O5: THE CLIFF AND CONOR STUDIES NOVEL ASSESSMENT TOOLS IN COLORECTAL LIVER METASTASES (CLIFF STUDY - CHANGE IN LIVER FUNCTION AND FAT IN PRE-OPERATIVE CHEMOTHERAPY FOR COLORECTAL LIVER METASTASES, CONOR STUDY

Introduction

Hepatic resection is the only potentially curative treatment for patients with colorectal liver metastases (CLM). Patient selection is key, but there is wide variation in practice. Pre-operative chemotherapy can improve oncological outcomes, however chemotherapy-associated liver injury (CALI) may hinder liver regenerative capacity. Standard pre-operative assessments fail to accurately capture factors such as CALI and future liver remnant (FLR) function. The CLiFF and CoNoR studies utilise two novel assessment techniques, aiming to improve patient outcomes.

Method

The CLiFF study prospectively assesses two primary outcomes in 35 patients undergoing pre-operative chemotherapy for CLM: 1) change in liver function (via LiMAx test: direct assessment of hepatic functional capacity), and 2) change in liver fat (via advanced MR imaging (in-house spectroscopy and modified Dixon technique, scaled up via Perspectum LiverMultiScan)). The CoNoR study assesses potential added benefit of these novel tools in CLM resectability decision-making via sequential workstreams: a systematic review and international hepatobiliary expert interviews inform the online survey, assessing added benefit via online MDT scenarios.

Result

Preliminary CLiFF analysis suggests that CALI changes in liver fat and function are unrelated. Liver fat analysis techniques are compared and correlated with digital histological analysis. The CoNoR systematic review identifies key factors influencing CLM resectability decision-making and informs the international expert interviews, scheduled to occur during a February 2020 international hepatobiliary conference.

Conclusion

These studies are the first to assess where these novel tools might be utilised to maximal patient benefit within the Hepatobiliary MDT, and the first systematic review in CLM resectability decision-making.

Take-home message

These two linked studies evaluate the use of two novel assessment tools in the treatment of colorectal liver metastases, with the potential to improve patient selection for curative resection and patient outcomes.

PATEY PRIZE SESSION

Comparison between measurement and calculations for a 14 MeV neutron water activation experiment

The nuclear heat loads due to gamma rays emitted from the decay of 16N and delayed neutrons from17N, generated by the activation of water in cooling circuits, are critical for ITER design. The assessment of nuclear heating from activated water is complex; it requires temporal and spatial dependent transport and activation calculations taking into account variation of irradiation, water flow conditions and cooling circuits’ parameters. A water activation experiment has been recently conducted at the14 MeV Frascati Neutron Generator (FNG) in order to validate the methodology for water activation assessment used for ITER and to reduce the safety factors applied to the calculation results, which have a large impact on the schedule, commissioning and licensing. Water circulating inside an ITER First Wall (FW) mock-up was irradiated with 14 MeV neutrons and then measured using a large CsI scintillator detector. The system consists of a closed water loop where the cooling water, transiting through an ITER FW mock-up, is irradiated by FNG. The induced 16N activity via 14 MeV neutrons interactions with 16O via the 16O(n,p)16N reaction is measured in a dedicated counting station via an expansion volume. The water then passes to a much larger holding delay tank, and after several 16N half-lives decay time, it is then recirculated and exposed again to neutrons in the ITER First Wall (FW) mock-up. The measured 16N activity is obtained measuring the emitted characteristic 6.13 and 7.12 MeV gamma-rays. Calculations were performed in an accurate model of the FW mock-up using the MCNP Monte Carlo code and FENDL-3.1 nuclear data library to obtain the predicted flux impinging on the water. The EASY-2007 inventory code was used to predict the 16N activity. In this work, a comparison between measurements and calculations is reported together with associated uncertainty analysis.

OVERVIEW OF NEUTRON MEASUREMENTS IN JET FUSION DEVICE

The design and operation of ITER experimental fusion reactor requires the development of neutron measurement techniques and numerical tools to derive the fusion power and the radiation field in the device and in the surrounding areas. Nuclear analyses provide essential input to the conceptual design, optimisation, engineering and safety case in ITER and power plant studies. The required radiation transport calculations are extremely challenging because of the large physical extent of the reactor plant, the complexity of the geometry, and the combination of deep penetration and streaming paths. This article reports the experimental activities which are carried-out at JET to validate the neutronics measurements methods and numerical tools used in ITER and power plant design. A new deuterium-tritium campaign is proposed in 2019 at JET: the unique 14 MeV neutron yields produced will be exploited as much as possible to validate measurement techniques, codes, procedures and data currently used in ITER design thus reducing the related uncertainties and the associated risks in the machine operation.

Using administrative data for primary care research: the City and East London General Practice Database Project

The City and East London General Practice Database Project was launched in 1992 to provide a framework for describing and understanding the nature of general practice in east London using routinely available administrative data from all practices in the area. It has provided an opportunity to use information on practices for research, health planning and policy, and for educational purposes. The project differs from others because it allows description in detail, clarity and depth in three distinct ways. Firstly, by covering all practices, and not just a select group, it is possible to investigate intra-health authority variability. Secondly, it has taken into account social and demographic characteristics of the practice populations, so making it possible to examine practice outputs in relation to population deprivation. Thirdly, in time, analyses using a combination of patient outcomes, morbidity information and longitudinal data become possible, making it an even more powerful information base for commissioning.

Mutual information as a measure of image quality for 3D dynamic lung imaging with EIT

We report on a pilot study of dynamic lung electrical impedance tomography (EIT) at the University of Manchester. Low-noise EIT data at 100 frames per second were obtained from healthy male subjects during controlled breathing, followed by magnetic resonance imaging (MRI) subsequently used for spatial validation of the EIT reconstruction. The torso surface in the MR image and electrode positions obtained using MRI fiducial markers informed the construction of a 3D finite element model extruded along the caudal-distal axis of the subject. Small changes in the boundary that occur during respiration were accounted for by incorporating the sensitivity with respect to boundary shape into a robust temporal difference reconstruction algorithm. EIT and MRI images were co-registered using the open source medical imaging software, 3D Slicer. A quantitative comparison of quality of different EIT reconstructions was achieved through calculation of the mutual information with a lung-segmented MR image. EIT reconstructions using a linear shape correction algorithm reduced boundary image artefacts, yielding better contrast of the lungs, and had 10% greater mutual information compared with a standard linear EIT reconstruction.

Comparison of dynamic contrast-enhanced MRI and dynamic contrast-enhanced CT biomarkers in bladder cancer

Dynamic contrast-enhanced MRI (DCE-MRI) is frequently used to provide response biomarkers in clinical trials of novel cancer therapeutics but assessment of their physiological accuracy is difficult. DCE-CT provides an independent probe of similar pharmacokinetic processes and may be modeled in the same way as DCE-MRI to provide purportedly equivalent physiological parameters. In this study, DCE-MRI and DCE-CT were directly compared in subjects with primary bladder cancer to assess the degree to which the model parameters report modeled physiology rather than artefacts of the measurement technique and to determine the interchangeability of the techniques in a clinical trial setting. The biomarker K(trans) obtained by fitting an extended version of the Kety model voxelwise to both DCE-MRI and DCE-CT data was in excellent agreement (mean across subjects was 0.085 ± 0.030 min(-1) for DCE-MRI and 0.087 ± 0.033 min(-1) for DCE-CT, intermodality coefficient of variation 9%). The parameter v(p) derived from DCE-CT was significantly greater than that derived from DCE-MRI (0.018 ± 0.006 compared to 0.009 ± 0.008, P = 0.0007) and v(e) was in reasonable agreement only for low values. The study provides evidence that the biomarker K(trans) is a robust parameter indicative of the underlying physiology and relatively independent of the method of measurement.

MR measurement of articular cartilage thickness distribution in the hip

OBJECTIVE

To develop a method to determine the distribution of articular cartilage in the hip and to evaluate the potential of the method in a study of normal weight-bearing effects in asymptomatic young volunteers.

DESIGN

Six volunteers were scanned after periods of standing and lying supine, using 3D gradient-echo magnetic resonance imaging (MRI). The protocol was repeated for two successive weeks to determine reproducibility. The femoral and acetabular cartilage layers were segmented as a single unit and thickness distribution maps were calculated using a spherical bone model as a frame of reference. Thickness maps were combined over the population using the bone model and post-weight-bearing and post-resting maps were compared.

RESULTS

Mean thickness values were compared using an analysis of variance and a significant increase in cartilage thickness of 0.05 mm (P=0.02) was observed. The reproducibility of the method, assessed using test-retest coefficient of variation was 2.5%.

CONCLUSIONS

The technique is reproducible, sensitive to sub-millimetre changes in thickness and may be useful in monitoring changes due to disease progression in patients with arthritis of the hip.

Did the London Initiative Zone investment programme affect general practice structure and performance in East London? A time series analysis of cervical screening coverage and asthma prescribing

A programme of incentives was set up in the London Initiative Zones to improve primary care in inner London based on the findings of the Tomlinson Enquiry in 1992. This descriptive study is a 4-y time series analysis of changes in general practice structure in East London as the result of London Initiative Zone investment, and an exploration of the possible effect of investment on practice performance. We used routinely available administrative data for the whole analysis. General practice characteristics and two selected performance indicators: the asthma prophylaxis to bronchodilator ratio and cervical cytology screening rate, for all practices in the East London and the City Health Authority for 4 y, 1993-1996, were used. Both reflect practice efficiency, but relate to different aspects of practice performance. The prescribing indicator is more indicative of the quality of clinical practise, whereas cervical screening coverage relates more to the characteristics of the practice population and to practice organisation. Repeated measures analyses were used to identify trends and to explore the relationship between changes in practice characteristics and performance. Graphical methods were used to compare East London trends with the rest of England. There were significant improvements in practice structure as the consequence of London Initiative Zone investment. There was a positive association with improvements in practice performance, but East London still lagged some way behind national patterns. The findings suggest that while improvements in asthma prescribing follow the national trend, practices have difficulty in achieving and sustaining the 80% target for cervical cytology screening, and that an overall population coverage of 80% may be in doubt.Increased investment in practice staffing may be influential in improving some aspects of performance. However, in common with other inner cities, a greater effort and more innovative strategies may be needed to achieve a standard of performance equal to the best.

Do practice-based preventive child health services affect the use of hospitals? A cross-sectional study of hospital use by children in east London

BACKGROUND

Acute paediatric admissions have risen steadily over the past 20 years. During the same period, practice-based child health clinics have increased, although provision is less common in areas of deprivation where hospital use is greatest.

AIM

To investigate the contribution of practice-based, preventive child health services to rates of hospital utilisation in children under five years of age.

METHOD

A cross-sectional retrospective study examining practice variations in paediatric acute admissions, outpatient referrals, and accident and emergency (A&E) department attendances in the East London and the City Health authority, including all 164 practices in the inner-city boroughs of Hackney, Newham, Tower Hamlets, and the City of London. The main outcome measures were practice-based paediatric hospital attendance rates, for discrete age and sex bands, for the year to 31 March 1996.

RESULTS

Hospital use varied with age and sex, with the rates being highest for the youngest children and for boys. The median A&E attendance rate (including reattendances) for boys up to one year of age was 897 per thousand children per practice. In east London, 62% of practices are registered for child health surveillance and 71% provide a child health clinic. Practice approval for child health surveillance, and the provision of child health clinics, did not account for differences between practices in hospital use, but proportionally greater health visiting hours were significantly related to lower rates of emergency hospital admission by young children. Multivariate analyses revealed that up to 23% of the variation between practice admission rates could be explained by health visiting hours.

CONCLUSIONS

We found significant associations between the amount of health visiting time available to the practice population and rates of acute admission and outpatient referral among children up to five years of age. These findings suggest that increasing health visitor provision could contribute to lower paediatric emergency admission and outpatient referral rates. A small change would have a significant effect, particularly among the youngest children, given that during the study year 10,000 children under two years of age in east London were either admitted or referred to hospital.

Prescribing for persistent cough in children

To identify the medications general practitioners consider for the treatment of persistent isolated cough, we undertook a postal questionnaire survey of a sample of general practitioners in east London. Fewer than 10% indicated that they never prescribed for such cough. About 70% sometimes considered antibiotics and/or bronchodilators in all age groups. Inhaled steroids and cromoglycate were considered by about 30% of prescribers for infants compared with over 60% for older age groups. As yet there is no evidence that medication is beneficial for persistent isolated cough. The role of asthma drugs for children with this symptom needs to be evaluated so that we can better identify those who are likely to benefit.

Hospital admissions for asthma in east London: associations with characteristics of local general practices, prescribing, and population

OBJECTIVE

To determine the relative importance of appropriate prescribing for asthma in explaining high rates of hospital admission for asthma among east London general practices.

DESIGN

Poisson regression analysis describing relation of each general practice's admission rates for asthma with prescribing for asthma and characteristics of general practitioners, practices, and practice populations.

SETTING

East London, a deprived inner city area with high admission rates for asthma.

SUBJECTS

All 163 general practices in East London and the City Health Authority (complete data available for 124 practices).

MAIN OUTCOME MEASURES

Admission rates for asthma, excluding readmissions, for ages 5-64 years; ratio of asthma prophylaxis to bronchodilator prescribing; selected characteristics of general practitioners, practices, and practice populations.

RESULTS

Median admission rate for asthma was 0.9 (range 0-3.6) per 1000 patients per year. Higher admission rates were most strongly associated with small size of practice partnership: admission rates of singlehanded and two partner practices were higher than those of practices with three or more principals by 1.7 times (95% confidence interval 1.4 to 2.0, P < 0.001) and 1.3 times (1.1 to 1.6, P = 0.001) respectively. Practices with higher rates of night visits also had significantly higher admission rates: an increase in night visiting rate by 10 visits per 1000 patients over two years was associated with an increase in admission rates for asthma by 4% (1% to 7%). These associations were independent of asthma prescribing ratios, measures of practice resources, and characteristics of practice populations.

CONCLUSIONS

Higher asthma admission rates in east London practices were most strongly associated with smaller partnership size and higher rates of night visiting. Evaluating ways of helping smaller partnerships develop structured proactive care for asthma patients at high risk of admission is a priority.