Comparing return of bowel function after right versus extended right hemicolectomy: a retrospective analysis

BACKGROUND

Prolonged postoperative ileus (PPOI) is associated with higher morbidity and extended inpatient stay. Although evidence suggests that PPOI is more common following right-sided resections, it is uncertain if return to bowel function is similar following extended right (ERH) versus right hemicolectomy (RH).

METHODS

The recovery of patients undergoing ERH and RH in a regional hospital in New Zealand was retrospectively compared, from 2012 to 2021. Rates of PPOI, return of bowel function and postoperative complications were compared. Other factors potentially relating to PPOI were analysed.

RESULTS

293 patients were included (42 who underwent ERH, and 251 RH). PPOI was more common following ERH than RH (43% vs. 25%, P = 0.02). When accounting for the operative approach, rate of PPOI was not significantly different (42% open ERH vs. 36% open RH; P = 0.56). Excluding PPOI, return of bowel function did not differ between groups. Patient undergoing ERH versus RH had significantly higher length of stay (1 day) and Hb drop (2.5 g/L) postoperatively.

CONCLUSION

Higher rates of PPOI have been demonstrated in ERH versus RH however when controlling for approach, there was not a significant difference. Further interrogation into rates of PPOI (particularly after laparoscopic surgery) are warranted to tailor locoregional ERAS protocols.

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

BACKGROUND

Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.

METHODS

This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.

RESULTS

The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (β coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.

CONCLUSION

Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely.

Sample representativeness and influence of attrition on longitudinal data collected as part of a national medical career tracking project

BACKGROUND

The Medical Schools Outcomes Database and Longitudinal Tracking Project (MSOD) in New Zealand is one example of a national survey-based resource of medical student experiences and career outcomes. Longitudinal studies of medical students are valuable for evaluating the outcomes of medical programs against workforce objectives. As a prospective longitudinal multiple-cohort study, survey response rates at each collection point of MSOD vary. This paper assesses the effects of participant non-response rates on MSOD data.

METHODS

Demographic variables of MSOD respondents between 2012 and 2018 were compared to the distribution of the demographic variables in the population of all NZ medical graduates to ascertain whether respondent samples at multiple survey collection points were representative of the population. Analysis using logistic regression assessed the impact of participant non-response on variables at collection points throughout MSOD.

RESULTS

2874 out of a total population of 2939 domestic medical students graduating between 2012 and 2018 responded to MSOD surveys. Entry and exit surveys achieved response rates around 80% and were broadly representative of the total population on demographic variables. Post-graduation survey response rates were around 50% of the total population of graduates and underrepresented graduates from the University of Auckland. Between the entry and exit and the exit and postgraduation year three samples, there was a significant impact of non-response on ascribed variables, including age at graduation, university, gender and ethnic identity. Between the exit and postgraduation year one sample, non-response significantly impacted ascribed and non-ascribed variables, including future practice intentions.

CONCLUSION

Samples collected from MSOD at entry and exit are representative, and findings from cross-sectional studies using these datasets are likely generalisable to the wider population of NZ medical graduates. Samples collected one and three years post-graduation are less representative. Researchers should be aware of this bias when utilizing these data. When using MSOD data in a longitudinal manner, e.g. comparing the change in career intentions from one collection point to the next, researchers should appropriately control for bias due to non-response between collection points. This study highlights the value of longitudinal career-tracking studies for answering questions relevant to medical education and workforce development.

Preoperative assessment of blood supply and its role in predicting anastomotic leak

BACKGROUND

Anastomosis leak is one of the significant postoperative complications after colorectal surgery. The aim of this systematic review was to synthesize the evidence relative to the preoperative assessment of the colon and rectum blood supply and to investigate its role in predicting anastomosis leak.

METHOD

This systematic review was conducted according to the recommendations of the Cochrane Handbook for Reviews of Interventions and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. PubMed, Embase, and the Cochrane Library were searched to identify eligible studies. The main outcome variable was the preoperative assessment of patterns of blood supply to the colon and the impact of these patterns on anastomosis leak. The quality of bias control in the studies was assessed using the Newcastle-Ottawa Scale. Due to the heterogeneous nature of the included studies, no meta-analysis was conducted.

RESULTS

Fourteen studies were included. The study covered a period from 1978 to 2021. A significant degree of variation in the arterial and/or venous supply of the colon and rectum might influence anastomosis leak rates. Calcification in great blood vessels can be assessed with a preoperative computed tomography scan, which may predict anastomosis leak rates. This is supported by many experimental studies that showed increased rates of anastomosis leak after preoperative ischemia, but the extent of this impact is not well established.

CONCLUSION

Preoperative assessment of blood supply to the colon and rectum might help in planning the surgical intervention to reduce anastomosis leak rates. Calcium scoring of major arteries might predict anastomosis leak and thus play a crucial role in intraoperative decision-making.

The association of body mass index and odds of type 2 diabetes mellitus varies by race/ethnicity

OBJECTIVE

This study aimed to examine the association between body mass index (BMI; weight [kilogram]/height² [meter]) and type 2 diabetes mellitus (T2DM) among the largest three largest racial/ethnic groups in the United States.

METHODS

We compiled 10 waves of the continuous National Health and Nutrition Examination Survey from 1999-2000 through 2017-2018. Participants (N = 45,514) were those who had data on BMI, HbA_1c, and demographics. We estimated associations between BMI and prediabetes/T2DM odds for Black, Latine, and White participants.

RESULTS

BMI was associated with 10% higher odds of prediabetes/T2DM vs. having normal HbA_1c levels (odds ratio = 1.10, 95% confidence interval = 1.10-1.11) for Latine and White individuals. However, the association between BMI and prediabetes/T2DM was significantly weaker among Black individuals. When focusing on T2DM prevalence, the association with BMI for Black participants was even weaker (odds ratio = 0.97, 95% confidence interval = 0.95-0.98).

CONCLUSIONS

The unstable associations between BMI and T2DM across race indicate that BMI has received unwarranted focus as a prime predictor of T2DM. Relying on BMI introduces bias in T2DM risk estimations especially in Black individuals. Focusing on BMI places the onus on individuals to change and increases weight stigma, which can worsen health outcomes. Instead, policymakers should focus on social determinants of T2DM and its concomitant racial/ethnic disparities.

Impact of microsatellite status in early-onset colonic cancer

BACKGROUND

The molecular profile of early-onset colonic cancer is undefined. This study evaluated clinicopathological features and oncological outcomes of young patients with colonic cancer according to microsatellite status.

METHODS

Anonymized data from an international collaboration were analysed. Criteria for inclusion were patients younger than 50 years diagnosed with stage I-III colonic cancer that was surgically resected. Clinicopathological features, microsatellite status, and disease-specific outcomes were evaluated.

RESULTS

A total of 650 patients fulfilled the criteria for inclusion. Microsatellite instability (MSI) was identified in 170 (26.2 per cent), whereas 480 had microsatellite-stable (MSS) tumours (relative risk of MSI 2.5 compared with older patients). MSI was associated with a family history of colorectal cancer and lesions in the proximal colon. The proportions with pathological node-positive disease (45.9 versus 45.6 per cent; P = 1.000) and tumour budding (20.3 versus 20.5 per cent; P = 1.000) were similar in the two groups. Patients with MSI tumours were more likely to have BRAF (22.5 versus 6.9 per cent; P < 0.001) and KRAS (40.0 versus 24.2 per cent; P = 0.006) mutations, and a hereditary cancer syndrome (30.0 versus 5.0 per cent; P < 0.001; relative risk 6). Five-year disease-free survival rates in the MSI group were 95.0, 92.0, and 80.0 per cent for patients with stage I, II, and III tumours, compared with 88.0, 88.0, and 65.0 per cent in the MSS group (P = 0.753, P = 0.487, and P = 0.105 respectively).

CONCLUSION

Patients with early-onset colonic cancer have a high risk of MSI and defined genetic conditions. Those with MSI tumours have more adverse pathology (budding, KRAS/BRAF mutations, and nodal metastases) than older patients with MSI cancers.

Cost analysis of index versus delayed cholecystectomy for acute cholecystitis in a New Zealand Provincial Centre

BACKGROUND

Evidence suggests index cholecystectomy (IC) in patients with acute cholecystitis is safe, has decreased hospital stay and is cheaper than delayed cholecystectomy (DC). Costs of cholecystectomy have not previously been investigated in New Zealand. The aim of this study was to compare cost of IC with DC for patients with acute cholecystitis.

METHODS

A retrospective analysis of adults admitted to Northland hospitals with acute cholecystitis between 1 January 2015 and 31 December 2019 who underwent subsequent cholecystectomy, was performed. Actual patient-level costs were utilized for cost comparison between IC and DC. Factors associated with increased costs were assessed using multivariate analysis.

RESULTS

Two hundred and eleven patients were included in the study; 72 (34%) underwent IC and 139 (65%) DC. There was no significant difference in total cost for IC ($12 767) versus DC ($12 029) (p = 0.192); this persisted on multivariate analysis. Patients having IC had more severe cholecystitis, and 90-day representation rate following DC was 35%. Costs were increased by severity of cholecystitis, age, American Society of Anesthesiology score (ASA) and travel distance.

CONCLUSION

This study showed there is no significant difference in cost between IC and DC for patients with acute cholecystitis in Northland, New Zealand. Severity, increasing age, ASA and travel distance were drivers of costs. To recognize the cost benefits of IC, it is likely that increased rates of IC are needed.

Difficulty with Oral Health Complications in Adolescents with Developmental Disability and Obesity

INTRODUCTION

Developmental disabilities (DDs), obesity, and dental caries are highly prevalent health conditions among adolescents. Evidence indicates that a significant proportion of adolescents with DDs are obese, and those with obesity and dental caries share common risk factors.

OBJECTIVE

In this first-ever US-based cross-sectional national study, we assessed the likelihood of adolescents with DDs and obesity experiencing chronic difficulty with decayed teeth, toothaches, bleeding gums, and eating and swallowing due to a health condition among adolescents with DDs and obesity compared to adolescents with no DDs or obesity.

METHODS

For this secondary data analysis study, we used data of 68,942 adolescents aged 10 to 17 y from the 2016 through 2019 National Survey of Children's Health. Weighted descriptive and bivariate analyses were conducted. Four multiple logistic regression models predicting chronic difficulty in the past 12 mo with decayed teeth, toothaches, bleeding gums, and eating and swallowing due to a health condition were conducted, controlling for other variables.

RESULTS

The adjusted odds ratio (aOR) of experiencing chronic difficulty in the past 12 mo for adolescents with no DDs or obesity was significantly lower for decayed teeth (aOR, 0.64; 95% confidence interval [CI], 0.51-0.80; P < 0.0001), toothaches (aOR, 0.43; 95% CI, 0.30-0.60; P < 0.0001), bleeding gums (aOR, 0.48; 95% CI, 0.33-0.70; P < 0.0001), and eating or swallowing due to a health condition (aOR, 0.34; 95% CI, 0.20-0.57; P < 0.0001) compared to adolescents with both DDs and obesity.

CONCLUSIONS

Results from this study indicate that DD adolescents with obesity have more/greater impending oral health needs than adolescents with no DDs or obesity.

KNOWLEDGE TRANSFER STATEMENT

Results of this study highlight the high oral health needs and the chronic difficulty adolescents with developmental disabilities and obesity experience compared to adolescents without developmental disabilities and obesity. Targeted oral health policies and interventions that will promote oral health among this high-risk group are recommended.

Microsatellite instability in young patients with rectal cancer: molecular findings and treatment response

In this study of 400 patients with early-onset rectal cancer, 12.5 per cent demonstrated microsatellite instability (MSI). MSI was associated with a reduced likelihood of nodal positivity, an increased rate of pathological complete response, and improved disease-specific survival.

Hyponatremia an indicator of complicated appendicitis in children: Starship experience

BACKGROUND

Timely preoperative recognition of children with complicated appendicitis allows for planning and effective management. The aim of this study was to evaluate hyponatremia, an objective biochemical marker, as a predictor of complicated appendicitis.

METHODS

A retrospective review of 1283 paediatric patients (≤15 years) who underwent acute appendicectomy from January 2016 to December 2020 (5-year period) was performed. Complicated appendicitis was defined by intraoperative findings of; macroscopic perforation, free pus, gangrene, faecal contamination or intraabdominal abscess. Comparison groups consisted of patients with complicated appendicitis, patients with uncomplicated appendicitis and patients with presumed appendicitis who went on to have no appendicitis on histology (no appendicitis group). Preoperative hyponatremia was defined as serum sodium <135 mmol/L.

RESULTS

Of the 1283 children; 35% (443/1283) had complicated appendicitis, 54% (690/1283) had uncomplicated appendicitis and 12% (150/1283) had no appendicitis. Rates of hyponatremia were much greater in the complicated group (31.4%; 139/443) than in the uncomplicated group (3.8%; 26/690) (p < 0.0001) or the no appendicitis group 10.7% (16/150) (p < 0.0001). The no appendicitis group had higher rates of hyponatremia than the uncomplicated group (p = 0.001), an unexpected finding. The receiver operating characteristic curve for diagnosis of complicated appendicitis versus uncomplicated appendicitis, using a cut-off serum sodium of <135 mmol/L will identify complicated appendicitis with sensitivity 31.4% and specificity of 95.7% (area under the curve of 0.76).

CONCLUSION

Hyponatremia is a discriminating predictor of complicated appendicitis in a paediatric population.

P-P02 Incidence and risk factors for chyle leak after pancreatic surgery: a systematic review and meta-analysis

Background

The incidence of, and risk factors for chyle leak, as defined by the 2017 International Study Group on Pancreatic Surgery (ISGPS), remain unknown. 

Methods

MEDLINE, EMBASE, and Scopus were systematically searched for studies of patients undergoing pancreatectomy that reported chyle leak according to the 2017 ISGPS definition. The primary outcomes were the incidence of overall and clinically-relevant chyle leak. A random-effects pairwise meta-analysis was used to identify risk factors where possible. 

Results

Thirty-five studies including 7083 patients were included in the meta-analysis. The weighted incidence of overall chyle leak was 6.8% (95% CI 5.6 - 8.2) and clinically-relevant chyle leak was 5.5% (95% CI 3.8 - 7.7). Pancreaticoduodenectomy, total pancreatectomy and distal pancreatectomy were associated with a CL incidence of 7.3%, 4.3%, 5.8% respectively. Fourteen individual risk factors for chyle leak were identified from included studies. Younger age, low prognostic nutritional index, para-aortic node manipulation, lymphatic involvement, and post-pancreatectomy pancreatitis were significantly associated with chyle leak, all from individual studies.

Conclusions

The incidence of overall chyle leak and clinically relevant chyle leak after pancreatic surgery, as defined by the 2017 ISGPS definition is 6.8% and 5.5% respectively. Several risk factors for chyle leak were identified in the present review, however, larger high-quality studies are needed to more accurately define these risks.

Characteristics of Early-Onset vs Late-Onset Colorectal Cancer: A Review

Importance

The incidence of early-onset colorectal cancer (younger than 50 years) is rising globally, the reasons for which are unclear. It appears to represent a unique disease process with different clinical, pathological, and molecular characteristics compared with late-onset colorectal cancer. Data on oncological outcomes are limited, and sensitivity to conventional neoadjuvant and adjuvant therapy regimens appear to be unknown. The purpose of this review is to summarize the available literature on early-onset colorectal cancer.

Observations

Within the next decade, it is estimated that 1 in 10 colon cancers and 1 in 4 rectal cancers will be diagnosed in adults younger than 50 years. Potential risk factors include a Westernized diet, obesity, antibiotic usage, and alterations in the gut microbiome. Although genetic predisposition plays a role, most cases are sporadic. The full spectrum of germline and somatic sequence variations implicated remains unknown. Younger patients typically present with descending colonic or rectal cancer, advanced disease stage, and unfavorable histopathological features. Despite being more likely to receive neoadjuvant and adjuvant therapy, patients with early-onset disease demonstrate comparable oncological outcomes with their older counterparts.

Conclusions and Relevance

The clinicopathological features, underlying molecular profiles, and drivers of early-onset colorectal cancer differ from those of late-onset disease. Standardized, age-specific preventive, screening, diagnostic, and therapeutic strategies are required to optimize outcomes.

The role of amyloid oligomers in neurodegenerative pathologies

Many neurodegenerative diseases are rooted in the activities of amyloid-like proteins which possess conformations that spread to healthy proteins. These include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). While their clinical manifestations vary, their protein-level mechanisms are remarkably similar. Aberrant monomeric proteins undergo conformational shifts, facilitating aggregation and formation of solid fibrils. However, there is growing evidence that intermediate oligomeric stages are key drivers of neuronal toxicity. Analysis of protein dynamics is complicated by the fact that nucleation and growth of amyloid-like proteins is not a linear pathway. Feedback within this pathway results in exponential acceleration of aggregation, but activities exerted by oligomers and fibrils can alter cellular interactions and the cellular environment as a whole. The resulting cascade of effects likely contributes to the late onset and accelerating progression of amyloid-like protein disorders and the widespread effects they have on the body. In this review we explore the amyloid-like proteins associated with AD, PD, HD and ALS, as well as the common mechanisms of amyloid-like protein nucleation and aggregation. From this, we identify core elements of pathological progression which have been targeted for therapies, and which may become future therapeutic targets.

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

BACKGROUND

80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality.

METHODS

This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494.

FINDINGS

Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70-8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39-8·80) and upper-middle-income countries (2·06, 1·11-3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26-11·59) and upper-middle-income countries (3·89, 2·08-7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications.

INTERPRETATION

Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications.

FUNDING

National Institute for Health Research Global Health Research Unit.

Epidural Versus Transabdominal Wall Catheters: A Comparative Study of Outcomes After Pancreatic Resection

BACKGROUND

This study compared epidural analgesia with local anesthetic administration via transabdominal wall catheters (TAWC), to determine the effect on perioperative outcomes in pancreatic surgery.

MATERIALS AND METHODS

A retrospective review of patients undergoing open pancreatic surgery at Auckland City Hospital from 2015 to 2018 was undertaken. Data collected included patient demographics, type of perioperative analgesia, intravenous fluid and vasopressor use, length of high dependency unit stay, postoperative complications, and length of hospital stay.

RESULTS

Seventy-two patients underwent pancreatic surgery, of which 47 had epidural analgesia and 25 TAWC. The median age was 64 y (range 29-85). Failure of analgesia method occurred in 45% of epidural patients and 28% of TAWC patients (P = 0.209). There was no significant difference in volume of intravenous fluid given or need for vasopressors in the first 3 postoperative days, length of high dependency unit stay (median 1 d, P = 0.2836), rates of postoperative pancreatic fistula (32% versus 40%, P = 0.6046), postoperative complications (38% versus 20%, P = 0.183), or mortality (0.04% versus 0.04%, P = 1.0).

CONCLUSIONS

Epidural analgesia and TAWC may have comparable perioperative outcomes in patients undergoing pancreatic surgery. Further randomized studies with a larger cohort of patients are warranted to identify the best postoperative analgesic method in patients undergoing pancreatic resection.

0747 Study Design of an Open-Label Extension and Switch Study for Once Nightly Sodium Oxybate, FT218, in NT1 and NT2 Patients

Introduction

Avadel Pharmaceuticals has developed FT218, a once nightly sodium oxybate (SO) formulation for the treatment of excessive daytime sleepiness (EDS) and cataplexy in narcoleptic patients. REST-ON, a pivotal efficacy/safety study is expected to be completed in the first half of 2020. Previous Phase 1 studies have demonstrated FT218 delivers a pharmacokinetic profile needed for once-nightly dosing. The purpose of this study is to evaluate long-term safety of FT218 in REST-ON completers and dosing strategy when switching from twice-nightly SO to FT218.

Methods

The study will enroll NT1/NT2 patients who completed REST-ON or patients switching from stable dose of twice-nightly SO to FT218. REST-ON completers will initiate FT218 at 4.5 g and increase by 1.5 g to the highest tolerated dose or the dose deemed effective (up to 9 g). Switch patients will initiate FT218 at the equivalent/closest dose to their current twice-nightly SO and titrate in accord with safety/efficacy. The study will enroll approximately 250 patients for a duration of two years.

Results

The primary endpoint for REST-ON completers will be safety and tolerability. Secondary endpoints for REST-ON completers will include changes in ESS, reported cataplexy and other REM associated phenomena as well as changes in clinician and patient global impression. For switch patients, endpoints will include percentage of subjects that stay on the same, higher or lower dose of FT218 compared to twice-nightly SO, as well as the percentage of subjects who report a preference for the once-nightly dosing regimen.

Conclusion

The results of this open label extension/switch study will further elucidate the potential benefits of once-nightly FT218 regarding long term safety/tolerability, nocturnal safety/tolerability and efficacy, and importantly provide dosing and preference data for patients switching from twice-nightly SO to once-nightly FT218.

Support

This work was supported by Avadel Pharmaceuticals.

Network meta-analysis comparing techniques and outcomes of stump closure after distal pancreatectomy

Background

The incidence of postoperative pancreatic fistula (POPF) after distal pancreatectomy remains high, and different pancreatic stump closure techniques have been used to reduce the incidence. A network meta-analysis was undertaken to compare the most frequently performed pancreatic stump closure techniques after distal pancreatectomy and determine the technique associated with the lowest POPF rate.

Methods

A systematic search of the Scopus, PubMed, MEDLINE and Embase databases was conducted to identify eligible RCTs. The primary outcome was the occurrence of clinically relevant POPF. Secondary outcomes were duration of operation, blood loss, intrabdominal collections, postoperative complications and 30-day mortality.

Results

Sixteen RCTs including 1984 patients and eight different pancreatic stump closure techniques were included in the network meta-analysis. Patch coverage of the pancreatic stump (round ligament or seromuscular patch) after stapler or suture closure ranked best, with the lowest rates of clinically relevant POPF, lowest volume of intraoperative blood loss, fewer intra-abdominal abscesses, and lower rates of overall complications and 30-day mortality. Round ligament patch closure outperformed seromuscular patch closure in preventing clinically relevant POPF with a significantly larger cohort for comparative analysis. Pancreaticoenteric anastomotic closure consistently ranked poorly for most reported postoperative outcomes.

Conclusion

Patch coverage after stapler or suture closure has the lowest POPF rate and best outcomes among stump closure techniques after distal pancreatectomy.

Prionoid Proteins in the Pathogenesis of Neurodegenerative Diseases

There is a growing body of evidence that prionoid protein behaviors are a core element of neurodegenerative diseases (NDs) that afflict humans. Common elements in pathogenesis, pathological effects and protein-level behaviors exist between Alzheimer's Disease (AD), Parkinson's Disease (PD), Huntington's Disease (HD) and Amyotrophic Lateral Sclerosis (ALS). These extend beyond the affected neurons to glial cells and processes. This results in a complicated system of disease progression, which often takes advantage of protective processes to promote the propagation of pathological protein aggregates. This review article provides a current snapshot of knowledge on these proteins and their intrinsic role in the pathogenesis and disease progression seen across NDs.

Estimating kangaroo density by aerial survey: a comparison of thermal cameras with human observers

Abstract ContextAerial surveys provide valuable information about the population status and distribution of many native and pest vertebrate species. They are vital for evidence-based monitoring, budget planning and setting management targets. Despite aircraft running costs, they remain one of the most cost-effective ways to capture distribution and abundance data over a broad area. In Australia, annual surveys of large macropods are undertaken in several states to inform management, and in some jurisdictions, to help set commercial kangaroo harvest quotas. Improvements in the cost efficiencies of these surveys are continually sought. Aerial thermal imaging techniques are increasingly being tested for wildlife surveys, but to date no studies have directly compared population data derived from thermal imaging with data collected by human observers during the same flight. AimsDuring an aerial survey of western grey kangaroos (Macropus fuliginosus), eastern grey kangaroos (M. giganteus) and red kangaroos (Osphranter rufus) across the state of Victoria, Australia, the objective was to conduct a direct comparison of the effectiveness of thermal camera technology and human observers for estimating kangaroo populations from aerial surveys. MethodsA thermal camera was mounted alongside an aerial observer on one side of the aircraft for a total of 1360km of transect lines. All thermal footage was reviewed manually. Population density estimates and distance sampling models were compared with human observer counts. Key resultsOverall, the kangaroo density estimates obtained from the thermal camera data were around 30% higher than estimates derived from aerial observer counts. This difference was greater in wooded habitats. Conversely, human-derived counts were greater in open habitats, possibly due to interference from sunlight and flushing. It was not possible to distinguish between species of macropod in the thermal imagery. ConclusionsThermal survey techniques require refining, but the results of the present study suggest that with careful selection of time of day for surveys, more accurate population estimates may be possible than with conventional aerial surveys. ImplicationsConventional aerial surveys may be underestimating animal populations in some habitats. Further studies that directly compare the performance of aerial observers and thermal imaging are required across a range of species and habitats.

Review of Russian language studies on radionuclide behaviour in agricultural animals: Transfer to animal tissues

Data on radionuclide transfer to animals from research performed in the former Soviet Union were reviewed to collate transfer coefficient values (F_f) to animal tissues such as liver, kidney and bone, but not muscle which has previously been reported. The derived values were compared with selected data published in the English language literature. The new data are mainly for ⁹⁰Sr and ¹³⁷Cs, although some data were also provided for ³H, ⁵⁴Mn, ⁵⁹Fe, ⁶⁰Co, ²²Na ⁶⁵Zn, ¹³¹I and U. The Russian language data may provide a basis for better informed evaluation of radiation dose from the consumption of such animal products, which can form important components of the diet in some countries.

A Phase II Study of Pembrolizumab in EGFR-Mutant, PD-L1+, Tyrosine Kinase Inhibitor Naïve Patients With Advanced NSCLC

BACKGROUND

Despite the significant antitumor activity of pembrolizumab in NSCLC, clinical benefit has been less frequently observed in patients whose tumors harbor EGFR mutations compared to EGFR wild-type patients. Our single-center experience on the KEYNOTE-001 trial suggested that pembrolizumab-treated EGFR-mutant patients, who were tyrosine kinase inhibitor (TKI) naïve, had superior clinical outcomes to those previously treated with a TKI. As TKI naïve EGFR-mutants have generally been excluded from pembrolizumab studies, data to guide treatment decisions in this patient population is lacking, particularly in patients with programmed death ligand 1 (PD-L1) expression ≥50%.

METHODS

We conducted a phase II trial (NCT02879994) of pembrolizumab in TKI naive patients with EGFR mutation-positive, advanced NSCLC and PD-L1-positive (≥1%, 22C3 antibody) tumors. Pembrolizumab was administered 200 mg every 3 weeks. The primary endpoint was objective response rate. Secondary endpoints included safety of pembrolizumab, additional pembrolizumab efficacy endpoints, and efficacy and safety of an EGFR TKI after pembrolizumab.

RESULTS

Enrollment was ceased due to lack of efficacy after 11 of 25 planned patients were treated. Eighty-two percent of trial patients were treatment naïve, 64% had sensitizing EGFR mutations, and 73% had PD-L1 expression ≥50%. Only 1 patient had an objective response (9%), but repeat analysis of this patient's tumor definitively showed the original report of an EGFR mutation to be erroneous. Observed treatment-related adverse events were similar to prior experience with pembrolizumab, but two deaths within 6 months of enrollment, including one attributed to pneumonitis, were of concern.

CONCLUSIONS

Pembrolizumab's lack of efficacy in TKI naïve, PD-L1+, EGFR-mutant patients with advanced NSCLC, including those with PD-L1 expression ≥50%, suggests that it is not an appropriate therapeutic choice in this setting.

Abstract P5-05-05: Patient-derived triple negative breast cancer xenografts as a translational model to screen for novel kinase pathways

Overall, triple negative breast cancers (TNBCs) constitute 12% of all breast cancers, and is approximately twice more prevalent in African-American populations. Louisiana has a high proportion of African-American residents (32.5% in 2015), and thus hosts a higher population of TNBC patients. TNBCs have an aggressive phenotype that is elusive to the targeted therapeutics used to treat other breast cancer subtypes. Certain kinase families have been extensively studied as regulators of epithelial-mesenchymal transition (EMT), a process involved in the initiation of cancer metastasis. Discovery of novel kinase targets within the subset of uncharacterized kinases could provide important insight into future targeted therapies. However, current models utilized in target discovery research are limited by the inability to accurately recapitulate the complex stromal architecture and heterogenous genetic and molecular composition of breast cancer. Furthermore, immortalized cell lines are limited to a 2D environment and over time acquire mutations that may not reflect the primary tumor. Recently, our laboratory has successfully established two TNBC patient-derived xenograft (PDX) models derived from African-American patients, and generated cell lines (TU-BCx-2K1, TU-BCx-2O0) and mammospheres. One of these models, 2O0, presents tumor architecture, cellular composition, genomic (qRT-PCR) and protein (western blot) expressions that are concordant with a claudin-low subtype, which has higher rates of metastasis and recurrence. Furthermore, we show that both TNBC models metastasize to the lungs, and exhibit molecular characteristics consistent with mesenchymal phenotypes. We utilized these translational PDX models to screen a library of small molecule inhibitors that represent a variety of kinase pathways to identify novel therapeutic targets and/or pathways that are specific to TNBC subtypes. We found in a preliminary cell morphology screen using three TNBC cell lines (MDA-MB-231, BT549, MDA-MB-157), two small molecule inhibitors that increased epithelial marker (CDH1) gene expression, suppressed mesenchymal (VIM, c-FOS, SNAI1, ZEB1) expression and/or suppressed cellular motility in transwell migration assays. We observed after ex vivo treatments with our PDX tumors the two compounds increase the epithelial marker CDH1 expression, and suppress mesenchymal markers (VIM, MMP2, c-FOS, SNAI1, ZEB1) expressions. We confirm these findings in the TU-BCx-2K1 cell line. Kinase array data revealed candidate kinases responsible for the observed EMT changes in the two compounds of interest (NEK5, NEK9, NEK1 potentially affect cell motility; SRC-family kinases, TAOK2, STK10 potentially affect EMT gene changes); we plan to utilize the PDX cell lines to characterize these kinases in EMT. We aim to ultimately discover novel therapeutic targets specific to different TNBC molecular subtypes.

Citation Format: Matossian M, Burks H, Bowles A, Sabol R, Hoang V, Elliott S, Bunnell B, Zuercher W, Drewry D, Wells C, Alfortish A, Lee S, Hartono A, Jones S, Moroz K, Zea A, Burow M, Collins-Burow B. Patient-derived triple negative breast cancer xenografts as a translational model to screen for novel kinase pathways [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-05-05.

Assessment and manifestation of central sensitisation across different chronic pain conditions

Different neuroplastic processes can occur along the nociceptive pathways and may be important in the transition from acute to chronic pain and for diagnosis and development of optimal management strategies. The neuroplastic processes may result in gain (sensitisation) or loss (desensitisation) of function in relation to the incoming nociceptive signals. Such processes play important roles in chronic pain, and although the clinical manifestations differ across condition processes, they share some common mechanistic features. The fundamental understanding and quantitative assessment of particularly some of the central sensitisation mechanisms can be translated from preclinical studies into the clinic. The clinical perspectives are implementation of such novel information into diagnostics, mechanistic phenotyping, prevention, personalised treatment, and drug development. The aims of this paper are to introduce and discuss (1) some common fundamental central pain mechanisms, (2) how they may translate into the clinical signs and symptoms across different chronic pain conditions, (3) how to evaluate gain and loss of function using quantitative pain assessment tools, and (4) the implications for optimising prevention and management of pain. The chronic pain conditions selected for the paper are neuropathic pain in general, musculoskeletal pain (chronic low back pain and osteoarthritic pain in particular), and visceral pain (irritable bowel syndrome in particular). The translational mechanisms addressed are local and widespread sensitisation, central summation, and descending pain modulation.

Significance

Central sensitisation is an important manifestation involved in many different chronic pain conditions. Central sensitisation can be different to assess and evaluate as the manifestations vary from pain condition to pain condition. Understanding central sensitisation may promote better profiling and diagnosis of pain patients and development of new regimes for mechanism based therapy. Some of the mechanisms underlying central sensitisation can be translated from animals to humans providing new options in development of therapies and profiling drugs under development.

Availability and approval of cannabis-based medicines for chronic pain management and palliative/supportive care in Europe: A survey of the status in the chapters of the European Pain Federation

BACKGROUND

There is considerable public and political interest in the use of cannabis products for medical purposes.

METHODS

The task force of the European Pain Federation (EFIC) conducted a survey with its national chapters representatives on the status of approval of all types of cannabis-based medicines, the covering of costs and the availability of a position paper of a national medical association on the use of medical cannabis for chronic pain and for symptom control in palliative/supportive care.

RESULTS

Thirty-one out of 37 contacted councillors responded. Plant-derived tetrahydrocannabinol/cannabidiol (THC/CBD) oromucosal spray is approved for spasticity in multiple sclerosis refractory to conventional treatment in 21 EFIC chapters. Plant-derived THC (dronabinol) is approved for some palliative care conditions in four EFIC chapters. Synthetic THC analogue (nabilone) is approved for chemotherapy-associated nausea and vomiting refractory to conventional treatment in four EFIC chapters'. Eight EFIC chapters' countries have an exceptional and six chapters an expanded access programme for medical cannabis. German and Israeli pain societies recommend the use of cannabis-based medicines as third-line drug therapies for chronic pain within a multicomponent approach. Conversely, the German medical association and a team of finish experts and officials do not recommend the prescription of medical cannabis due to the lack of high-quality evidence of efficacy and the potential harms.

CONCLUSIONS

There are marked differences between the countries represented in EFIC in the approval and availability of cannabis-based products for medical use. EFIC countries are encouraged to collaborate with the European Medicines Agency to publish a common document on cannabis-based medicines.

SIGNIFICANCE

There are striking differences between European countries in the availability of plant-derived and synthetic cannabinoids and of medical cannabis for pain management and for symptom control in palliative care and in the covering of costs by health insurance companies or state social security systems.

Defining low anterior resection syndrome: a systematic review of the literature

AIM

There is increasing awareness of the poor functional outcome suffered by many patients after sphincter-preserving rectal resection, termed 'low anterior resection syndrome' (LARS). There is no consensus definition of LARS and varying instruments have been employed to measure functional outcome, complicating research into prevalence, contributing factors and potential therapies. We therefore aimed to describe the instruments and outcome measures used in studies of bowel dysfunction after low anterior resection and identify major themes used in the assessment of LARS.

METHOD

A systematic review of the literature was performed for studies published between 1986 and 2016. The instruments and outcome measures used to report bowel function after low anterior resection were extracted and their frequency of use calculated.

RESULTS

The search revealed 128 eligible studies. These employed 18 instruments, over 30 symptoms, and follow-up time periods from 4 weeks to 14.6 years. The most frequent follow-up period was 12 months (48%). The most frequently reported outcomes were incontinence (97%), stool frequency (80%), urgency (67%), evacuatory dysfunction (47%), gas-stool discrimination (34%) and a measure of quality of life (80%). Faecal incontinence scoring systems were used frequently. The LARS score and the Bowel Function Instrument (BFI) were used in only nine studies.

CONCLUSION

LARS is common, but there is substantial variation in the reporting of functional outcomes after low anterior resection. Most studies have focused on incontinence, omitting other symptoms that correlate with patients' quality of life. To improve and standardize research into LARS, a consensus definition should be developed, and these findings should inform this goal.

Improving the quantity, quality and transparency of data used to derive radionuclide transfer parameters for animal products. 2. Cow milk

Under the International Atomic Energy Agency (IAEA) MODARIA (Modelling and Data for Radiological Impact Assessments) Programme, there has been an initiative to improve the derivation, provenance and transparency of transfer parameter values for radionuclides from feed to animal products that are for human consumption. A description of the revised MODARIA 2016 cow milk dataset is described in this paper. As previously reported for the MODARIA goat milk dataset, quality control has led to the discounting of some references used in IAEA's Technical Report Series (TRS) report 472 (IAEA, 2010). The number of Concentration Ratio (CR) values has been considerably increased by (i) the inclusion of more literature from agricultural studies which particularly enhanced the stable isotope data of both CR and F_m and (ii) by estimating dry matter intake from assumed liveweight. In TRS 472, the data for cow milk were 714 transfer coefficient (F_m) values and 254 CR values describing 31 elements and 26 elements respectively. In the MODARIA 2016 cow milk dataset, F_m and CR values are now reported for 43 elements based upon 825 data values for F_m and 824 for CR. The MODARIA 2016 cow milk dataset F_m values are within an order of magnitude of those reported in TRS 472. Slightly bigger changes are seen in the CR values, but the increase in size of the dataset creates greater confidence in them. Data gaps that still remain are identified for elements with isotopes relevant to radiation protection.

Drug-resistant tuberculosis clinical trials: proposed core research definitions in adults

Drug-resistant tuberculosis (DR-TB) is a growing public health problem, and for the first time in decades, new drugs for the treatment of this disease have been developed. These new drugs have prompted strengthened efforts in DR-TB clinical trials research, and there are now multiple ongoing and planned DR-TB clinical trials. To facilitate comparability and maximise policy impact, a common set of core research definitions is needed, and this paper presents a core set of efficacy and safety definitions as well as other important considerations in DR-TB clinical trials work. To elaborate these definitions, a search of clinical trials registries, published manuscripts and conference proceedings was undertaken to identify groups conducting trials of new regimens for the treatment of DR-TB. Individuals from these groups developed the core set of definitions presented here. Further work is needed to validate and assess the utility of these definitions but they represent an important first step to ensure there is comparability in clinical trials on multidrug-resistant TB.

Improving the quantity, quality and transparency of data used to derive radionuclide transfer parameters for animal products. 1. Goat milk

Under the MODARIA (Modelling and Data for Radiological Impact Assessments Programme of the International Atomic Energy Agency), there has been an initiative to improve the derivation, provenance and transparency of transfer parameter values for radionuclides. The approach taken for animal products is outlined here and the first revised table for goat milk is provided. Data from some references used in TRS 472 were removed and reasons given for removal. Particular efforts were made to improve the number of CR (concentration ratio) values which have some advantages over transfer coefficients. There is little difference in most of the new CR and Fm (transfer coefficient) values for goat milk compared with those in TRS 472. In TRS 472, 21 CR values were reported for goat milk. In the 2015 dataset for goat milk CR values for a further 14 elements are now included. The CR and Fm values for only one element (Co) were removed.

Radionuclide biological half-life values for terrestrial and aquatic wildlife

The equilibrium concentration ratio is typically the parameter used to estimate organism activity concentrations within wildlife dose assessment tools. Whilst this is assumed to be fit for purpose, there are scenarios such as accidental or irregular, fluctuating, releases from licensed facilities when this might not be the case. In such circumstances, the concentration ratio approach may under- or over-estimate radiation exposure depending upon the time since the release. To carrying out assessments for such releases, a dynamic approach is needed. The simplest and most practical option is representing the uptake and turnover processes by first-order kinetics, for which organism- and element-specific biological half-life data are required. In this paper we describe the development of a freely available international database of radionuclide biological half-life values. The database includes 1907 entries for terrestrial, freshwater, riparian and marine organisms. Biological half-life values are reported for 52 elements across a range of wildlife groups (marine = 9, freshwater = 10, terrestrial = 7 and riparian = 3 groups). Potential applications and limitations of the database are discussed.