A97 LARGE NON-PEDUNCULATED COLONIC POLYP (LNPCP) OUTCOMES REFERRED FOR ENDOSCOPIC RESECTION IN BRITISH COLUMBIA: A QUALITY ASSURANCE INITIATIVE

Background

Endoscopic resection techniques have become the primary treatment strategy for the vast majority of large (≥ 20mm) non-pedunculated colonic polyps (LNPCPs). Despite this, surgery is still commonly performed with evidence suggesting an increasing trend over time. There is limited Canadian data confirming the effectiveness and safety of an endoscopic management strategy for LNPCPs.

Purpose

To investigate clinical outcomes of patients referred for endoscopic management of a LNPCP.

Method

Retrospective single-centre analysis of patients referred to a single endoscopist for the management of LNPCPs within a tertiary referral practice. LNPCPs were further subdivided into non-complicated (NC-LNPCP) or complicated (C-LNPCP) defined as those involving the ileocecal valve, appendiceal orifice, circumferential or previously attempted. Performance outcomes were evaluated by the frequencies of technical success (removal of all polypoid tissue during index procedure) and need for colorectal surgery. Safety was evaluated by the frequencies of clinically significant intraprocedural bleeding (CSIPB), clinically significant post-endoscopic resection bleeding (CSPEB), intra-procedural perforation and delayed perforation. Recurrence (either endoscopic or histologic) was evaluated at first surveillance colonoscopy (SC1). Continuous variables were summarized using median (IQR). Categorical variables were summarized as frequencies (%). To test for association between categorical variables, the Pearson χ2 or the Fisher exact test were used, where appropriate. For continuous variables, the Mann-Whitney U test was used. A probability (p) value of <0.05 was considered statistically significant.

Result(s)

Between January 2021 to March 2022, 263 LNPCP were referred for endoscopic resection and 41 LNPCP were excluded (23 pedunculated, 14 optical evaluation suggestive of deeply invasive cancer, 4 other). 222 LNPCP (188 NC-LNPCP, 34 C-LNPCP) underwent endoscopic resection. Median size was 25mm (IQR 20-30mm) with the majority undergoing cold snare resection (115, 51.8%). Polyposis (Adenomatous or serrated) was present in 23 (12.6%) cases respectively. Technical success was 97.3%. Cancer was present in 5 (2%). Clinically significant bleeding (CSPEB) occurred in 2.7%, DMI IV in 1.8% and there were no delayed perforations. Recurrence occurred in 4 (3.5%) at SC1 and 11 (5%) required surgery due to technical failure, submucosal invasion on pathology and clinically significant bleeding.

Image

Conclusion(s)

Endoscopic resection as the primary treatment strategy for LNPCPs offers a safe and effective alternative to surgery in British Columbia.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

A122 MINIMALLY INVASIVE ENDOSCOPIC RESECTION TECHNIQUES FOR ANORECTAL JUNCTION NEOPLASIA: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

The management of neoplastic lesions at the anorectal junction remains debated. Endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) have emerged as the primary endoscopic modalities of choice.

Purpose

We sought to compare the performance of ESD and EMR in resection of anorectal neoplasia.

Method

Two authors independently searched MEDLINE, EMBASE and Cochrane Libraries (Jan 2000 – Aug 2021) for citations evaluating the performance of endoscopic resection techniques (ESD, EMR) for lesions involving the anorectal junction (defined as within 20mm of the dentate line). The frequencies and 95% confidence intervals (95% CI) of technical success (complete removal of all neoplastic tissue at index procedure), clinically significant post-endoscopic resection bleeding (CSPEB), delayed perforation, recurrence and referral to surgery were assessed using random-effects modelling.

Result(s)

We included 11 studies (total 563 patients: 414 ESD, 149 EMR) of which nine were ESD and two were EMR studies. Technical success was achieved in 97.2% overall (95% CI 94.8%-98.5%, ESD 97.5% and EMR range 93.9%-98.0%). Clinically significant post-endoscopic resection bleeding occurred in 4.3% (95% CI 1.6%-11.1%, ESD 3.0% and EMR range 8.2%-11.0%). Delayed perforation was not identified. Recurrence at first screening colonoscopy occurred in 4.8% (95% CI 1.9%-11.7%, ESD 3.0% and EMR range 15.4%-18.4%). Referral to surgery for any reason occurred in 5.9% (95% CI 4.3%-8.0%, ESD 6.9%, EMR range 2.0%-3.0%).

Conclusion(s)

ESD and EMR demonstrate high frequencies of technical success but may have different rates of adverse events and recurrence. More studies investigating lesions at the anorectal junction should be conducted including head-to-head analyses between ESD and EMR for low-risk anorectal junction neoplasia.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

A132 A CASE OF COLONIC MALAKOPLAKIA PRESENTING AS A LARGE CECAL MASS : NOT EVERY POLYP HAS TO LOOK LIKE A NAIL

Background

Malakoplakia is a rare inflammatory condition, commonly affecting the genitourinary system of immunocompromised patients. Gastrointestinal malakoplakia has been reported in the literature, with previous endoscopic findings mimicking mass lesions.

Purpose

To describe a case of colonic malakoplakia after referral for endoscopic management of a large non-pedunculated colorectal polyp.

Method

Case report and review of the literature.

Result(s)

Case Report

An 80-year-old male with chronic kidney disease and remote renal transplant on immunosuppressive therapy (mycophenolate mofetil, tacrolimus, prednisone) was referred for endoscopic resection for a large non-pedunculated colorectal polyp in the cecum. Original presenting symptoms included chronic diarrhea, iron deficiency anemia, and fecal immunochemical test (FIT) positivity. A repeat colonoscopy demonstrated a 40mm Paris 0-IIA plaque-like lesion in the cecum with optical features not in keeping with adenomatous or serrated histopathology. Biopsies were performed with histopathology demonstrating normal colonic mucosa with confluent sheets of histiocytes with concentrically layered cytoplasmic inclusions, in keeping with malakoplakia.

Literature review

Malakoplakia, Greek for “soft plaque”, is a rare inflammatory condition characterized by impaired dysfunction in macrophages leading to the accumulation of incompletely degraded bacteria in phagolysosomes. Histologically, this appears as concentrically layered cytoplasmic inclusions, comprising the pathognomonic Michaelis-Gutmann bodies. Many bacterial organisms have been implicated in the development of malakoplakia, with E. coli being the most common; specifically in immunocompromised patients, whether from immunosuppressive medications, immunodeficiency syndromes, or clinical conditions precluding effective immune function. Malakoplakia commonly presents as a mass-like lesion and has been found in all organs, most commonly in the genitourinary system. Diagnosis is made by biopsy and allows for appropriate treatment, which is most commonly a reduction in immunosuppressive therapy and antibiotic therapy.

Image

Conclusion(s)

Malakoplakia is rare but should be considered when a lesion with atypical optical evaluation features is found in immunocompromised individuals or those with recurrent infections.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

A138 SERRATED POLYPOSIS SYNDROME IN INFLAMMATORY BOWEL DISEASE: A SEQUELAE OF CHRONIC DISEASE ACTIVITY OR NEW WHO PHENOTYPE?

Background

Serrated polyposis syndrome (SPS) is a growing health concern with up to 1 in 125 universal screening program participants meeting diagnostic criteria. Conversely, SPS in inflammatory bowel disease (IBD) is rarely described in the literature, despite the predisposition for serrated epithelial change and serrated polyps in this population.

Purpose

To describe a case of World Health Organization (WHO) criterion I SPS in a patient with IBD, and discuss the existing literature on this rare occurrence.

Method

Case report and review of the literature.

Result(s)

Case Report

A 53-year-old female with ulcerative colitis (UC; Phenotype: Left-sided; Duration of disease: 40 years; Medical therapy: sulfasalazine) undergoing regular endoscopic surveillance was recently found to have multiple serrated-class lesions including 6 in the sigmoid colon ranging between 8-30mm in size; this included 3 sessile serrated lesions (SSLs) between 20-30mm removed by piecemeal cold snare resection without complication and 2 residual large SSLs for staged endoscopic resection. No endoscopic disease activity was appreciated (Mayo 0), with histopathology of the sigmoid colon and rectum demonstrating chronic inactive colitis.

Literature Review

From 2008 to 2021, there are eleven reported cases of SPS in IBD. Six patients had UC and most were in remission for several decades at the time of SPS diagnosis. Most SPS cases met WHO criteria and fit within described phenotypes. While the case above meets WHO criterion I for SPS, the presence of large distal lesions is atypical, raising the question of whether chronic disease activity contributed to the development of these serrated lesions, given the known predisposition for serrated epithelial change and serrated lesions in patients with colonic IBD.

Image

Conclusion(s)

SPS in patients with IBD is rare. Questions remain about the role of chronic disease activity contributing to the formation of serrated lesions, its clinical relevance, and optimal management strategy.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

A120 ENDOSCOPIC CLOSURE TECHNIQUES FOLLOWING ACUTE IATROGENIC PERFORATION -- AN UPDATED SYSTEMATIC REVIEW

Background

Iatrogenic perforation is arguably the most feared adverse event associated with endoscopy. Current American Society for Gastrointestinal Endoscopy (ASGE) and European Society of Gastroenterology Endoscopy (ESGE) guidelines recommend endoscopic closure as the first-line treatment strategy. Historically, this has been achieved using through-the-scope clips (TTSC). Given the emergence of alternative endoscopic closure techniques including over-the-scope clips (OTSC) and endoscopic suturing, we sought to provide an updated review of the literature.

Purpose

To review endoscopic closure techniques following iatrogenic perforation during screening or therapeutic endoscopy.

Method

Based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines, an electronic search of MEDLINE and EMBASE from June 1^st, 1946 – Oct 10^th, 2022 was performed. Inclusion criteria was limited to English full-text original citations, with case reports, and cohorts with < 3 patients excluded. Our primary objective was to assess complete defect closure after attempted endoscopic treatment. Outcomes were stratified by modality (TTSC, OTSC, endoscopic suturing) and chronologically based on a previous well received systematic review.

Result(s)

A total of 2549 citations were identified in our electronic search, of which 34 were included representing 830 perforations. Overall, successful endoscopic closure was achieved in 763 cases (91.9%). When stratified by endoscopic closure techniques, range estimates for successful endoscopic closure was 71% – 100%, 57% - 100%, and 100% for TTSC, OTSC and endoscopic suturing respectively. When stratifying chronologically, an improvement in TTSC closure was identified.

Conclusion(s)

Endoscopic defect closure, including TTSC, OTSC and endoscopic suturing, are effective in the management of iatrogenic perforations with increasing TTSC performance over time. It remains the primary treatment strategy for iatrogenic perforation.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

SBML to bond graphs: From conversion to composition

The Systems Biology Markup Language (SBML) is a popular software-independent XML-based format for describing models of biological phenomena. The BioModels Database is the largest online repository of SBML models. Several tools and platforms are available to support the reuse and composition of SBML models. However, these tools do not explicitly assess whether models are physically plausible or thermodynamically consistent. This often leads to ill-posed models that are physically impossible, impeding the development of realistic complex models in biology. Here, we present a framework that can automatically convert SBML models into bond graphs, which imposes energy conservation laws on these models. The new bond graph models are easily mergeable, resulting in physically plausible coupled models. We illustrate this by automatically converting and coupling a model of pyruvate distribution to a model of the pentose phosphate pathway.

A semantics, energy-based approach to automate biomodel composition

Hierarchical modelling is essential to achieving complex, large-scale models. However, not all modelling schemes support hierarchical composition, and correctly mapping points of connection between models requires comprehensive knowledge of each model's components and assumptions. To address these challenges in integrating biosimulation models, we propose an approach to automatically and confidently compose biosimulation models. The approach uses bond graphs to combine aspects of physical and thermodynamics-based modelling with biological semantics. We improved on existing approaches by using semantic annotations to automate the recognition of common components. The approach is illustrated by coupling a model of the Ras-MAPK cascade to a model of the upstream activation of EGFR. Through this methodology, we aim to assist researchers and modellers in readily having access to more comprehensive biological systems models.

Hierarchical semantic composition of biosimulation models using bond graphs

Simulating complex biological and physiological systems and predicting their behaviours under different conditions remains challenging. Breaking systems into smaller and more manageable modules can address this challenge, assisting both model development and simulation. Nevertheless, existing computational models in biology and physiology are often not modular and therefore difficult to assemble into larger models. Even when this is possible, the resulting model may not be useful due to inconsistencies either with the laws of physics or the physiological behaviour of the system. Here, we propose a general methodology for composing models, combining the energy-based bond graph approach with semantics-based annotations. This approach improves model composition and ensures that a composite model is physically plausible. As an example, we demonstrate this approach to automated model composition using a model of human arterial circulation. The major benefit is that modellers can spend more time on understanding the behaviour of complex biological and physiological systems and less time wrangling with model composition.

Diagnostic accuracy of echocardiography for pulmonary hypertension: a systematic review and meta-analysis

CONTEXT

Right heart catheterisation is the gold standard for the diagnosis of pulmonary hypertension. However, echocardiography is frequently used to screen for this disease and monitor progression over time because it is non-invasive, widely available and relatively inexpensive.

OBJECTIVE

To perform a systematic review and quantitative meta-analysis to determine the correlation of pulmonary pressures obtained by echocardiography versus right heart catheterisation and to determine the diagnostic accuracy of echocardiography for pulmonary hypertension.

DATA SOURCES

MEDLINE, EMBASE, Papers First, the Cochrane collaboration and the Cochrane Register of controlled trials were searched and were inclusive as of February 2010.

STUDY SELECTION

Studies were only included if a correlation coefficient or the absolute number of true-positive, false-negative, true-negative and false-positive observations was available, and the 'reference standards' were described clearly.

DATA EXTRACTION

Two reviewers independently extracted the data from each study. Quality was assessed with the quality assessment for diagnostic accuracy studies. A random effects model was used to obtain a summary correlation coefficient and the bivariate model for diagnostic meta-analysis was used to obtain summary sensitivity and specificity values. Results 29 studies were included in the meta-analysis.The summary correlation coefficient between systolic pulmonary arterial pressure estimated from echocardiography versus measured by right heart catheterisation was 0.70 (95% CI 0.67 to 0.73; n=27).The summary sensitivity and specificity for echocardiography for diagnosing pulmonary hypertension was 83% (95% CI 73 to 90) and 72% (95% CI 53 to 85;n=12), respectively. The summary diagnostic OR was 13(95% CI 5 to 31).Conclusions Echocardiography is a useful and noninvasive modality for initial measurement of pulmonary pressures but due to limitations, right heart catheterisation should be used for diagnosing and monitoring pulmonary hypertension.

A comparison of ketorolac tromethamine and acetaminophen codeine in the management of acute apical periodontitis

Effective management of severe endodontic pain is often a major problem. The analgesic effect of ketorolac tromethamine (Toradol, 10 mg p.o.) was compared with acetaminophen codeine (325 mg/15 mg p.o.) in patients with severe pain due to acute apical periodontitis in a double-blind clinical study. A total of 66 patients presenting with severe pain (defined as 7 cm and more using a visual analog scale) were randomly assigned to receive either ketorolac tromethamine or acetaminophen codeine (33 patients in each group), and recorded their pain score once every 10 min for 90 min after administration. Results indicate that patients in the ketorolac group had significantly less pain than those who received acetaminophen codeine (p = 0.005).

Central role of tumour necrosis factor, GM-CSF, and interleukin 1 in the pathogenesis of juvenile chronic myelogenous leukaemia

In previous studies on patients with juvenile chronic myelogenous leukaemia (JCML), we found excessive proliferation of malignant monocyte-macrophage elements in the absence of exogenous growth factor, and impaired growth of normal haematopoietic progenitors. In the current study, six newly-diagnosed JCML patients were investigated to characterize the disease further. In co-cultures, JCML cell culture supernatant as well as patient plasma obtained at diagnosis produced a striking reduction in numbers of control marrow BFU-E, CFU-GM, CFU-Meg and CFU-GEMM colonies. Monoclonal anti-tumour necrosis factor alpha neutralizing antibodies (anti-TNF-alpha Ab) abolished these inhibitory properties. In sharp contrast, JCML supernatants exerted a marked growth-promoting effect on autologous JCML cells cultured in clonogenic assays. Anti-TNF-alpha Ab and anti-granulocyte-macrophage colony-stimulating factor neutralizing antibodies (anti-GM-CSF Ab) both reversed the stimulating effect. Recombinant GM-CSF and recombinant TNF alpha produced a profound increase in JCML colonies when tested individually and anti-GM-CSF Ab reversed the TNF-alpha effect. Expression studies of TNF-alpha and TNF-alpha receptor genes of cultured JCML cells demonstrated mRNAs for both. Further, TNF-alpha activity was assayed in a wide variety of cell culture supernatants and in normal and patients' plasma, and only the JCML specimens showed increased TNF-alpha values. Recombinant interleukin-1 alpha (IL-1 alpha) also stimulated JCML colony growth, but polyclonal anti-IL-1 neutralizing antibodies did not suppress JCML colony numbers nor did it reverse the effects of TNF-alpha or GM-CSF. The evidence indicated that the JCML monokine which inhibits normal haematopoiesis is TNF-alpha and that the endogenously-produced TNF-alpha and GM-CSF from JCML cells play an important role in the pathogenesis of the disease by acting as autocrine growth factors. IL-1 alpha also stimulates JCML cell proliferation as an accessory factor and augments the effect of GM-CSF, TNF-alpha or both.

T-lymphoblasts with erythropoietic helper function in acute T-cell leukemia

A patient with acute T-lymphoblastic leukemia was found to maintain a normal hemoglobin concentration both at presentation and preterminally several months later, despite a replaced bone marrow and over 80% circulating lymphoblasts on both occasions. Cell surface marker analysis demonstrated the T-lymphoblasts both at presentation and preterminally to belong to the T-helper subpopulation. In vitro culture studies demonstrated that the patient's T-lymphoblasts, as well as conditioned medium derived from these lymphoblasts, significantly stimulated normal bone marrow erythroid colony growth (CFU-E). These findings suggest that in this patient the preservation of erythropoiesis resulted from a helper effect exerted by his T-lymphoblasts.

Down syndrome and acute leukemia in children: a 10-year retrospective survey from Childrens Cancer Study Group

Review of 5406 children with acute lymphoblastic (ALL) or nonlymphoblastic leukemia (ANLL) registered with Childrens Cancer Study Group (CCSG) since 1972 identified 115 patients (2.1%) with Down syndrome. The proportion of patients with Down syndrome was the same for ALL (2.1%) and ANLL (2.1%). Patients with ALL with and without Down syndrome did not differ significantly with respect to age at diagnosis, sex, race, morphology (FAB classification), cell surface markers, initial white blood cell count, pretreatment hemoglobin value, hepatomegaly, lymphadenopathy, presence of mediastinal mass, CNS disease at diagnosis, or prognostic group as defined by age and initial white blood cell count. Patients with ALL-Down syndrome less frequently had splenomegaly, had lower pretreatment platelet counts, and more often had normal or elevated IgG or IgA levels. In addition, they had a significantly lower rate of remission (81% versus 94%), a higher mortality during induction therapy (14% versus 3%), and a poorer overall survival with 5-year life table rates of 50% versus 65% (P less than 0.001). If an initial remission was achieved, there were no significant differences with respect to remission duration, survival, or disease-free survival. Patients with ANLL-Down syndrome were younger at diagnosis than those without Down syndrome. There was no significant difference in the remission rates between these patients. Analysis of findings in patients with ANLL provided results similar to those obtained for patients with ALL with regard to clinical outcome after achievement of an initial remission.