Pancreas: An Organ-at-Risk to Consider in Future Pediatric Abdominal Radiotherapy

PURPOSE/OBJECTIVE(S)

Irradiation to the pancreas during pediatric radiotherapy is associated with secondary late effects, yet the pancreas is not typically considered an organ-at-risk (OAR) during radiotherapy planning. This audit investigated incidental pancreatic doses to estimate the relative risk (RR) of developing diabetes in later life.

MATERIALS/METHODS

Incidental pancreas doses were audited from 92 patients aged 2 to 19 historically treated with photons for craniospinal irradiation (CSI, N = 73) and for abdominal neuroblastoma (N = 19). Prescription doses ranged 21-36 Gy and 21-39 Gy (with boost to spine up to 50 Gy) for neuroblastoma and CSI patients, respectively. The pancreas was segmented on all planning CT scans following RTOG guidelines. Furthermore, the pancreas was split into its sub-volumes (head, body and tail) for abdominal cases only, since these scans were acquired with contrast enhancement. The RR of developing subsequent diabetes was estimated as a function of dose (D): RR = 1+0.65 × D × exp(-0.3 × D). Dose to the pancreas tail was used for neuroblastoma cases, whereas dose to the whole pancreas was used for CSI patients given that the pancreas could not be split in non-contrast scans.

RESULTS

The mean dose delivered to the whole pancreas was 15.4±7.5 Gy for all patients, 12.7±4.7 Gy for CSI patients and 25.9±7.4 Gy for abdominal patients. Pancreas V10Gy was 61.2% for all patients, 51.5% for CSI, and 98.6% for abdominal patients; V30Gy = 0% in all cases. These doses represented an estimated diabetes RR of 7.3±1.5, 6.6±1.3, and 8.7±0.6, respectively; RR>5 in 88%, 85% and 100% of all patients, CSI and abdominal patients audited, respectively.

CONCLUSION

Current incidental doses were associated with a diabetes RR>5 in all patients treated for abdominal neuroblastoma and the majority who received CSI. These findings suggest the pancreas should be routinely delineated and considered as an OAR in radiotherapy planning. This may help to identify higher risk patients and inform late-effect monitoring during survivorship. Further work in underway to assess if proton therapy could reduce the RR of diabetes particularly in abdominal cases. Improved availability of high-quality imaging during radiotherapy planning, such as contrast administration or planning MRI, is becoming more necessary to accurately delineate subsegments of the pancreas for improved RR estimations.

Evaluation of Radiotherapy Dose and Survival Outcomes for Teenagers, and Young Adults with Nasopharyngeal Carcinoma in UK and Ireland

PURPOSE/OBJECTIVE(S)

Nasopharyngeal carcinoma (NPC) follows a bimodal distribution with a smaller incidence peak in teenagers and young adults (TYAs). In TYAs, an over-whelming proportion are associated with Epstein-Barr virus (EBV). We have evaluated the variation in TYA NPC practice patterns across the UK and Ireland, along with survival outcomes.

MATERIALS/METHODS

We performed a multicenter, observational cohort study, of patients aged 13-25 years, with histologically confirmed NPC, treated between the years 2002-2022. An initial expression of interest was sent to selected centers treating H&N patients in the UK and Ireland. For analysis, patients were assessed based on total prescribed dose, with a cut off for low dose (LD) (≤61.2Gy) versus a high dose (HD)(>61.2Gy).

RESULTS

Ninety-five patients, from 9 centers, were eligible for inclusion. Patient demographics are shown in table1. At a median follow up of 45 months (IQR 23-111), 3-year overall survival (OS) was 98% (95% CI 93%-100%) with LD versus 91% (95% CI 83%-99%) with HD (Hazard ratio (HR) = 3.0; 95% CI 0.3-27, p = 0.3). 3-year progression free survival (PFS) was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6), and 5-year PFS was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6). Incidence of distant metastasis (DM) was 9.9%. 2 patients (6%) with T3-T4 tumors, treated with LD, had locoregional failure (LRF) compared to 1 patient (3%) treated with HD.

CONCLUSION

We have demonstrated excellent survival outcomes for the UK & Ireland TYA NPC patients. As the majority of cases in this age group have EBV+ NPC, with survival similar between LD and HD protocols, we propose that pediatric protocols, with lower radiotherapy doses should be considered for all TYA NPC, with the aim of reducing late effects. Additional analysis to better understand the impact of heterogeneity between both groups, including choice of protocol, induction and adjuvant treatment will follow this study. Prospective evaluation, as part of an international collaboration, is required to optimize the management strategy for this rare cohort of patients.

Development of Population-Based Pediatric Computational Phantoms for Radiotherapy Applications

PURPOSE/OBJECTIVE(S)

Age-specific pediatric computational phantoms are used in radiotherapy (RT) for quality assurance and for reconstruction of historical RT doses (within others). Phantoms are typically developed from healthy patients and may not effectively represent those with cancer due to pathology and/or treatment effects. This study evaluated a set of population-based pediatric computational phantoms developed in-house in terms of anatomical plausibility.

MATERIALS/METHODS

Planning CTs and contours from historical craniospinal irradiation (CSI) patients (n = 74, median age 7y, range: 1-17y) were used to generate and evaluate a set of in-house age-specific population-based RT phantoms (RT-P). The RT-P were generated by combining a sub-set of clinical CTs and contours through groupwise deformable image registration, generating average models of CSI sub-populations (n = 74, median age 7y, range: 3-14y). Models were then compared against clinical data and two libraries of phantoms representing healthy populations: the International Commission on Radiological Protection (ICRP) pediatric reference computational phantoms (n = 8, median age 8y, range: 1-15y) and a variety of default 4D extended cardiac torso (XCAT) phantoms (n = 75, median age 9y, range: 1-18y). Variation between organ volumes for the different datasets was assessed through a linear fit of organ volume with age, reporting the slope (∑) of each fit [y-1]. Average difference between the volume datapoints and the linear fit for clinical data (Δ) [%] were also reported. This allowed for comparisons of the RT-P to clinical and reference data in terms of organ volumes across developmental stages.

RESULTS

The table shows 9 of the 19 investigated organs. The ∑ reported for RT-P models were of similar magnitude as the clinical data and other phantoms, effectively modelling changes with age. The greatest and least ∑ were reported from lungs and thyroid respectively, in agreement with expected relative sizes between organs. Larger values for Δ were likely due to differences in organ filling and segmentation strategy between datasets, limitations of RT-P methodology, and/or anatomical differences between healthy and cancer populations.

CONCLUSION

The RT-P models show promise in representing the RT cohort that may benefit from specialized anatomical phantoms. Further work is needed to address the limitations of the current methodology and its applicability to other RT cohorts.

A National Referral Service for Paediatric Brachytherapy: An Evolving Practice and Outcomes Over 13 Years

AIMS

Most children requiring radiotherapy receive external beam treatment and few have tumours suitable for brachytherapy. No paediatric radiotherapy centre will treat enough patients from its own normal catchment population for expertise in brachytherapy to be developed and sustained. Following discussion and agreement in the national paediatric radiotherapy group, a service for paediatric brachytherapy in the UK has been developed. We report the process that has evolved over more than 10 years, with survival and functional outcome results.

MATERIALS AND METHODS

Since 2009, potential patients have been referred to the central paediatric oncology multidisciplinary team meeting, where imaging, pathology and treatment options are discussed. Since 2013, the National Soft Tissue Sarcoma Advisory Panel has also reviewed most patients, with the principal aim of advising on the most suitable primary tumour management for complex patients. Clinical assessment and examination under anaesthetic with biopsies may be undertaken to confirm the appropriateness of brachytherapy, either alone or following conservative surgery. Fractionated high dose rate brachytherapy was delivered to a computed tomography planned volume after implantation of catheters under ultrasound imaging guidance. Since 2019, follow-up has been in a dedicated multidisciplinary clinic.

RESULTS

From 2009 to 2021 inclusive, 35 patients (16 female, 19 male, aged 8 months to 17 years 6 months) have been treated. Histology was soft-tissue sarcoma in 33 patients and carcinoma in two. The treated site was pelvic in 31 patients and head and neck in four. With a median follow-up of 5 years, the local control and overall survival rates are 100%. Complications have been few, and functional outcome is good.

CONCLUSION

Brachytherapy is effective for selected paediatric patients, resulting in excellent tumour control and good functional results. It is feasible to deliver paediatric brachytherapy at a single centre within a national referral service.

P-066 ABDOMINAL WALL RECONSTRUCTION FOLLOWING FULL THICKNESS BILATERAL RUPTURE OF THE RECTUS ABDOMINIS

Introduction

Rupture of the rectus abdominis is rare injury with no consensus on management. Previous reported cases have been due to exercise-related injuries and blunt abdominal trauma. We report the case of a 20-year-old male trainee paratrooper who presented with severe lower abdominal pain that occurred during military training. MRI revealed full-thickness bilateral rupture of the rectus abdominis. Abdominal wall reconstruction involved bilateral rectus muscle repair and placement of a biosynthetic mesh in the retrorectus plane. Postoperatively, our patient could walk pain-free at 3 weeks, jog pain-free at 10 weeks, and run up to 2 miles at 25 weeks.

Methods

Pubmed, Medline and Embase were searched to identify relevant studies using the MeSH terms, “rectus abdominis” and “rupture”, as well as their free text counterparts and synonyms. Texts were restricted to publications in English and publications after the year 2000. The search resulted in 391 articles. Manual cross-referencing was performed, limiting the included articles to 8 for review.

Results

6 out of the 8 selected articles discussed management using conservative means, while only 2 cases were managed surgically. Interestingly, no other exercise-related cases in the literature were managed surgically. Instead, all exercise related cases were managed conservatively, while only cases of traumatic aetiology were managed surgically. Among both surgically and conservatively treated patients, none suffered any treatment related complications, and all patients returned to normal levels of activity.

Conclusion

Full-thickness, bilateral rupture of the rectus abdominis can occur during exercise. Surgical and conservative treatment yield similar results.

602 Using Plastic Surgery Techniques in Abdominal Wall Surgery

Complex Abdominal Wall Hernias (CAWH) present a huge challenge to surgeons and patients often requiring Abdominal Wall Reconstruction (AWR). AWR aims to restore abdominal wall anatomy, improve function, and reduce the risk of future herniation. Plastic surgery techniques can be used including primary closure, skin grafts, flaps, tissue expansion and small bite, small stitch technique. Below are two cases where some of these techniques were utilised.

Case 1

LC is a 65 y/o female with CAWH. Her gastric band became infected requiring a laparotomy for perforation of gastroesophageal junction. She subsequently had primary open repair of abdominal hernia using Permacol. It became infected requiring 5 debridements and application of a VAC device. Her hernia was a Ventral Hernia Working Group (VHWG) grade 3 at 10cm×16cm. Her CAWH was repaired using a Rives-Stoppa technique and a Surgimend mesh. The epigastric component of her wound was closed using a superiorly based local rhomboid flap and a Prevena VAC dressing.

Case 2

KH is a 37 y/o female with a para-ileal conduit skin granuloma that was painful and refractory to other treatments such as silver nitrate and steroid topical treatments. She had excision of the area of granulation and her wound was closed using a local advancement flap taking account of previous scars raised and a prevena VAC dressing.

Discussion

CAWH requiring AWR is a complex operation benefiting from plastic surgical specialists. Plastic surgical techniques can help with closure of the abdominal wall and reduce complication rates including wound infections and incisional hernia.

688 Cancellation Rate of Prostate Template Biopsy: Are There Any Merits to Implementing Pre-Operative Bowel Preparations?

Introduction

The aim of this quality improvement project was to analyse the cancellation rates of the template biopsy done at the George Eliot Hospital. The focus was mainly on those due to poor bowel prep whereby manual evacuations have failed. Locally we have sometimes noted the failure rate of transperineal prostate biopsy as a result of the poor quality of the ultrasound due to inadequately evacuated rectum. Unfortunately, there are very limited studies which have looked into this issue hence the significance of this problem is not universally acknowledged.

Method

Retrospective review of all the template biopsies that were planned from April 2019 to April 2020 using the operation notes and local theatre management software.

Results

There was a total of 105 planned template biopsies from April 2019 to April 2020. 72 cases were attempted and within this, 7 of these cases required manual evacuations in which 3 resulted in abandonment of procedure. There were 33 cases which were cancelled due various other reasons.

Conclusions

The results showed that the failure rates due to poor bowel prep were not significant (4%). Based on these findings we have decided not to proceed with the implementation of pre-operative bowel prep with phosphate enema as we felt that the potential benefits were not enough for it be initiated as a routine practice. We aim to address the other reasons identified for cancellations.

Microdiversity of Enterococcus faecalis isolates in cases of infective endocarditis: selection of non-synonymous mutations and large deletions is associated with phenotypic modifications

Context: Today, infective endocarditis (IE) caused by Enterococcus faecalis represents 10% of all IE and is marked by its difficult management and the frequency of relapses. Although the precise reasons for that remain to be elucidated, the evolution of the culprit strain under selective pressure through microdiversification could be, at least in part, involved. Material and methods: To further study the in situ genetic microdiversity and its possible phenotypic manifestations in E. faecalis IE, we sequenced and compared multiple isolates from the valves, blood culture and joint fluid of five patients who underwent valvular surgery. Growth rate and early biofilm production of selected isolates were also compared. Results: By sequencing a total of 58 E. faecalis genomes, we detected a considerable genomic microdiversity, not only among strains from different anatomical origins, but also between isolates from the same studied cardiac valves. Interestingly, deletions of thousands of bases including the well-known virulence factors ebpA/B/C, and srtC, as well as other large prophage sequences containing genes coding for proteins implicated in platelet binding (PlbA and PlbB) were evidenced. The study of mutations helped unveil common patterns in genes related to the cell cycle as well as central metabolism, suggesting an evolutionary convergence in these isolates. As expected, such modifications were associated with a significant impact on the in-vitro phenotypic heterogeneity, growth, and early biofilm production. Conclusion: Genome modifications associated with phenotypic variations may allow bacterial adaptation to both antibiotic and immune selective pressures, and thus promote relapses.

A structured pathway for developing your complex abdominal hernia service: our York pathway

PURPOSE

Clinical pathways are widely prevalent in health care and may be associated with increased clinical efficacy, improved patient care, streamlining of services, while providing clarity on patient management. Such pathways are well established in several branches of healthcare services but, to the authors' knowledge, not in complex abdominal wall reconstruction (CAWR). A stepwise, structured and comprehensive approach to managing complex abdominal wall hernia (CAWH) patients, which has been successfully implemented in our practice, is presented.

METHODS

A literature search of common databases including Embase® and MEDLINE® for CAWH pathways identified no comprehensive pathway. We therefore undertook a reiterative process to develop the York Abdominal Wall Unit (YAWU) through examination of current evidence and logic to produce a pragmatic redesign of our own pathway. Having introduced our pathway, we then performed a retrospective analysis of the complexity and number of abdominal wall cases performed in our trust over time.

RESULTS

We describe our pathway and demonstrate that the percentage of cases and their complexity, as defined by the VHWG classification, have increased over time in York Abdominal Wall Unit.

CONCLUSION

A structured pathway for complex abdominal wall hernia service is one way to improve patient experience and streamline services. The relevance of pathways for the hernia surgeon is discussed alongside this pathway. This may provide a useful guide to those wishing to establish similar personalised pathways within their own units and allow them to expand their service.

[SARS-COV-2 myocarditis. An update]

The outbreak of the SARS-CoV-2 virus responsible for the COVID-19 disease has given rise to a new disease whose boundaries are still to be discovered. While the first data suggested a purely respiratory infection, the most recent publications highlight a large pleomorphism of the disease, responsible for multiple organ damage, of which cardiac injury seems to be the most represented. This cardiac injury can present as acute myocarditis. Our aim was to discuss the pathophysiological rationale underlying the existence of SARS-CoV-2 myocarditis and to analyze the literature data regarding the diagnosis and treatment of this particular entity.

Correlates and prognostic impact of acute heart failure at the acute stage of ST-elevation and non-ST-elevation myocardial infarction according to diabetic status: the FAST-MI registries

Background

Diabetes mellitus (DM) predisposes to cardiovascular diseases including acute myocardial infarction (AMI) and acute heart failure (AHF).

Purpose

Analysing the French Registries of Acute ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI) 2005 and 2010, we assessed correlates of AHF occurring at the acute stage of ST-elevation AMI (STEMI) and non-ST-elevation AMI (NSTEMI), as well as the prognostic impact of AHF on 5-year mortality according to diabetic status.

Methods

The FAST-MI 2005 and 2010 registries included 7,839 consecutive patients admitted for AMI (4,250 STEMI and 3,589 NSTEMI). Vital status at 5 years was available in >96% of the patients. Binary logistic regression analysis was used to determine independent correlates of AHF and Cox multivariate analysis was used to determine independent correlates of 5-year mortality. Long-term survival curves were estimated using the Kaplan Meier method and comparisons were made using log-rank tests.

Results

2,151 patients presented with DM (27,4%) and 629 patients (8,0%) were treated by insulin (DMi). DM patients were older (70.0 vs. 64.6 years; p<0.001), with more comorbidities and more severe coronary artery disease. AHF (pulmonary edema or cardiogenic shock) was the most frequent in-hospital complication (12.5%) and was twice as frequent in DM patients (20.2% vs. 9.6%; adjusted OR=1.66; 95% confidence interval: 1.43–1.94; P<0.001). AHF was more frequently observed in DM patients on insulin therapy compared with DM patients not receiving insulin (29.1% vs 16.6%; adjusted OR=1.53; 95% CI: 1.20–1.96; P=0.001). The significant difference in AHF between DM patients and patients without DM was found in both STEMI (18.8% vs 8.0%; P=0.001) and in NSTEMI (21.3% vs 11.9%; P=0.001) patients.

After multivariate analysis on confounders (risk factors, previous medical history, type of AMI, year of survey and medications used before the index AMI), compared with patients without DM nor AHF, those with AHF without DM and those with DM without AHF had a 50% increase in 5-year mortality (adjusted HR=1.50; 95% CI: 1.32–1.69; P<0.001 and adjusted HR=1.46; 95% CI: 1.23–1.74; P<0.001) while the risk of 5-year death was doubled in those with both DM and AHF (adjusted HR=1.97; 95% CI: 1.66–2.34; P<0.0001).

Conclusion

AHF is the most frequent complication of AMI and is twice as common in DM patients. It is associated with reduced 5-year survival in non-diabetic and DM patients, with the worst outcomes in patients with both conditions (AHF and DM). In AMI, new management strategies are needed to prevent AHF and improve survival in DM patients with AHF.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The FAST-MI 2005 and 2010 registries are the propriety of the French Society of Cardiology and were funded by grants from the following companies: Amgen, AstraZeneca, Bayer, BMS, Daiichi-Sankyo, Eli-Lilly, GSK, MSD, Novartis, Pfizer, Sanofi, and Servier, and by a grant from the French National Health Insurance body (CNAM-TS).

A multistage process leading to the development of a structured consent form and patient information leaflet for complex abdominal wall reconstruction (CAWR)

PURPOSE

Informed consent is vital in surgery. The General Medical Council, UK and Royal College of Surgeons of England provide clear guidance on what constitutes the process of informed patient consent. Despite this, evidence suggests that the consent process may not be performed well in surgery. We utilised a staged patient-centred approach and rigorous methodology to develop a standardised patient information leaflet (PIL) and pre-written structured consent form for complex abdominal wall reconstruction (CAWR).

METHODS

We utilised the principles of Deming's Plan-Do-Study-Act (PDSA) cycles to approach the process. Buzan's mind maps were used to identify the stakeholders and deficiencies in the consent process ('Plan' phase). The content of the PIL and pre-written consent form was then developed in collaboration with stakeholders ('Do' phase). Multidisciplinary and multidepartmental feedback was obtained on the proposed content and amendments were made ('Study' and 'Act' phases).

RESULTS

We successfully produced a clear, focused PIL and structured consent form, in Plain English, presenting accurate, relevant and detailed information in a highly understandable way. The PIL had a Flesch Reading Ease score of > 80, demonstrating a high level of readability and comprehensibility, with positive implications for informed patient decision making and preparedness for surgery.

CONCLUSION

Through sharing the process that we undertook, we aim to support other abdominal wall units who wish to develop and improve their own consent process.

Evaluation of dual energy CT and iterative metal artefact reduction (iMAR) for artefact reduction in radiation therapy

Metal artefacts pose a common problem in single energy computed tomography (SECT) images used for radiotherapy. Virtual monoenergetic (VME) images constructed with dual energy computed tomography (DECT) scans can be used to reduce beam hardening artefacts. Dual energy metal artefact reduction is compared and combined with iterative metal artefact reduction (iMAR) to determine optimal imaging strategies for patients with metal prostheses. SECT and DECT scans were performed on a Siemens Somatom AS-64 Slice CT scanner. Images were acquired of a modified CIRS pelvis phantom with 6, 12, 20 mm diameter stainless steel rods and VME images reconstructed at 100, 120, 140 and 190 keV. These were post-reconstructed with and without the iMAR algorithm. Artefact reduction was measured using: (1) the change in Hounsfield Unit (HU) with and without metal artefact reduction (MAR) for 4 regions of interest; (2) the total number of artefact pixels, defined as pixels with a difference (between images with metal rod and without) exceeding a threshold; (3) the difference in the mean pixel intensity of the artefact pixels. DECT, SECT + iMAR and DECT + iMAR were compared. Both SECT + iMAR and DECT + iMAR offer successful MAR for phantom simulating unilateral hip prosthesis. DECT gives minimal artefact reduction over iMAR alone. Quantitative metrics are advantageous for MAR analysis but have limitations that leave room for metric development.

Randomized controlled study of the prediction of diminutive/small colorectal polyp histology using didactic versus computer-based self-learning module in gastroenterology trainees

BACKGROUND AND AIM

The aim of this randomized trial was to evaluate the performance of self-training versus didactic training in order to increase the diagnostic accuracy of diminutive/small colonic polyp histological prediction by trainees.

METHODS

Sixteen trainees reviewed 78 videos (48 iSCAN-OE and 30 NBI) of diminutive/small polyps in a pretraining assessment. Trainees were randomized to receive computer-based self-learning (n = 8) or didactic training (n = 8) using identical teaching materials and videos. The same 78 videos, in a different randomized order, were assessed. The NICE (NBI International Colorectal Endoscopic) and SIMPLE (Simplified Identification Method for Polyp Labeling during Endoscopy) classification systems were used to classify diminutive/small polyps.

RESULTS

A higher proportion of high-confidence predictions of polyps was made by the self-training group versus the didactic group using both the SIMPLE classification (77.1% [95% CI 73.4-80.3] vs 69.9% [95% CI 66.1-73.5%] [P = 0.005]) and the NICE classification (77% [95% CI 73.2-80.4%] vs 69.8% [95% CI 66-73.4%] [P = 0.006]). When using NICE, sensitivity of the self-training group compared with the didactic group was 72% versus 83% (P = 0.0005), and the accuracy was 66.1% versus 69.1%. The training improved the confidence of participants and SIMPLE was preferred over NICE.

CONCLUSION

Self-learning for the prediction of diminutive/small polyp histology is a method of training that can achieve results similar to didactic training. Availability of adequate self-learning teaching modules could enable widespread implementation of optical diagnosis in clinical practice.

The consensus recommendations of a group of international experts on the fundamental concepts related to the issues of testosterone deficiency and its treatment

Conference on the development of the international expert consensus to address frequently asked questions related to a medical condition of testosterone deficiency (TD, male hypogonadism) and testosterone therapy was held in Prague (Czech Republic) on October 1, 2015. The included experts were representatives from a variety of medical specialties, including urology, endocrinology, diabetology, internal medicine, as well as representatives of basic medical sciences. An international team of experts came to the following conclusions: TD - an important medical condition that affects the health and well-being of men; TD symptoms is a consequence of low testosterone levels, regardless of whether background etiology installed; TD consequences are global; care must be taken in an attempt to use any uniform threshold levels of testosterone for a decision on the appointment of testosterone therapy; a person does not have any reason to refrain from appointing testosterone therapy only on the basis of age; the existing evidence does not suggest increasing the prostate cancer or cardiovascular disease risk during testosterone therapy; there is evidence conserning the feasibility of a major research initiative to explore possible cardioprotective beneficial effects of testosterone therapy in men with metabolic disorders, including diabetes.