Mid-treatment Fluorodeoxyglucose Positron Emission Tomography in Human Papillomavirus-related Oropharyngeal Squamous Cell Carcinoma Treated with Primary Radiotherapy: Nodal Metabolic Response Rate can Predict Treatment Outcomes

AIMS

To evaluate whether biomarkers derived from fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) performed prior to (prePET) and during the third week (interim PET; iPET) of radiotherapy can predict treatment outcomes in human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPC).

MATERIALS AND METHODS

This retrospective analysis included 46 patients with newly diagnosed OPC treated with definitive (chemo)radiation and all patients had confirmed positive HPV status (HPV+OPC) based on p16 immunohistochemistry. The maximum standardised uptake value (SUV_max), metabolic tumour volume (MTV) and total lesional glycolysis (TLG) of primary, index node (node with the highest TLG) and total lymph nodes and their median percentage (≥50%) reductions in iPET were analysed, and correlated with 5-year Kaplan-Meier and multivariable analyses (smoking, T4, N2b-3 and AJCC stage IV), including local failure-free survival, regional failure-free survival, locoregional failure-free survival (LRFFS), distant metastatic failure-free survival (DMFFS), disease-free survival (DFS) and overall survival.

RESULTS

There was no association of outcomes with prePET parameters observed on multivariate analysis. A complete metabolic response of primary tumour was seen in 13 patients; the negative predictive value for local failure was 100%. More than a 50% reduction in total nodal MTV provided the best predictor of outcomes, including LRFFS (88% versus 47.1%, P = 0.006, hazard ratio = 0.153) and DFS (78.2% versus 41.2%, P = 0.01, hazard ratio = 0.234). More than a 50% reduction in index node TLG was inversely related to DMFFS: a better nodal response was associated with a higher incidence of distant metastatic failure (66.7% versus 100%, P = 0.009, hazard ratio = 3.0).

CONCLUSION

The reduction (≥50%) of volumetric nodal metabolic burden can potentially identify a subgroup of HPV+OPC patients at low risk of locoregional failure but inversely at higher risk of distant metastatic failure and may have a role in individualised adaptive radiotherapy and systemic therapy.

Anatomical study of the anterior interosseous nerv

BACKGROUND

The aim of this study is to investigate the location of nerves that innervate the flexor digitorum profundus (FDP), the flexor pollicis longus (FPL) and the pronator quadratus muscles. It also investigates the change in nerve location with hand movement.

MATERIALS AND METHODS

We studied 30 adult cadavers (17 males and 13 females) with a mean age of 69.5 years (range, 60-95 years). The reference line was from the humeral epicondylar line to the styloid process line of both the radius and ulnar bones. This study measured the anterior interosseous nerve (AIN) branch outpoint and the innervated muscle nerve entry point to the muscle belly. It also examines nerve position changes as related to making a fist.

RESULTS

The reference line mean distance was 24.1 ± 1.2 cm. The median branched into the AIN at 18.0 ± 4.0%. We found the most densely distributed section of the nerves' entry point to the muscle belly to be at a distance of 30% to 40% for the FDP and from 30% to 40% for the FPL. Except for the FPL, the nerve branch outpoints and the FDP moved 3.0%, depending upon hand movements.

CONCLUSIONS

The results of this study show that it will be necessary to consider the anatomy of the nerve location as it enters the muscle belly as well as how it changes with movement.

POS1448 EVIDENCE BASED PRACTICE: WHAT IS THE EVIDENCE THAT BRITISH SOCIETY FOR RHEUMATOLOGY GUIDELINES ARE EVIDENCE BASED?

Background:

Clinical practice guidelines are designed to ensure that patients are treated according to best evidence, with the goal of optimizing clinical outcomes and reducing unwarranted variation in care. They compile, rate and translate the data available into recommendations that form the basis of evidence-based practice for most clinicians. Despite their importance, the evidence base informing different guidelines varies in quality. A recent study of American College of Rheumatology (ACR) Practice Guidelines demonstrated only 17 of 35 class I (strong benefit to harm ratio) recommendations were supported by level A evidence (high quality randomized controlled trails or meta-analyses)1.

Objectives:

To review the evidence supporting the British Society for Rheumatology (BSR) guidelines.

Methods:

Thirteen sets of guidelines that were available on the BSR website as of October 16th 2019 were reviewed (https://www.rheumatology.org.uk/practice-quality/guidelines). A range of methodologies (including Grading of Recommendations Assessment, Development and Evaluation (GRADE), Scottish Intercollegiate Guidelines Network (SIGN), EULAR and Royal College of Physicians (RCP) recommendations) were used to assess the quality of evidence and strength of recommendation. For comparability between guidelines the level of evidence was converted to a score between I (highest quality) and IV (lowest quality) and the strength of recommendation was converted to a rating between A and D. The polymyalgia rheumatica guideline was not assessed due to unclear methodology and lack of level of evidence for all recommendations.

Results:

Of the 12 BSR guidelines assessed, there were 554 recommendations in total. The number of recommendations per guideline ranged between 13 and 80. Across all assessed guidelines, 94 recommendations (17.0%) were classified as level I, 161 (29.1%) as level 2 and 299 (54.0%) as level 3 or 4. These figures are similar to those reported in the ACR guidelines (23%, 19% and 58% respectively)1. The proportion of level I evidence varied from 46.2% (Axial Spondyloarthropathy guideline) to 0% (Hot Swollen Joint guideline).

Conclusion:

Over half of all BSR guideline recommendations have level of supporting evidence of III/IV. A wide range of methodologies are used to generate BSR guidelines (GRADE, SIGN, RCP / EULAR). This makes it challenging for readers unfamiliar with these approaches to interpret evidence and hinders comparisons between guidelines. A standardized methodology for future guideline development would overcome these barriers.

References:

[1]Duarte-Garcia A, Zamore R & Wong JB. The Evidence Basis for the American College of Rheumatology Practice Guidelines. JAMA Intern Med, 2018 Jan 1;178(1):146-148.

Disclosure of Interests:

None declared

Clinical and electrophysiological characteristics of extra-pulmonary vein triggers in patients who underwent catheter ablation for atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Background

Extra-pulmonary vein (PV) triggers play significant roles in atrial fibrillation (AF) recurrence after AF catheter ablation (AFCA).

Purpose

We explore the clinical and electrophysiological characteristics of extra-PV triggers in de novo and repeat-AFCA procedure.

Methods

We included 2,151 patients who had de novo AFCA and 319 repeat AFCA (female 28.0%, 59.1 ± 10.8 years old, paroxysmal AF 65.1%) those underwent post-procedural isoproterenol (ISO) provocation tests. We analysed the clinical, electrophysiological, and procedure-related factors associated with extra-PV triggers.

Results

Extra-PV triggers were documented in 11.9% (1.19 ± 0.42 foci) after de novo-AFCA and 27.0% (1.37 ± 0.65 foci) after repeat-AFCA (p = 0.004). LA volume index (OR 1.02 [1.01-1.03], p = 0.004), history of vascular disease (OR 0.55[0.31-0.91], p = 0.028) and Lead I amplitude of electrocardiogram (OR <0.01 [<0.01-0.62], p = 0.032) were independently associated with the existence of extra-PV triggers in de-novo procedure. Women (OR 1.84 [1.03-3.25], p = 0.037) and LA appendage volume (OR 1.04 [1.01-1.07] p = 0.027) were independently associated with extra-PV triggers during the redo-mapping procedure. Septum (28.4%), coronary sinus (24.0%), and superior vena cava (19.6%) were common extra-PV foci, and septal foci were more commonly found in repeat mapping (38.4% vs. 25.0%, p = 0.025). Among 65 patients who showed extra-PV at the repeat procedures, 19 (29.2%) matched with previous focal or empirical extra-PV ablation sites and 9 (13.8%) were multiple or unmappable sites. AF recurrence rates were significantly higher in both patients with extra-PV triggers after de novo procedures (Log-rank P <0.001; HR 1.93 [1.58-2.36], p= <0.001) and repeat procedures (Log-rank P <0.001, HR 1.87 [1.29-2.70], p= <0.001).

Conclusion

ISO provoked extra-PV triggers commonly found in AF patients with significant remodelling and previous empirical or focal extra-PV ablations. Existence of extra-PV triggers were independently associated with poorer rhythm outcome after both de novo and repeat AFCA. Denovo AF ablation outcome OverallExtra-PV triggers (-)Extra-PV triggers (+)p-value(n = 2151)(n = 1895)(n = 256)Age, yrs58.98 ± 10.9558.73 ± 11.0360.76 ± 10.200.006Male, (%)1550 ( 72.1)1389 ( 73.3)161 ( 62.9)0.001Follow up duration, month50.30 (37.71)51.65 (37.95)40.71 (34.58)<0.001Early recurrence (%)579 ( 27.8)455 ( 24.9)124 ( 48.4)<0.001Clinical recurrence (%)699 ( 33.6)584 ( 32.0)115 ( 44.9)<0.001Abstract Figure. AF free survival according to Extra PVT

Computational modeling for antiarrhythmic drugs for atrial fibrillation according to the genotypes

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by a grant [HI19C0114] from the Ministry of Health and Welfare. Additionally, the work was funded by grants [NRF-2019R1C1C100907512], and [NRF-2020R1A2B01001695] from the Basic Science Research Program run by the National Research Foundation of Korea (NRF) under the Ministry of Science, ICT & Future Planning (MSIP).

Background

The efficacy of antiarrhythmic drugs (AAD) can vary in patients with atrial fibrillation (AF) and the PITX2 gene affects the responsiveness of AADs. We explored the virtual AAD (V-AAD) responses between wild-type and PITX2+/- deficient AF conditions by realistic in-silico AF modeling.

Methods

We tested the V-AADs in AF modeling integrated with patients’ 3D-computed tomography and 3D-electroanatomical mapping, acquired in 25 patients (68% male, 59.8 ± 9.8 years old, 32.0% paroxysmal type). The ion currents for the PITX2+/- deficiency and each AAD (amiodarone, sotalol, dronedarone, flecainide, and propafenone) were defined based on previous publications.

Results

We compared the wild-type and PITX2+/- deficiency in terms of the action potential duration (APD90), conduction velocity (CV), maximal slope of restitution (Smax), and wave-dynamic parameters, such as the dominant frequency (DF), phase singularities (PS), and AF termination rates according to the V-AADs. The PITX2+/- deficient model exhibited a shorter APD90 (p < 0.001), a lower Smax (p < 0.001), mean DF (p = 0.012), PS number (p < 0.001), and a longer AF cycle length (AFCL, p = 0.011). Five V-AADs changed the electrophysiology in a dose dependent manner. AAD-induced AFCL lengthening (p < 0.001) and reductions in the CV (p = 0.033), peak DF (p < 0.001) and PS number (p < 0.001) were more significant in PITX2+/- deficient than wild-type AF. PITX2+/- deficient AF was easier to terminate with class IC AADs than the wild-type AF (p = 0.018).

Conclusions

The computational modeling-guided AAD test was feasible for evaluating the efficacy of multiple AADs in patients with AF. AF wave-dynamics and electrophysiological characteristics are different among the PITX2 deficient and the wild-type genotype models. BaselineChanges after AADClass ICClass IIIWild-typePITX2+/-p-valueWild-typePITX2+/-p-valueWild-typePITX2+/-p-valueWild-typePITX2+/-p-valueAPD90, (ms)243.7 ± 33.8184.4 ± 15.5<0.00138.2 ± 37.343.4 ± 56.20.223275.9 ± 43.5219.0 ± 39.2<0.001284.9 ± 32.8233.8 ± 71.4<0.001CV, (m/s)0.78 ± 0.320.70 ± 0.210.347-0.15 ± 0.18-0.20 ± 0.260.0330.63 ± 0.320.53 ± 0.300.0270.60 ± 0.360.43 ± 0.33<0.001Mean Smax0.787 ± 0.280.531 ± 0.18<0.0010.005 ± 0.260.115 ± 0.24<0.0010.828 ± 0.310.694 ± 0.320.0030.768 ± 0.320.608 ± 0.27<0.001Mean AFCL, (ms)146.96 ± 24.61164.78 ± 22.730.01122.62 ± 24.5537.92 ± 32.72<0.001165.44 ± 36.96190.85 ± 35.61<0.001169.05 ± 25.26203.35 ± 34.78<0.001Peak DF, (Hz)10.68 ± 2.9711.82 ± 3.340.211-2.98 ± 4.94-5.46 ± 4.66<0.00110.01 ± 4.397.23 ± 4.20<0.0016.30 ± 4.325.80 ± 4.070.301Mean DF, (Hz)6.80 ± 0.886.22 ± 0.710.012-1.95 ± 2.44-2.20 ± 1.990.2065.75 ± 1.784.53 ± 2.00<0.0014.14 ± 2.393.69 ± 2.000.077PS Number, (N)101086 ± 9608814150 ± 24778<0.001-59322 ± 99288-7409 ± 27856<0.00150579 ± 6523611568 ± 21868<0.00132951 ± 558643524 ± 8302<0.001PS Life Span, (ms)109.36 ± 113.90102.24 ± 226.640.889-24.87 ± 72.06-41.38 ± 126.350.073103.36 ± 180.6868.05 ± 162.790.14871.91 ± 141.8655.99 ± 217.970.454Table. Effects of AADs in the Wild-type and PITX2+/- Deficiency groupAbstract Figure. Wild-type vs. PITX2+/- baseline model

Long-term outcomes of empirical extra-pulmonary vein linear ablation in patients with persistent atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by grants [HI18C0070] and [HI19C0114] from the Korea Health 21 R&D Project, Ministry of Health and Welfare, and a grant [NRF-2020R1A2B01001695] from the Basic Science Research Program run by the National Research Foundation of Korea (NRF).

Background

Although extra-pulmonary vein (PV) left atrial (LA) linear ablation has been performed during catheter ablation (CA) of persistent atrial fibrillation (PeAF), the long-term efficacy and safety of this procedure have not yet been verified.

Purpose

We investigated whether an anterior line (AL) and posterior box ablation (POBA) in addition to circumferential PV isolation (CPVI) improves the rhythm without worsening the LA function in PeAF patients.

Methods

We retrospectively compared the additional AL + POBA and CPVI alone groups in 604 patients with PeAF who underwent regular rhythm follow-ups (16.9%; males 79.3%, 58.5 ± 10.7 years of age) after propensity score matching. The primary endpoint was AF recurrence after single procedures and secondary endpoints were the cardioversion rate, response to anti arrhythmic drugs, LA changes, and re-conduction rates of the de-novo ablation lesion set.

Results

After a mean follow-up of 45.2 ± 33.6 months, the clinical recurrence rate did not significantly differ between the two groups (log-rank p = 0.554) despite longer procedure times in the AL + POBA group (p < 0.001). Atrial tachycardia recurrences (p = 0.001) and the cardioversion rates after ablation (p < 0.001) were higher in the AL + POBA group than CPVI group. AL + POBA was associated with better rhythm outcomes in patients with large anterior LA volume indices (p for interaction 0.037) and low mean LAA(left atrial appendage) voltages (p for interaction 0.019). In repeat procedures, the LA pulse pressure elevation was significant after the AL + POBA.

Conclusion

In patients with PeAF, an AL + POBA in addition to the CPVI did not improve the rhythm outcomes nor influence the long-term safety, and lead to more extended procedures. Procedure outcomes OverallAL + POBACPVIp-value(n = 604)(n = 302)(n = 302)Procedure time, min190.8 ± 62.6226.9 ± 49.4154.6 ± 52.8<0.001Ablation time, sec5079 ± 19566420 ± 13723738± 1475<0.001Overall complications24 (4.0)13 (4.3)11 (3.6)0.835Early recurrence, n (%)277 (45.9)129 (42.7)148 (49.0)0.142Recurrence type AT, n (% in early recur)77 (27.8)51 (39.5)26 (17.6)<0.001Clinical recurrence within 1-year, n(%)116 (19.2)52 (17.2)65 (21.5)0.256Recurrence type AT, n (% in clinical recur)60 (23.1)46 (30.7)14 (12.7)0.001Cardioversion, n (% in total recur/ % overall)105 (40.4/17.4)74 (49.3/24.5)31 (28.1/10.3)<0.001POBA, posterior box ablation; AL, anterior line; CPVI, circumferential pulmonary vein isolation; AT, atrial tachycardia;Abstract Figure. Long term ablation outcome

P48 Exploration of variation in Management of Acutely Symptomatic Hernia – results from the MASH practice survey

Introduction

There is minimal evidence to guide the emergency management of groin and abdominal wall hernia. The aim of this project is to understand current variations in clinical practice across the UK when managing common types of acutely symptomatic hernia.

Methods

A survey of clinical practice was developed to explore the management of acutely symptomatic abdominal wall hernia (ASH) including groin (GH), umbilical (UH), and incisional hernia (IH). The survey captured respondent characteristics. It explored preferences in the management of each type of ASH, including factors related to treatment and repair strategy. Surgeons at ST3+ level with a UK practice were invited to participate through Twitter and collaborative networks.

Results

In total, 144 responses were received (response rate 26%). Of these, 62 (43.1%) were Consultant Surgeons, 105 (72.9%) did not have a specialist hernia practice, and 95 (66%) did not follow specific guidelines for emergency hernia repair. There was variation in investigations used e.g. CT required for IH (91%) but less for GH (34.7%) and UH (47.2%). Open repair was preferred in all settings. For GH with ischaemic bowel 76 (52.8%) would suture repair vs. 67 (46.5%) who would use a mesh (64.2% permanent synthetic) this is similar for IH, where 59 (41%) chose suture vs. 71 (49.3%) mesh, although 61.9% favoured biologic mesh for IH. Suture repair was preferred for UH with ischaemic bowel (69.4%).

Conclusion

The survey demonstrates variation in treatment of ASH. Areas which require further exploration include use of mesh and laparoscopy in the emergency setting.

Uncertainty studies on hydrogen source term with MAAP5 code

In the present study, a methodology is developed to quantify the uncertainties of special model parameters of the integral severe accident analysis code MAAP5. Here, the in-vessel hydrogen production during a core melt accident for Lungmen Nuclear Power Station of Taiwan Power Company, an advanced boiling water reactor, is analyzed. Sensitivity studies are performed to identify those parameters with an impact on the output parameter. For this, multiple calculations of MAAP5 are performed with input combinations generated from Latin Hypercube Sampling (LHS). The results are analyzed to determine the 95th percentile with 95% confidence level value of the amount of in-vessel hydrogen production. The calculations show that the default model options for IOXIDE and FGBYPA are recommended. The Pearson Correlation Coefficient (PCC) was used to determine the impact of model parameters on the target output parameters and showed that the three parameters TCLMAX, FCO, FOXBJ are highly influencing the in-vessel hydrogen generation. Suggestions of values of these three parameters are given.

161 Does the Weather Contribute to Admissions of Neck of Femur Fractures?

Introduction

The effects of weather on overall mortality are well documented. Anecdotally, icy conditions are perceived to result in more falls and admissions for neck of femur (NOF) fractures. The aim of this unfunded pilot study was to determine whether relationships could be extracted or at least not ruled out by analysing a small dataset, and so give impetus to a larger project.

Methods

Seven trauma units across north west London were identified and NOF fracture data extracted for five years. Visual inspection of the time series, consideration of the weather on specific days and correlation analysis were used to assess causal links between fracture numbers and a variety of weather parameters (temperature, rainfall, wind and ice risk).

Results

Overall, 10,929 individuals with hip fractures were admitted over the five-year period. The highest number of admissions in a day was 14. No clear association was found between a weather parameter and daily admissions. However, when accumulated to a weekly timescale, a negative relationship with maximum temperature was found. No seasonal cycle was detected.

Conclusion

The lack of a daily relationship and presence of a weekly relationship points to a possible delayed response to weather or insufficient daily data to extract a signal. The inconclusive results also indicate that more socioeconomic data will need to be used in future studies, requiring a larger data sample. In addition, even in cold weather an urban environment may not create icy conditions, being ameliorated by the heat island effect and gritting.

Dynamical ground state in the XY pyrochlore Yb2GaSbO7

The magnetic ground state of the pyrochlore Yb2GaSbO7 has remained an enigma for nearly a decade. The persistent spin fluctuations observed by muon spin relaxation measurements at low temperatures have not been adequately explained for this material using existing theories for quantum magnetism. Here we report on the synthesis and characterisation of Yb2GaSbO7 to elucidate the central physics at play. Through DC and AC magnetic susceptibility, heat capacity, and neutron scattering experiments, we observe evidence for a dynamical ground state that makes Yb2GaSbO7 a promising candidate for disorder-induced spin-liquid or spin-singlet behaviour. This state is quite fragile, being tuned to a splayed ferromagnet in a modest magnetic field μ 0 H c ∼ 1.5 T .

97 Function of species-specific OCT4 reporter system during porcine embryo development

The present study examined the activity and function of pig OCT4 (POU5F1) enhancer in porcine early embryo development. OCT4 is one of the master regulators for the pluripotency of early mammalian embryonic development and embryonic stem cells. It has two regulatory elements: distal enhancer (DE) and proximal enhancer (PE) in the upstream regulatory region. They are activated under different conditions such as naïve and primed. It is known that two enhancers are activated to produce OCT4 simultaneously or sequentially depending on the state of pluripotency. Many porcine OCT4 upstream region-based reporter systems have been reported because this is a necessary part of studying porcine-specific pluripotency. However, the porcine-specific OCT4 reporter system has never been transfected and functionally tested during porcine early embryo development. We performed functional tests of the previously established porcine-specific OCT4 reporter system in the early embryo development stage. Porcine embryos were micro-injected with the pOCT4-ΔPE-eGFP (DE-GFP) containing a distal enhancer and core promoter and pOCT4-ΔDE-DsRed2 (PE-RFP) containing a proximal enhancer and core promoter. They were cultured in PZM-3 at 39°C in a humidified atmosphere, 5% CO2, and 5% O2 for 168h. Fifty of the 100 embryos were injected with OCT4 reporter system as treatment groups and the other 50 were not injected (control groups). We analysed mRNA and protein expression of GFP and RFP using quantitative real-time PCR and confocal microscopy by developmental stages. The introduced reporter system could function beginning with the 4-cell stage. The expression of GFP and RFP was observed simultaneously in the early embryonic development stage up to blastocyst, indicating that porcine OCT4 was produced by distal and proximal enhancers, unlike mouse Oct4 expression, which was only controlled by the distal enhancer during early embryo development. Therefore, the mechanisms and functions of distal and proximal enhancers of porcine OCT4 were different from those of the mouse. This is similar to results of the previous experiment using porcine-induced pluripotent stem cells, which suggest that porcine OCT4 is expressed by two enhancers and in a stage-specific manner during reprogramming and that pigs do not use only one enhancer in pluripotent states, but two enhancers at the same time, and there is only a difference in degree. This work showed that the porcine OCT4 reporter system enables non-destructive analysis during early embryo development and it could be applied to study species-specific pluripotency and to help the establishment of naïve embryonic stem cells in the pig. This work was supported by the BK21 Plus Program, the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF-2019R1C1C1004514), the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry (IPET) through the Development of High Value-Added Food Technology Program funded by the Ministry of Agriculture, Food, and Rural Affairs (MAFRA; 118042-03-3-HD020).