Management of acute perianal abscess: is surgeon specialization associated with improved outcomes?

BACKGROUND: Acute surgical units (ASU) are increasingly being adopted and in our system are staffed by colorectal and non-colorectal general surgeons. This study aims to evaluate whether surgeon specialization was associated with improved outcomes in perianal abscess. METHODS: Patients with perianal abscess admitted to the ASU between 2016 and 2020 were identified from a prospective database and their medical records reviewed. Patients with IBD, treatment for fistula-in-ano within the preceding year, or perianal sepsis of non-cryptoglandular origin were excluded. Patients admitted under an ASU colorectal (CR) consultant were compared with those under a non-CR general surgeon in a retrospective cohort study. Primary outcome was perianal abscess recurrence. For those without initial fistula, hazard of recurrent abscess or fistula was analysed. Multivariable Cox PH regression analysis was performed. RESULTS: Four-hundred and eight patients were included (150 CR, 258 non-CR). The CR group more frequently had a fistula identified at index operation (34.0% versus 10.9%, P < 0.0001). However, Cox multivariable analysis found no difference in hazard of recurrent abscess between groups (HR 1.12, 95% CI 0.65-1.95, P = 0.681)). Abscess recurred in 18.7% CR and 15.5% non-CR. Subsequent fistula developed in 14.7% in both groups. For patients without initial fistula, there was no difference between groups in hazard of recurrent abscess or fistula (HR 1.18, 95% CI 0.69-2.01, P = 0.539). CONCLUSION: Surgeon specialization was not associated with improved outcomes for ASU patients with perianal abscess, albeit with potential selection bias. CR surgeons were more proactive identifying fistulas; this raises the possibility that drainage alone may be adequate treatment.

Molecular and genomic characterisation of a panel of human anal cancer cell lines.

Anal cancer is a rare disease that has doubled in incidence over the last four decades. Current treatment and survival of patients with this disease has not changed substantially over this period of time, due, in part, to a paucity of preclinical models to assess new therapeutic options. To address this hiatus, we set-out to establish, validate and characterise a panel of human anal squamous cell carcinoma (ASCC) cell lines by employing an explant technique using fresh human ASCC tumour tissue. The panel of five human ASCC cell lines were validated to confirm their origin, squamous features and tumourigenicity, followed by molecular and genomic (whole-exome sequencing) characterisation. This panel recapitulates the genetic and molecular characteristics previously described in ASCC including phosphoinositide-3-kinase (PI3K) mutations in three of the human papillomavirus (HPV) positive lines and TP53 mutations in the HPV negative line. The cell lines demonstrate the ability to form tumouroids and retain their tumourigenic potential upon xenotransplantation, with varied inducible expression of major histocompatibility complex class I (MHC class I) and Programmed cell death ligand 1 (PD-L1). We observed differential responses to standard chemotherapy, radiotherapy and a PI3K specific molecular targeted agent in vitro, which correlated with the clinical response of the patient tumours from which they were derived. We anticipate this novel panel of human ASCC cell lines will form a valuable resource for future studies into the biology and therapeutics of this rare disease.

Delayed ileostomy closure increases the odds of Clostridium difficile infection.

AIM: A diverting ileostomy is typically performed to divert intestinal contents in high-risk colorectal anastomoses. Ileostomy closure is associated with high rates of postoperative Clostridium difficile infection (CDI). Risk factors for the development of CDI are unclear; however, a correlation has been observed with delayed closure. This study aimed to assess the odds of developing CDI in patients who had a delay to reversal of ileostomy, compared to those who had no delay. METHODS: A retrospective cohort study was conducted of patients undergoing reversal of ileostomy between 2010 and 2019 at a single tertiary centre. A delay to reversal of ileostomy was defined if the procedure was performed at >365 days following the index procedure. CDI was defined as the presence of Clostridium difficile toxin associated with diarrhoea. Univariable logistic regression analysis was performed to estimate odds of CDI for each covariable, comparing patients who had a delay to reversal of ileostomy with those who did not. Multivariable logistic regression analysis was used to adjust for the potential confounding effects of covariables. RESULTS: Of 195 patients, 11 (5.6%), developed postoperative CDI. Multivariable analysis showed that delay to reversal of ileostomy was associated with a nearly 7-fold increase in odds of CDI (OR = 6.95, CI: 1.06-81.6; p-value = 0.03). CONCLUSION: A delay to reversal of ileostomy of >365 days was associated with a higher incidence of CDI postoperatively. Careful consideration should be given to the timing of reversal and appropriate preoperative counselling of patients.

Increasing Incidence of Young-Onset Colorectal Carcinoma A 3-Country Population Analysis.

BACKGROUND: The overall incidence of colorectal carcinoma is declining in Western populations; however, single country series demonstrate an increase in young-onset (<50 years) colorectal carcinoma. OBJECTIVE: The purpose of this study was to determine whether the pattern of increasing incidence of young-onset colorectal carcinoma is consistent across 3 Western populations. DESIGN: This is a population incidence study. SETTINGS: National cancer registries of New Zealand, Sweden, and Scotland were used. PATIENTS: The incidence of colorectal carcinoma was calculated from population data for 3 countries over 2 to 4 decades. MAIN OUTCOME MEASURES: The incidence of colorectal carcinoma was measured. Incidence rate ratios were determined and data were stratified by subsite (colon versus rectum), sex, and age (<50, 50-79, and ≥80 y). RESULTS: Overall colorectal carcinoma rates declined in New Zealand, remained stable in Scotland, and increased in Sweden. In all 3 populations, there was an increasing incidence of rectal carcinoma in those aged <50 years. Young-onset rectal carcinoma increased in New Zealand (1995-2012: incidence rate ratio = 1.18 (men) and 1.13 (women)), with declining incidence in all other age groups. Colon carcinoma did not increase in the population aged <50 years, with the exception of distal colonic carcinoma in men. Overall, rectal carcinoma incidence increased (1970-2014) in Sweden; however, increases in those <50 years of age exceeded increases in other age groups (incidence rate ratio = 1.14 (males) and 1.12 (females)). Distal colon carcinoma increases were most marked in the population aged <50 years. In Scotland (1990-2014), young-onset rectal carcinoma incidence increased (incidence rate ratio = 1.23 (males) and 1.27 (females)), with a smaller increase in colon carcinoma. LIMITATIONS: Limitations include its registry-based, population incidence research. CONCLUSIONS: This study shows an increase in young-onset rectal carcinoma in 3 national populations; this observation may provide a focus for looking at the role of environmental influences on the etiology of this increase and therefore to explore strategies for prevention. See Video Abstract at http://links.lww.com/DCR/B194. AUMENTO DE LA INCIDENCIA DE CARCINOMA COLORRECTAL DE INICIO JOVEN: UN ANÁLISIS DE POBLACIÓN DE TRES PAÍSES: La incidencia global de carcinoma colorrectal está disminuyendo en las poblaciones occidentales. Sin embargo, las series de un solo país demuestran un aumento en el carcinoma colorrectal de inicio joven (pacientes menores de 50 años).Determinar si el patrón de incidencia en aumento de carcinoma colorrectal de inicio joven es consistente en tres poblaciones occidentales.Estudio de incidencias de población en tres países.Registros nacionales de cáncer de Nueva Zelanda, Suecia y Escocia.la incidencia de carcinoma colorrectal se calculó a partir de datos de población de tres países durante dos o a cuatro décadas.Incidencia de carcinoma colorrectal. Se determinaron las tasas de incidencia y los datos se estratificaron por subsitio (colon versus recto), además de sexo y edad (<50, 50-79 y ≥ 80).las tasas generales de carcinoma colorrectal disminuyeron en Nueva Zelanda, se mantuvieron estables en Escocia y aumentaron en Suecia. En las tres poblaciones, hubo una incidencia creciente de carcinoma rectal en pacientes menores de 50 años. El carcinoma rectal de inicio juvenil aumentó en Nueva Zelanda (1995-2012): tasa de incidencia de 1,18 [varones] y 1,13 [mujeres], con una disminución de la incidencia en todos los demás grupos de edad. El carcinoma de colon no aumentó en la población de < 50 años, con la excepción del carcinoma de colon distal en hombres. En general, la incidencia de carcinoma rectal aumentó (1970-2014) en Suecia; sin embargo, los aumentos en aquellos de <50 años excedieron los aumentos en otros grupos de edad: tasa de incidencia 1.14 [hombres] y 1.12 [mujeres]. Los aumentos del carcinoma de colon distal fueron más marcados en la población de < 50 años. En Escocia (1990-2014), la incidencia de carcinoma rectal de inicio juvenil aumentó: relación de tasa de incidencia 1.23 [hombres] y 1.27 [mujeres], con un aumento menor en el carcinoma de colon.Investigación de incidencia poblacional basada en registros nacionales.Este estudio muestra un aumento en el carcinoma rectal de inicio joven en tres poblaciones nacionales. Esta observación puede indicar un enfoque para la examinación de influencias ambientales en la etiología de este aumento y, por lo tanto, explorar estrategias para la prevención. Consulte Video Resumen en http://links.lww.com/DCR/B194. (Traducción-Dr Adrián Ortega).

Modes of carbon dioxide delivery during laparoscopy generate distinct differences in peritoneal damage and hypoxia in a porcine model.

BACKGROUND: Insufflation with CO2 can employ continuous flow, recirculated gas and/or additional warming and humidification. The ability to compare these modes of delivery depends upon the assays employed and opportunities to minimize subject variation. The use of pigs to train colorectal surgeons provided an opportunity to compare three modes of CO2 delivery under controlled circumstances. METHODS: Sixteen pigs were subjected to rectal resection, insufflated with dry-cold CO2 (DC-CO2) (n = 5), recirculated CO2 by an AirSeal device (n = 5) and humidification and warming (HW-CO2) by a HumiGard device (n = 6). Peritoneal biopsies were harvested from the same region of the peritoneum for fixation for immunohistochemistry for hypoxia-inducible factor 1 alpha (HIF-1α) and scanning electron microscopy (SEM) to evaluate hypoxia induction or tissue/cellular damage, respectively. RESULTS: DC-CO2 insufflation by both modes leads to significant damage to mesothelial cells as measured by cellular bulging and retraction as well as microvillus shortening compared with HW-CO2 at 1 to 1.5 h. DC-CO2 also leads to a rapid and significant induction of HIF-1α compared with HW-CO2. CONCLUSIONS: DC-CO2 insufflation induces substantive cellular damage and hypoxia responses within the first hour of application. The use of HW-CO2 insufflation ameliorates these processes for the first one to one and half hours in a large mammal used to replicate surgery in humans.

Risk Factors Associated With Circumferential Resection Margin Positivity in Rectal Cancer: A Binational Registry Study.

BACKGROUND: Rectal cancer outcomes have improved with the adoption of a multidisciplinary model of care. However, there is a spectrum of quality when viewed from a national perspective, as highlighted by the Consortium for Optimizing the Treatment of Rectal Cancer data on rectal cancer care in the United States. OBJECTIVE: The aim of this study was to assess and identify predictors of circumferential resection margin involvement for rectal cancer across Australasia. DESIGN: A retrospective study from a prospectively maintained binational colorectal cancer database was interrogated. SETTINGS: This study is based on a binational colorectal cancer audit database. PATIENTS: Clinical information on all consecutive resected rectal cancer cases recorded in the registry from 2007 to 2016 was retrieved, collated, and analyzed. MAIN OUTCOME MEASURES: The primary outcome measure was positive circumferential resection margin, measured as a resection margin ≤1 mm. RESULTS: A total of 3367 patients were included, with 261 (7.5%) having a positive circumferential resection margin. After adjusting for hospital and surgeon volume, hierarchical logistic regression analysis identified a 6-variable model encompassing the independent predictors, including urgent operation, abdominoperineal resection, open technique, low rectal cancer, T3 to T4, and N1 to N2. The accuracy of the model was 92.3%, with an receiver operating characteristic of 0.783 (p < 0.0001). The quantitative risk associated with circumferential resection margin positivity ranged from <1% (no risk factors) to 43% (6 risk factors). LIMITATIONS: This study was limited by the lack of recorded long-term outcomes associated with circumferential resection margin positivity. CONCLUSIONS: The rate of circumferential resection margin involvement in patients undergoing rectal cancer resection in Australasia is low and is influenced by a number of factors. Risk stratification of outcome is important with the increasing demand for publicly accessible quality data. See Video Abstract at http://links.lww.com/DCR/A512.

Colonoscopic surveillance: quality, guidelines and effectiveness.

Colonoscopic surveillance in patients with a personal or family history of colorectal carcinoma or colonic polyps represents a significant workload for endoscopy services. Effective colonoscopic surveillance relies on quality endoscopic examination and appropriate surveillance interval. This review will discuss quality in colonoscopy and review guidelines for surveillance.

Dispelling misconceptions in the management of familial adenomatous polyposis.

Patients with familial adenomatous polyposis require surgical intervention at some point in their lives. The diagnosis is often apparent from their phenotype and family history, however, this is not always the case. Many factors can influence the surgical strategy although the polyposis burden and distribution remain the main consideration. While prophylactic removal of the rectum and colon is often required, sparing the rectum at the index surgery is safe in select patients. This article aims to dispel misconceptions in the diagnosis and treatment of patients with familial adenomatous polyposis.