant Temozolomide. MRI follow-up including diffusion and perfusion weighting was performed at 3 T at start of postoperative chemoradiotherapy, three weeks into treatment, and then regularly until twelve months postoperatively. Regional mean diffusivity (MD) changes were analyzed voxel-wise using the PRM method (MD-PRM). At eight and twelve months postoperatively, after completion of standard treatment, patients were classified using conventional MRI and clinical evaluation as either having stable disease (SD, including partial response) or progressive disease (PD). It was assessed whether MD-PRM differed between patients having SD versus PD and whether it predicted the risk of disease progression (progression-free survival, PFS) or death (overall survival, OS). A subgroup analysis was performed that compared MD-PRM between SD and PD in patients only undergoing diagnostic biopsy. MGMT-promotor methylation status (O6-methylguanine-DNA methyltransferase) was registered and analyzed with respect to PFS, OS and MD-PRM.

RESULTS

Of the 31 patients analyzed: 21 were operated by resection and ten by diagnostic biopsy. At eight months, 19 patients had SD and twelve had PD. At twelve months, ten patients had SD and 20 had PD, out of which ten were deceased within twelve months and one was deceased without known tumor progression. Median PFS was nine months, and median OS was 17 months. Eleven patients had methylated MGMT-promotor, 16 were MGMT unmethylated, and four had unknown MGMT-status. MD-PRM did not significantly predict patients having SD versus PD neither at eight nor at twelve months. Patients with an above median MD-PRM reduction had a slightly longer PFS (P = 0.015) in Kaplan-Maier analysis, as well as a non-significantly longer OS (P = 0.099). In the subgroup of patients only undergoing biopsy, total MD-PRM change at three weeks was generally higher for patients with SD than for patients with PD at eight months, although no tests were performed. MGMT status strongly predicted both PFS and OS but not MD-PRM change.

CONCLUSION

MD-PRM at three weeks was not demonstrated to be predictive of treatment response, disease progression, or survival. Preliminary results suggested a higher predictive value in non-resected patients, although this needs to be evaluated in future studies.

Rapid Measurement of Heteronuclear Coupling Constants in Complex NMR Spectra

The NMR analysis of fluorine-containing molecules, increasingly widespread due to their importance in pharmaceuticals and biochemistry, poses significant challenges. Severe peak overlap in the proton spectrum often hinders the extraction of critical structural information in the form of heteronuclear scalar coupling constants, which are crucial for determining pharmaceutical properties and biological activity. Here, a new method, IPAP-FESTA, is reported that drastically simplifies measurements of the signs and magnitudes of proton-fluorine couplings. Its usefulness is demonstrated for the structural study of the steroidal drug fluticasone propionate extracted from a commercial formulation and for assessing solvent effects on the conformational equilibrium in a physically inseparable fluorohydrin mixture.

Ultra-selective 1D clean in-phase correlation spectroscopy

Selective 1D COSY can unambiguously identify coupled spins but is often limited both by lack of selectivity, and by unfavourable multiplet lineshapes. Here, ultra-selective GEMSTONE excitation is employed with CLIP-COSY to provide through-bond correlations for nuclei whose NMR signals overlap. The new method is illustrated using the coccidiostat lasalocid and the immunosuppressant cyclosporin.

Resolving the complexity in human milk oligosaccharides using pure shift NMR methods and CASPER

Human milk oligosaccharides belong to an important class of bioactive molecules with diverse effects on the development of infants. NMR is capable of providing vital structural information about oligosaccharides which can aid in determining structure-function relationships. However, this information is often concealed by signal overlap in ¹H spectra, due to the narrow chemical shift range and signal multiplicity. Signal overlap in oligosaccharide spectra can be greatly reduced, and resolution improved, by utilising pure shift methods. Here the benefits of combining pure shift methods with the CASPER computational approach to resonance assignment in oligosaccharides are demonstrated.

Feasibility and Safety of Laparoscopic D2 Gastrectomy in Combination with Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) in Patients with Gastric Cancer at High Risk of Recurrence-The PIPAC-OPC4 Study

BACKGROUND

Patients with gastric adenocarcinoma (GAC) are at high risk of peritoneal recurrence despite perioperative chemotherapy and radical resection. This study evaluated feasibility and safety of laparoscopic D2 gastrectomy in combination with pressurized intraperitoneal aerosol chemotherapy (PIPAC).

METHODS

This was a prospective, controlled bi-institutional study in patients with GAC at high risk of recurrence treated with PIPAC with cisplatin and doxorubicin (PIPAC C/D) after laparoscopic D2 gastrectomy. High risk was defined as a poorly cohesive subtype with predominance of signet-ring cells, clinical stage ≥ T3 and/or ≥ N2, or positive peritoneal cytology. Peritoneal lavage fluid was collected before and after resection. Cisplatin (10.5 mg/m²) and doxorubicin (2.1 mg/m²) were aerosolized after anastomosis (flow 0.5-0.8 ml/s, maximum pressure 300 PSI). Treatment was feasible and safe if ≤ 20% had Dindo-Clavien ≥ 3b surgical complications or CTCAE ≥ 4 medical adverse events within 30 days. Secondary outcomes were length of stay (LOS), peritoneal lavage cytology, and completion of postoperative systemic chemotherapy.

RESULTS

Twenty-one patients were treated with a D2 gastrectomy and PIPAC C/D. The median age was 61 years (range 24-76), there were eleven female patients, and 20 patients had preoperative chemotherapy. There was no mortality. Two patients had grade 3b complications that were potentially related to PIPAC C/D (one anastomotic leakage, and one late duodenal blow-out). One patient had severe neutropenia, and nine patients had moderate pain. The LOS was 6 days (4-26). One patient had positive peritoneal lavage cytology before resection, and none were positive after. Fifteen patients had postoperative chemotherapy.

CONCLUSIONS

Laparoscopic D2 gastrectomy in combination with PIPAC C/D is feasible and safe.

ERAS guidelines-driven upper gastrointestinal contrast study after esophagectomy can detect delayed gastric conduit emptying and improve outcomes

BACKGROUND

Delayed gastric conduit emptying can occur after esophagectomy and has been shown to be associated with increased risk for postoperative complications. Application of a standardized clinical protocol after esophagectomy including an upper gastrointestinal contrast study has the potential to improve postoperative outcomes.

METHODS

Prospective cohort including all patients operated with esophagectomy at two high-volume centers for esophageal surgery. The standardized clinical protocol included an upper gastrointestinal contrast study on day 2 or 3 after surgery. All images were compiled and evaluated for the purpose of the study. Clinical data was collected in IRB approved institutional databases at the participating centers.

RESULTS

The study included 119 patients treated with esophagectomy of whom 112 (94.1%) completed an upper gastrointestinal contrast study. The results showed that 8 (7.1%) patients had radiological delayed gastric conduit emptying defined as no emptying of contrast through the pylorus. Partial conduit emptying was seen in 34 (30.4%) patients, and 70 (62.5%) patients had complete conduit emptying. Complete or partial emptying was associated with significantly earlier nasogastric tube removal (3 vs. 6 days) and hospital discharge 8 vs. 17 days, P < 0.001). Radiological signs of delayed gastric conduit emptying were shown to be associated with increased risk of postoperative complications. There was, however, no association with severe postoperative complications according to Clavien-Dindo score, pulmonary complications, anastomotic leak or need for intensive care.

CONCLUSION

The results of the study demonstrate that postoperative upper gastrointestinal contrast studies can be used to assess the level of emptying of the gastric conduit after esophagectomy. Application of upper gastrointestinal contrast study in the ERAS guidelines-driven standardized clinical pathway after esophagectomy has the potential to improve postoperative outcomes.

Ultra-selective, ultra-clean 1D rotating-frame Overhauser effect spectroscopy

An ultra-selective 1D NMR experiment – GEMSTONE-ROESY – enables clear, unambiguous assignment of ROE signals in the not uncommon situation that traditional selective methods fail. Its usefulness is demonstrated in...

Relaxational signal attenuation during soft refocusing pulses

Quantitative NMR is widely used, but the systematic errors introduced when signals are excited by anything other than a single hard pulse are not always well understood. One important source of error in experiments using soft pulses is the spin relaxation that takes place during pulses, which contains contributions from both spin-spin and spin-lattice relaxation. Here it is shown that relaxation on resonance during shaped soft 180° refocusing pulses in practical experiments can be well represented by biexponential decay, with rate constants R₂ and a shape-dependent linear combination of R₁ and R₂, where R₁ and R₂ are the inverses of the spin-lattice and spin-spin relaxation times T₁ and T₂. In principle this would allow correction for relaxational losses in experiments using on-resonance selective refocusing pulses.

Identification of Distinct Soluble States During Fibril Formation Using Multilinear Analysis of NMR Diffusion Data

Protein misfolding and self-assembling into amyloid structures are associated with a number of diseases. Characterization of protein amyloid formation reactions is a challenging task as transient populations of multiple species are involved. Here we outline a method for identification and characterization of the individual soluble states during protein amyloid formation. The method combines NMR translational diffusion measurements with multilinear data analysis.

Simultaneous Broadband Suppression of Homonuclear and Heteronuclear Couplings in 1 H NMR Spectroscopy

The ¹ H NMR analysis of species containing NMR-active heteronuclei can be difficult due to signal overlap caused by the combined effects of homonuclear and heteronuclear scalar (J) couplings. Here, a general pure shift method is presented for obtaining ultra-high resolution ¹ H NMR spectra where spectral overlap is drastically reduced by suppressing both homonuclear and heteronuclear J-couplings, giving one single signal per ¹ H chemical environment. Its usefulness is demonstrated in the analysis of fluorine- and phosphorus-containing compounds of pharmaceutical and biochemical interest.

Giving Pure Shift NMR Spectroscopy a REST─Ultrahigh-Resolution Mixture Analysis

Most interesting problems in chemistry, biology, and pharmacy involve mixtures. However, analysis of such mixtures by NMR remains a challenge, often requiring the mixture components to be physically separated before analysis. A variety of methods have been proposed that exploit species-specific properties such as diffusion and relaxation to distinguish between the signals of different components in a mixture without the need for laborious separation. However, these methods can struggle to distinguish between components when signals overlap. Here, we exploit the relaxation properties of selected nuclei to distinguish between different components of a mixture while using pure shift methods to increase spectral resolution by up to an order of magnitude, greatly reducing signal overlap. The advantages of the new method are demonstrated in a mixture of d-xylose and l-arabinose, distinguishing unambiguously between the five major species present.

JS04.6.A The landscape of tumor cell states and spatial organization in H3-K27M mutant diffuse midline glioma across age and location

Background

Histone 3 lysine27-to-methionine mutations (H3-K27M) frequently occur in childhood diffuse midline gliomas (DMGs) of the pons, thalamus and spinal cord, presumed to be driven by the specific spatiotemporal context of these midline locations during postnatal development. While most common in the pons and at mid-childhood ages, the same oncohistone mutation is recurrently detected in adult DMGs and throughout different midline regions. The potential heterogeneity of tumors at different ages and in different anatomical locations of the midline are vastly understudied.

Material and Methods

Through dissecting the transcriptomic, epigenomic and spatial architectures of a comprehensive cohort of patient H3-K27M DMGs - spanning the age range from 2-68 years and locations from spinal cord to thalamus - at single cell resolution, we delineate how age- and location-dependent contexts shape glioma cell-intrinsic and -extrinsic features in light of the shared driver mutation.

Results

We identify that oligodendrocyte precursor (OPC)-like cells constitute the stem-like compartment in H3-K27M DMGs across all clinico-anatomical groups, however, depending on location, display varying levels of maturity resembling less differentiated pre-OPCs or more mature OPCs further differentiated along the oligodendroglial lineage. We further demonstrate increased mesenchymal cell states in adult tumors, which we link to age-related differences in glioma-associated immune cell compartments. We for the first time resolve the spatial organization of H3-K27M DMG cell types in intact patient tissues, identifying a local niche of the oligodendroglial lineage.

Conclusion

Our study provides a powerful resource for rational modeling and therapeutic frameworks taking into account determinants of age and location in this lethal glioma group.

Severity of oEsophageal Anastomotic Leak in patients after oesophagectomy: the SEAL score

Background

Anastomotic leak (AL) is a common but severe complication after oesophagectomy. It is unknown how to determine the severity of AL objectively at diagnosis. Determining leak severity may guide treatment decisions and improve future research. This study aimed to identify leak-related prognostic factors for mortality, and to develop a Severity of oEsophageal Anastomotic Leak (SEAL) score.

Methods

This international, retrospective cohort study in 71 centres worldwide included patients with AL after oesophagectomy between 2011 and 2019. The primary endpoint was 90-day mortality. Leak-related prognostic factors were identified after adjusting for confounders and were included in multivariable logistic regression to develop the SEAL score. Four classes of leak severity (mild, moderate, severe, and critical) were defined based on the risk of 90-day mortality, and the score was validated internally.

Results

Some 1509 patients with AL were included and the 90-day mortality rate was 11.7 per cent. Twelve leak-related prognostic factors were included in the SEAL score. The score showed good calibration and discrimination (c-index 0.77, 95 per cent c.i. 0.73 to 0.81). Higher classes of leak severity graded by the SEAL score were associated with a significant increase in duration of ICU stay, healing time, Comprehensive Complication Index score, and Esophagectomy Complications Consensus Group classification.

Conclusion

The SEAL score grades leak severity into four classes by combining 12 leak-related predictors and can be used to the assess severity of AL after oesophagectomy.

SABRE-enhanced real-time pure shift NMR spectroscopy

Pure shift nuclear magnetic resonance (NMR) methods suppress the effect of homonuclear scalar couplings to produce NMR spectra consisting solely of a single signal for each chemically distinct site. They are increasingly relied upon for analysis of complex molecules and mixtures as they overcome the extensive signal overlap that complicates proton NMR spectra of all but the simplest species. Current broadband pure shift methodologies for 1D proton spectra suffer from reduced sensitivity compared with their conventional counterparts and typically require a large amount of instrument time for low concentration samples. In this study, we demonstrate how the sensitivity limitation may be overcome by transiently increasing the bulk polarization using signal amplification by reversible exchange (SABRE) hyperpolarization. We utilize para-enriched dihydrogen to enhance the pure shift NMR resonances of pyridine by up to a factor of 60 in a single-scan experiment and extend this to propose a method to unambiguously determine mixture components based on the enhancement of their pure shift NMR signals.

Mentorship during undergraduate surgical training: comparing perceptions of medical students and faculty at two institutions in South Africa and Sweden

BACKGROUND

Having a mentor during undergraduate surgical training has been shown to positively influence medical students by increasing interest in surgery, improving confidence, and assisting in career planning. This study aimed to evaluate and compare medical student and faculty perceptions of mentorship during undergraduate surgical training and compare results between two teaching institutions in South Africa and Sweden.

METHODS

An electronic, online questionnaire was anonymously distributed to medical students and general surgical faculty at the University of Cape Town (UCT), South Africa, and Karolinska Institutet (KI), Stockholm, Sweden. The questionnaire consisted of multiple choice, true or false, and five-point Likert scale questions, exploring perceptions of mentorship and role models, as well as rating the most important mentor characteristics.

RESULTS

Approximately one third (34.2%) of students stated they had a mentor during their surgical training, with significant differences found between student cohorts (p < 0.001). The 'registrar' was most commonly reported as the best role model for medical students by faculty from both UCT (50.0%) and KI (69.4%), as well as UCT students (36.6%). Students rated the following mentor qualities significantly higher compared to faculty: student encouragement (p = 0.037), adequate supervision (p = 0.007), setting of fair expectations (p = 0.002), and teaching skills (p = 0.010).

CONCLUSION

With significant differences existing in the perceptions of medical students and faculty regarding mentorship and role models during undergraduate surgical training in both South African and Swedish institutions, reconciling and harmonising these differences will be crucial in fostering constructive mentoring relationships.

Effect of SGLT2 inhibition on coronary microvascular function in patients with type 2 diabetes

Background

Treatment with sodium-glucose cotransporter 2 (SGLT2) inhibitor reduces risk of cardiovascular death and heart failure but the underlying mechanisms remain poorly understood. It has been suggested that a shift in fuel source in the myocardium from glucose and free fatty acids to the more energy efficient ketogenesis reduces oxidative stress involved in coronary microvascular damage, leading to improved coronary microvascular function.

Purpose

To test the hypothesis that treatment with the SGLT2 inhibitor empagliflozin improves non-endothelial dependent coronary microvascular function.

Methods

We included 26 patients with type 2 diabetes in a double blinded, placebo-controlled cross-over study. Participants were treated with empagliflozin 25 mg and placebo for 12 weeks, interrupted by 2 weeks wash-out period. The primary outcome was change in coronary microvascular function, assessed as coronary flow velocity reserve (CFVR) and measured with transthoracic doppler echocardiography. Secondary endpoints were change in echocardiographic parameters of cardiac systolic function and 184 cardiovascular protein biomarkers.

Results

Nineteen patients completed both study periods according to protocol. There was a significant weight loss and reduction in Hba1c after empagliflozin treatment (table). We found no improvement in CFVR and parameters of cardiac systolic function. We observed a general tendency of reduction in level of cardiovascular biomarkers after empagliflozin treatment (figure) with significant difference between empagliflozin and placebo for 27 proteins, including IL18, ST2, YKL40, ACE2 and leptin.

Conclusions

Despite a significant weight loss and reduction in Hba1c after empagliflozin treatment, we found no effect on non-endothelial dependent coronary microvascular function in patients with type 2 diabetes mellitus. Improvement in multiple biomarkers may indicate underlying mechanisms but need confirmation in larger studies.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Danish Council for Independent Research Table 1. Change in outcome parametersFigure 1. Change in biomarker levels

Signal-to-noise ratio in diffusion-ordered spectroscopy: how good is good enough?

Diffusion-ordered NMR spectroscopy (DOSY) constructs multidimensional spectra displaying signal strength as a function of Larmor frequency and of diffusion coefficient from experimental measurements using pulsed field gradient spin or stimulated echoes. Peak positions in the diffusion domain are determined by diffusion coefficients estimated by fitting experimental data to some variant of the Stejskal-Tanner equation, with the peak widths determined by the standard error estimated in the fitting process. The accuracy and reliability of the diffusion domain in DOSY spectra are therefore determined by the uncertainties in the experimental data and thus in part by the signal-to-noise ratio of the experimental spectra measured. Here the Cramér-Rao lower bound, Monte Carlo methods, and experimental data are used to investigate the relationship between signal-to-noise ratio, experimental parameters, and diffusion domain accuracy in 2D DOSY experiments. Experimental results confirm that sources of error other than noise put an upper limit on the improvement in diffusion domain accuracy obtainable by time averaging.

Incidence, detection and outcome of differentiated thyroid cancer in Western Sweden

Background

It is unclear whether the increasing incidence of thyroid cancer (TC) due to increased diagnosis of small and indolent tumours might mask a real increase of clinically significant cancers. The aim of this study was to correlate surgery, pathology and outcome data of individual patients to the mode of primary detection (palpation, by imaging or incidental) to assess if TC incidence has increased.

Methods

The Swedish Cancer Registry identified all patients with TC in Västra Götaland County representing approximately 1.6 million inhabitants. Clinical information was retrieved from medical records of patient cohorts from three study intervals (2001–2002, 2006–2007 and 2011–2014) comprising 60 per cent of all TC patients. Data were also obtained from the NORDCAN registry to compare of TC incidence with other Nordic countries.

Results

Between 2001 and 2014, the annualized standard incidence rate/100 000 population (ASR) of TC increased from 3.14 to 10.71 in women and from 1.12 to 3.77 in men. This was higher than the mean incidence for Sweden but similar to that in Norway and Finland. Differentiated TC (DTC) increased more than threefold. The majority of tumours (64 per cent) were detected by palpation. Larger tumours (10–20, 21–40 and greater than 40 mm) increased as much as microcarcinomas (less than 10 mm). Only 5 per cent of the tumours were detected by imaging. All disease-specific deaths (8.5 per cent of DTC in the first two cohorts) and most patients with recurrent or persistent disease (6.6 per cent of DTC cases) were diagnosed due to tumour-related symptoms.

Conclusion

DTC in Western Sweden gradually increased between 2001 and 2014. The majority of tumours were detected by palpation suggesting a real increase in the incidence of clinically significant thyroid malignancies.

Broadband measurement of true transverse relaxation rates in systems with coupled protons: application to the study of conformational exchange

Accurate measurement of transverse relaxation rates in coupled spin systems is important in the study of molecular dynamics, but is severely complicated by the signal modulations caused by scalar couplings in spin echo experiments. The most widely used experiments for measuring transverse relaxation in coupled systems, CPMG and PROJECT, can suppress such modulations, but they also both suppress some relaxation contributions, and average relaxation rates between coupled spins. Here we introduce a new experiment which for the first time allows accurate broadband measurement of transverse relaxation rates of coupled protons, and hence the determination of exchange rate constants in slow exchange from relaxation measurements. The problems encountered with existing methods are illustrated, and the use of the new method is demonstrated for the classic case of hindered amide rotation and for the more challenging problem of exchange between helical enantiomers of a gold(i) complex.

Fit-for-Discharge Criteria after Esophagectomy: An International Expert Delphi Consensus

There are no internationally recognized criteria available to determine preparedness for hospital discharge after esophagectomy. This study aims to achieve international consensus using Delphi methodology. The expert panel consisted of 40 esophageal surgeons spanning 16 countries and 4 continents. During a 3-round, web-based Delphi process, experts voted for discharge criteria using 5-point Likert scales. Data were analyzed using descriptive statistics. Consensus was reached if agreement was ≥75% in round 3. Consensus was achieved for the following basic criteria: nutritional requirements are met by oral intake of at least liquids with optional supplementary nutrition via jejunal feeding tube. The patient should have passed flatus and does not require oxygen during mobilization or at rest. Central venous catheters should be removed. Adequate analgesia at rest and during mobilization is achieved using both oral opioid and non-opioid analgesics. All vital signs should be normal unless abnormal preoperatively. Inflammatory parameters should be trending down and close to normal (leucocyte count ≤12G/l and C-reactive protein ≤80 mg/dl). This multinational Delphi survey represents the first expert-led process for consensus criteria to determine 'fit-for-discharge' status after esophagectomy. Results of this Delphi survey may be applied to clinical outcomes research as an objective measure of short-term recovery. Furthermore, standardized endpoints identified through this process may be used in clinical practice to guide decisions regarding patient discharge and may help to reduce the risk of premature discharge or prolonged admission.

Patient-reported outcomes after oesophagectomy in the multicentre LASER study

BACKGROUND

Data on the long-term symptom burden in patients surviving oesophageal cancer surgery are scarce. The aim of this study was to identify the most prevalent symptoms and their interactions with health-related quality of life.

METHODS

This was a cross-sectional cohort study of patients who underwent oesophageal cancer surgery in 20 European centres between 2010 and 2016. Patients had to be disease-free for at least 1 year. They were asked to complete a 28-symptom questionnaire at a single time point, at least 1 year after surgery. Principal component analysis was used to assess for clustering and association of symptoms. Risk factors associated with the development of severe symptoms were identified by multivariable logistic regression models.

RESULTS

Of 1081 invited patients, 876 (81.0 per cent) responded. Symptoms in the preceding 6 months associated with previous surgery were experienced by 586 patients (66.9 per cent). The most common severe symptoms included reduced energy or activity tolerance (30.7 per cent), feeling of early fullness after eating (30.0 per cent), tiredness (28.7 per cent), and heartburn/acid or bile regurgitation (19.6 per cent). Clustering analysis showed that symptoms clustered into six domains: lethargy, musculoskeletal pain, dumping, lower gastrointestinal symptoms, regurgitation/reflux, and swallowing/conduit problems; the latter two were the most closely associated. Surgical approach, neoadjuvant therapy, patient age, and sex were factors associated with severe symptoms.

CONCLUSION

A long-term symptom burden is common after oesophageal cancer surgery.

Executive functioning in psychiatric patients with deliberate self-harm, as compared with a psychiatric and a healthy comparison group

Introduction: Deliberate self-harm (DSH) is a common symptom in psychiatric disorders. It is a cross-diagnostic symptom, although it has mainly been associated with borderline personality disorder (BPD). Research has suggested an association between DSH and deficits in executive functioning. The main aim of the current study was to assess three specific aspects of executive functioning (EF) (working memory, inhibition and cognitive flexibility) among psychiatric patients with DSH, compared to a clinical and a healthy comparison group.Methods: Thirty psychiatric patients with DSH, 29 psychiatric patients without DSH and 29 healthy individuals were assessed with regard to psychiatric illness, self-harming behavior, EF, general cognitive functioning level and measures of psychopathology. The results were analyzed by means of ANOVA, regression analysis, Chi-square, and correlation analysis.Results: The patients with DSH showed deficits in cognitive flexibility and inhibition as compared to healthy individuals. In addition, the patients with DSH had greater deficits in cognitive flexibility than the patients without DSH; this effect was independent of concurrent severity of depressive symptoms but not independent of borderline symptomatology.Conclusion: Psychiatric patients with DSH may have deficits in cognitive flexibility as compared to both the healthy and clinical comparison groups. The results partly differ from previous related studies in the field. It is unclear to which extent the deficits in cognitive flexibility are due to other factors. More research is needed to understand the implications of such deficits, and if the results could be used for adapting treatment services and strategies. Future studies should include more similar comparison groups.

Mortality after surgery for primary hyperparathyroidism: results from a nationwide cohort

BACKGROUND

Contemporary patients with primary hyperparathyroidism are often diagnosed with mildly raised serum calcium levels. Previous studies have reported increased mortality in patients with primary hyperparathyroidism. This retrospective cohort study aimed to examine whether contemporary patients operated for primary hyperparathyroidism have higher mortality than the general population, and whether mortality in these patients is associated with serum calcium concentration, adenoma weight or multiglandular disease.

METHODS

Patients from a Swedish national cohort consisting of patients registered in the Scandinavian Quality Register for Thyroid, Parathyroid, and Adrenal Surgery 2003-2013, were matched with population controls. The National Patient Register, the Swedish Cause of Death Register, and socioeconomic data were cross-linked. End of follow-up was 10 years after surgery, 31 December 2015, or emigration. Mortality was analysed by standardized mortality ratio, Kaplan-Meier survival estimates, and univariable and multivariable Cox regression. Multiple imputation by chained equations was performed on missing data.

RESULTS

After exclusions, there were 5009 patients with primary hyperparathyroidism and 14 983 controls. Multivariable Cox regression analysis adjusted for age, sex, Charlson Co-morbidity Index, marital status, level of education, disposable income, and period of surgery showed lower mortality in patients than controls (hazard ratio (HR) 0.83, 95 per cent c.i. 0.75 to 0.92). In univariable Cox regression of mortality in patients, serum calcium concentration (mmoles per litre) was associated with mortality (HR 2.20, 1.53 to 3.16). This association remained in multivariable Cox regression after multiple imputation (HR 1.79, 1.19 to 2.70).

CONCLUSION

Mortality was not increased in patients operated for primary hyperparathyroidism compared with controls in a contemporary setting. Preoperative serum calcium concentration might, however, influence survival.

Single-scan ultra-selective 1D total correlation spectroscopy

Selective 1D TOCSY is a powerful tool in the assignment of NMR spectra of organic molecules. Here an order of magnitude improvement in selectivity, allowing overlapping multiplets to be excited separately, is achieved in a single scan using the very recent GEMSTONE method. The new experiment is illustrated using an antibiotic and a mixture of diastereomers.

Single-Scan Selective Excitation of Individual NMR Signals in Overlapping Multiplets

2D NMR is an immensely powerful structural tool but it is time-consuming. Targeting individual chemical groups by selective excitation in a 1D experiment can give the information required far more quickly. A major problem, however, is that proton NMR spectra are often extensively overlapped, so that in practice only a minority of sites can be selectively excited. Here we overcome that problem using a fast, single-scan method that allows selective excitation of the signals of a single proton multiplet even where it is severely overlapped by other multiplets. The advantages of the method are illustrated in a selective 1D NOESY experiment, the most efficient way to determine relative configuration unambiguously by NMR. The new approach presented here has the potential to broaden significantly the applicability of selective excitation and unlock its real potential for many other experiments.

Impact of co-morbidity on reoperation or death within 90 days of surgery for oesophageal cancer

Background

The impact of preoperative co-morbidity on postoperative outcomes in patients with oesophageal cancer is uncertain. A population-based and nationwide cohort study was conducted to assess the influence of preoperative co-morbidity on the risk of reoperation or mortality within 90 days of surgery for oesophageal cancer.

Methods

This study enrolled 98 per cent of patients who had oesophageal cancer surgery between 1987 and 2015 in Sweden. Modified Poisson regression models provided risk ratios (RRs) with 95 per cent confidence intervals (c.i.) to estimate associations between co-morbidity and risk of reoperation or death within 90 days of oesophagectomy. The RRs were adjusted for age, sex, educational level, pathological tumour stage, neoadjuvant therapy, annual hospital volume, tumour histology and calendar period of surgery.

Results

Among 2576 patients, 446 (17.3 per cent) underwent reoperation or died within 90 days of oesophagectomy. Patients with a Charlson Co-morbidity Index (CCI) score of 2 or more had an increased risk of reoperation or death compared with those with a CCI score of 0 (RR 1.78, 95 per cent c.i. 1.44 to 2.20), and the risk increased on average by 27 per cent for each point increase of the CCI (RR 1.27, 1.18 to 1.37). The RR was increased in patients with pulmonary disease (RR 1.66, 1.36 to 2.04), cardiac disease (RR 1.37, 1.08 to 1.73), diabetes (RR 1.50, 1.14 to 1.99) and cerebral disease (RR 1.40, 1.06 to 1.85).

Conclusion

Co-morbidity in general, and pulmonary disease, cardiac disease, diabetes and cerebral disease in particular, increased the risk of reoperation or death within 90 days of oesophageal cancer surgery. This highlights the value of tailored patient selection, preoperative preparation and postoperative care.

Mentorship during undergraduate surgical training: comparing perceptions of medical students and faculty at two institutions in South Africa and Sweden

ABSTRACT BACKGROUND: Having a mentor during undergraduate surgical training has been shown to positively influence medical students by increasing interest in surgery, improving confidence, and assisting in career planning. This study aimed to evaluate and compare medical student and faculty perceptions of mentorship during undergraduate surgical training and compare results between two teaching institutions in South Africa and Sweden METHODS: An electronic, online questionnaire was anonymously distributed to medical students and general surgical faculty at the University of Cape Town (UCT), South Africa, and Karolinska Institutet (KI), Stockholm, Sweden. The questionnaire consisted of multiple choice, true or false, and five-point Likert scale questions, exploring perceptions of mentorship and role models, as well as rating the most important mentor characteristics RESULTS: Approximately one third (34.2%) of students stated they had a mentor during their surgical training, with significant differences found between student cohorts (p < 0.001). The 'registrar' was most commonly reported as the best role model for medical students by faculty from both UCT (50.0%) and KI (69.4%), as well as UCT students (36.6%). Students rated the following mentor qualities significantly higher compared to faculty: student encouragement (p = 0.037), adequate supervision (p = 0.007), setting of fair expectations (p = 0.002), and teaching skills (p = 0.010 CONCLUSION: With significant differences existing in the perceptions of medical students and faculty regarding mentorship and role models during undergraduate surgical training in both South African and Swedish institutions, reconciling and harmonising these differences will be crucial in fostering constructive mentoring relationships Keywords: mentorship, role model, perception, surgical education

Impact of surgical resection rate on survival in gastric cancer: nationwide study

Background

There are marked geographical variations in the proportion of patients undergoing resection for gastric cancer. This study investigated the impact of resection rate on survival.

Methods

All patients with potentially curable gastric cancer between 2006 and 2017 were identified from the Swedish National Register of Oesophageal and Gastric Cancer. The annual resection rate was calculated for each county per year. Resection rates in all counties for all years were grouped into tertiles and classified as low, intermediate or high. Survival was analysed using the Cox proportional hazards model.

Results

A total of 3465 patients were diagnosed with potentially curable gastric cancer, and 1934 (55.8 per cent) were resected. Resection rates in the low (1261 patients), intermediate (1141) and high (1063) tertiles were 0–50.0, 50.1–62.5 and 62.6–100 per cent respectively. The multivariable Cox analysis revealed better survival for patients diagnosed in counties during years with an intermediate versus low resection rate (hazard ratio (HR) 0.81, 95 per cent c.i. 0.74 to 0.90; P < 0.001) and high versus low resection rate (HR 0.80, 0.73 to 0.88; P < 0.001).

Conclusion

This national register study showed large regional variation in resection rates for gastric cancer. A higher resection rate appeared to be beneficial with regard to overall survival for the entire population.

Effect of weight loss, exercise and risk factor control in microvascular angina. A randomized controlled pilot trial

Background

Coronary microvascular dysfunction (CMD) is a common cause of angina in women and associated with adverse cardiovascular prognosis. Currently, no evidence-based treatment for CMD exists.

Purpose

To examine whether an intervention targeting cardiovascular risk factors is feasible and improves angina symptoms and microvascular function in women with CMD and no obstructive coronary artery disease.

Methods

We randomized 62 women aged 40–75, with body mass index &gt;25 kg/m2, angina symptoms monthly or more and coronary flow velocity reserve (CFVR) &lt;2.5 to a 24-week intervention comprising low energy diet, exercise training, and optimized medical treatment of hypertension, dyslipidemia and diabetes or to usual care. Patients were assessed before randomization and after 24 weeks. The primary outcomes were CFVR assessed by transthoracic Doppler stress-echocardiography and angina burden measured by the Seattle Angina Questionnaire (SAQ). Secondary endpoints were exercise capacity (VO2max), body composition and glycemic control, anxiety and depression symptoms measured by the Hospital Anxiety and Depression Scale (HADS).

Results

Fifty-six participants (90%) completed the study. Median age was 65 years. The intervention group obtained a mean weight loss of 10 kg, mainly (9 kg) from fat tissue (all p&lt;0.0001), increased work load (p&lt;0.01), decreased triglycerides, low density lipoprotein and low plasma cholesterol (all p&lt;0.006). HbA1c in non-diabetes participants also decreased (p&lt;0.05).

There was a clinically relevant improvement in all angina symptoms (9–21-point increase on all SAQ scales (all p&lt;0.01)) as well as in depression score (p=0.008). There was no effect on CFVR or other secondary outcomes.

Conclusion

A major weight loss and intensified risk factor control resulted in significant improvement in angina burden but no improvement of coronary microvascular function among women with microvascular angina.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Unlimited research funding sources from the Capital region of Denmark and Bispebjerg-Frederiksberg Hospital internal funding sources.

Nationwide study of the impact of D2 lymphadenectomy on survival after gastric cancer surgery

Background

Gastrectomy including D2 lymphadenectomy is regarded as the standard curative treatment for advanced gastric cancer in Asia. This procedure has also been adopted gradually in the West, despite lack of support from RCTs. This study sought to investigate any advantage for long‐term survival following D2 lymphadenectomy in routine gastric cancer surgery in a Western nationwide population‐based cohort.

Methods

All patients who had a gastrectomy for cancer in Sweden in 2006–2017 were included in the study. Prospectively determined data items were retrieved from the National Register of Oesophageal and Gastric Cancer. Extent of lymphadenectomy was categorized as D1+/D2 or the less extensive D0/D1 according to the Japanese Gastric Cancer Association classification. Overall survival was analysed and, in addition, a variety of possible confounders were introduced into the Cox proportional hazards regression model.

Results

A total of 1677 patients underwent gastrectomy, of whom 471 (28·1 per cent) were classified as having a D1+/D2 and 1206 (71·9 per cent) a D0/D1 procedure. D1+/D2 lymphadenectomy was not associated with higher 30‐ or 90‐day postoperative mortality. Median overall survival for D1+/D2 lymphadenectomy was 41·5 months with a 5‐year survival rate of 43·7 per cent, compared with 38·5 months and 38·5 per cent respectively for D0/D1 (P = 0·116). After adjustment for confounders, in multivariable analysis survival was significantly higher after D1+/D2 than following D0/D1 lymphadenectomy (hazard ratio 0·81, 95 per cent c.i. 0·68 to 0·95; P = 0·012).

Conclusion

This national registry study showed that long‐term survival after gastric cancer surgery was improved after gastrectomy involving D1+/D2 lymphadenectomy compared with D0/D1 dissection.